fMRI/MEG出版物

@article{Wang2016e,

title = {Rhythm makes the world go round: An MEG-TMS study on the role of right TPJ theta oscillations in embodied perspective taking},

author = {Hongfang Wang and Eleanor Callaghan and Gerard Gooding-Williams and Craig McAllister and Klaus Kessler},

doi = {10.1016/j.cortex.2015.11.011},

year  = {2016},

date = {2016-01-01},

journal = {Cortex},

volume = {75},

pages = {68–81},

publisher = {Elsevier Ltd},

abstract = {While some aspects of social processing are shared between humans and other species, some aspects are not. The former seems to apply to merely tracking another's visual perspective in the world (i.e., what a conspecific can or cannot perceive), while the latter applies to perspective taking in form of mentally "embodying" another's viewpoint. Our previous behavioural research had indicated that only perspective taking, but not tracking, relies on simulating a body schema rotation into another's viewpoint. In the current study we employed Magnetoencephalography (MEG) and revealed that this mechanism of mental body schema rotation is primarily linked to theta oscillations in a wider brain network of body-schema, somatosensory and motor-related areas, with the right posterior temporo-parietal junction (pTPJ) at its core. The latter was reflected by a convergence of theta oscillatory power in right pTPJ obtained by overlapping the separately localised effects of rotation demands (angular disparity effect), cognitive embodiment (posture congruence effect), and basic body schema involvement (posture relevance effect) during perspective taking in contrast to perspective tracking. In a subsequent experiment we interfered with right pTPJ processing using dual pulse Transcranial Magnetic Stimulation (dpTMS) and observed a significant reduction of embodied processing. We conclude that right TPJ is the crucial network hub for transforming the embodied self into another's viewpoint, body and/or mind, thus, substantiating how conflicting representations between self and other may be resolved and potentially highlighting the embodied origins of high-level social cognition in general.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Park2016,

title = {Lip movements entrain the observers' low-frequency brain oscillations to facilitate speech intelligibility},

author = {Hyojin Park and Christoph Kayser and Gregor Thut and Joachim Gross},

doi = {10.7554/eLife.14521},

year  = {2016},

date = {2016-01-01},

journal = {eLife},

volume = {5},

pages = {1–17},

abstract = {During continuous speech, lip movements provide visual temporal signals that facilitate speech processing. Here, using MEG we directly investigated how these visual signals interact with rhythmic brain activity in participants listening to and seeing the speaker. First, we investigated coherence between oscillatory brain activity and speaker's lip movements and demonstrated significant entrainment in visual cortex. We then used partial coherence to remove contributions of the coherent auditory speech signal from the lip-brain coherence. Comparing this synchronization between different attention conditions revealed that attending visual speech enhances the coherence between activity in visual cortex and the speaker's lips. Further, we identified a significant partial coherence between left motor cortex and lip movements and this partial coherence directly predicted comprehension accuracy. Our results emphasize the importance of visually entrained and attention-modulated rhythmic brain activity for the enhancement of audiovisual speech processing.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tan2016,

title = {MEG sensor and source measures of visually induced gamma-band oscillations are highly reliable},

author = {Heng Ru May Tan and Joachim Gross and P. J. Uhlhaas},

doi = {10.1016/j.neuroimage.2016.05.006},

year  = {2016},

date = {2016-01-01},

journal = {NeuroImage},

volume = {137},

pages = {34–44},

publisher = {The Authors},

abstract = {High frequency brain oscillations are associated with numerous cognitive and behavioral processes. Non-invasive measurements using electro-/magnetoencephalography (EEG/MEG) have revealed that high frequency neural signals are heritable and manifest changes with age as well as in neuropsychiatric illnesses. Despite the extensive use of EEG/MEG-measured neural oscillations in basic and clinical research, studies demonstrating test-retest reliability of power and frequency measures of neural signals remain scarce. Here, we evaluated the test-retest reliability of visually induced gamma (30-100 Hz) oscillations derived from sensor and source signals acquired over two MEG sessions. The study required participants (N = 13) to detect the randomly occurring stimulus acceleration while viewing a moving concentric grating. Sensor and source MEG measures of gamma-band activity yielded comparably strong reliability (average intraclass correlation},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pape2016,

title = {Motor cortex activity predicts response alternation during sensorimotor decisions},

author = {Anna Antonia Pape and Markus Siegel},

doi = {10.1038/ncomms13098},

year  = {2016},

date = {2016-01-01},

journal = {Nature Communications},

volume = {7},

pages = {13098},

publisher = {Nature Publishing Group},

abstract = {Our actions are constantly guided by decisions based on sensory information. The motor cortex is traditionally viewed as the final output stage in this process, merely executing motor responses based on these decisions. However, it is not clear if, beyond this role, the motor cortex itself impacts response selection. Here, we report activity fluctuations over motor cortex measured using MEG, which are unrelated to choice content and predict responses to a visuomotor task seconds before decisions are made. These fluctuations are strongly influenced by the previous trial's response and predict a tendency to switch between response alternatives for consecutive decisions. This alternation behaviour depends on the size of neural signals still present from the previous response. Our results uncover a response-alternation bias in sensorimotor decision making. Furthermore, they suggest that motor cortex is more than an output stage and instead shapes response selection during sensorimotor decision making.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Spaak2016,

title = {The neural mechanisms of prediction in visual search},

author = {Eelke Spaak and Yvonne Fonken and Ole Jensen and Floris P. Lange},

doi = {10.1093/cercor/bhv210},

year  = {2016},

date = {2016-01-01},

journal = {Cerebral Cortex},

volume = {26},

number = {11},

pages = {4327–4336},

abstract = {The speed of visual search depends on bottom-up stimulus features (e.g., we quickly locate a red item among blue distractors), but it is also facilitated by the presence of top-down perceptual predictions about the item. Here, we identify the nature, source, and neuronal substrate of the predictions that speed up resumed visual search. Human subjects were presented with a visual search array that was repeated up to 4 times, while brain activity was recorded using magnetoencephalography (MEG). Behaviorally, we observed a bimodal reaction time distribution for resumed visual search, indicating that subjects were extraordinarily rapid on a proportion of trials. MEG data demonstrated that these rapid-response trials were associated with a prediction of (1) target location, as reflected by alpha-band (8-12 Hz) lateralization; and (2) target identity, as reflected by beta-band (15-30 Hz) lateralization. Moreover, we show that these predictions are likely generated in a network consisting of medial superior frontal cortex and right temporo-parietal junction. These findings underscore the importance and nature of perceptual hypotheses for efficient visual search.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Shigihara2016,

title = {Early visual cortical responses produced by checkerboard pattern stimulation},

author = {Yoshihito Shigihara and Hideyuki Hoshi and Semir Zeki},

doi = {10.1016/j.neuroimage.2016.03.078},

year  = {2016},

date = {2016-01-01},

journal = {NeuroImage},

volume = {134},

pages = {532–539},

publisher = {Elsevier B.V.},

abstract = {Visual evoked potentials have been traditionally triggered with flash or reversing checkerboard stimuli and recorded with electroencephalographic techniques, largely but not exclusively in clinical or clinically related settings. They have been crucial in determining the healthy functioning or otherwise of the visual pathways up to and including the cerebral cortex. They have typically given early response latencies of 100 ms, the source of which has been attributed to V1, with the prestriate cortex being secondarily activated somewhat later. On the other hand, magnetoencephalographic studies using stimuli better tailored to the physiology of individual, specialized, visual areas have given early latencies of <. 50 ms with the sources localized in both striate (V1) and prestriate cortex. In this study, we used the reversing checkerboard pattern as a stimulus and recorded cortical visual evoked magnetic fields with magnetoencephalography, to establish whether very early responses can be traced to (estimated) in both striate and prestriate cortex, since such a demonstration would enhance considerably the power of this classical approach in clinical investigations. Our results show that cortical responses evoked by checkerboard patterns can be detected before 50 ms post-stimulus onset and that their sources can be estimated in both striate and prestriate cortex, suggesting a strong parallel input from the sub-cortex to both striate and prestriate divisions of the visual cortex.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Roth2016,

title = {Functional MRI representational similarity analysis reveals a dissociation between discriminative and relative location information in the human visual system},

author = {Zvi N. Roth},

doi = {10.3389/fnint.2016.00016},

year  = {2016},

date = {2016-01-01},

journal = {Frontiers in Integrative Neuroscience},

volume = {10},

pages = {16},

abstract = {Neural responses in visual cortex are governed by a topographic mapping from retinal locations to cortical responses. Moreover, at the voxel population level early visual cortex (EVC) activity enables accurate decoding of stimuli locations. However, in many cases information enabling one to discriminate between locations (i.e. discriminative information) may be less relevant than information regarding the relative location of two objects (i.e. relative information). For example, when planning to grab a cup, determining whether the cup is located at the same retinal location as the hand is hardly relevant, whereas the location of the cup relative to the hand is crucial for performing the action. We have previously used multivariate pattern analysis techniques to measure discriminative location information, and found the highest levels in early visual cortex, in line with other studies. Here we show, using representational similarity analysis, that availability of discriminative information in fMRI activation patterns does not entail availability of relative information. Specifically, we find that relative location information can be reliably extracted from activity patterns in posterior intraparietal sulcus (pIPS), but not from EVC, where we find the spatial representation to be warped. We further show that this variability in relative information levels between regions can be explained by a computational model based on an array of receptive fields. Moreover, when the model's receptive fields are extended to include inhibitory surround regions, the model can account for the spatial warping in EVC. These results demonstrate how size and shape properties of receptive fields in human visual cortex contribute to the transformation of discriminative spatial representation into relative spatial representation along the visual stream.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Schuster2016,

title = {Words in context: The effects of length, frequency, and predictability on brain responses during natural reading},

author = {Sarah Schuster and Stefan Hawelka and Florian Hutzler and Martin Kronbichler and Fabio Richlan},

doi = {10.1093/cercor/bhw184},

year  = {2016},

date = {2016-01-01},

journal = {Cerebral Cortex},

volume = {26},

number = {10},

pages = {3889–3904},

abstract = {Word length, frequency, and predictability count among the most influential variables during reading. Their effects are well-documented in eye movement studies, but pertinent evidence from neuroimaging primarily stem from single-word presentations. We investigated the effects of these variables during reading of whole sentences with simultaneous eye-tracking and functional magnetic resonance imaging (fixation-related fMRI). Increasing word length was associated with increasing activation in occipital areas linked to visual analysis. Additionally, length elicited a U-shaped modulation (i.e., least activation for medium-length words) within a brain stem region presumably linked to eye movement control. These effects, however, were diminished when accounting for multiple fixation cases. Increasing frequency was associated with decreasing activation within left inferior frontal, superior parietal, and occipito-temporal regions. The function of the latter region-hosting the putative visual word form area-was originally considered as limited to sublexical processing. An exploratory analysis revealed that increasing predictability was associated with decreasing activation within middle temporal and inferior frontal regions previously implicated in memory access and unification. The findings are discussed with regard to their correspondence with findings from single-word presentations and with regard to neurocognitive models of visual word recognition, semantic processing, and eye movement control during reading.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Steffens2016,

title = {Effects of ketamine on brain function during smooth pursuit eye movements},

author = {Maria Steffens and B. Becker and C. Neumann and Anna-Maria Kasparbauer and Inga Meyhöfer and Bernd Weber and Mitul A. Mehta and R. Hurlemann and Ulrich Ettinger},

doi = {10.1002/hbm.23294},

year  = {2016},

date = {2016-01-01},

journal = {Human Brain Mapping},

volume = {37},

number = {11},

pages = {4047–4060},

abstract = {The uncompetitive NMDA receptor antagonist ketamine has been proposed to model symptoms of psychosis. Smooth pursuit eye movements (SPEM) are an established biomarker of schizophrenia. SPEM performance has been shown to be impaired in the schizophrenia spectrum and during ketamine administration in healthy volunteers. However, the neural mechanisms mediating SPEM impairments during ketamine administration are unknown. In a counter-balanced, placebo-controlled, double-blind, within-subjects design, 27 healthy participants received intravenous racemic ketamine (100 ng/mL target plasma concentration) on one of two assessment days and placebo (intravenous saline) on the other. Participants performed a block-design SPEM task during functional magnetic resonance imaging (fMRI) at 3 Tesla field strength. Self-ratings of psychosis-like experiences were obtained using the Psychotomimetic States Inventory (PSI). Ketamine administration induced psychosis-like symptoms, during ketamine infusion, participants showed increased ratings on the PSI dimensions cognitive disorganization, delusional thinking, perceptual distortion and mania. Ketamine led to robust deficits in SPEM performance, which were accompanied by reduced blood oxygen level dependent (BOLD) signal in the SPEM network including primary visual cortex, area V5 and the right frontal eye field (FEF), compared to placebo. A measure of connectivity with V5 and FEF as seed regions, however, was not significantly affected by ketamine. These results are similar to the deviations found in schizophrenia patients. Our findings support the role of glutamate dysfunction in impaired smooth pursuit performance and the use of ketamine as a pharmacological model of psychosis, especially when combined with oculomotor biomarkers.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Talanow2016,

title = {Facing competition: Neural mechanisms underlying parallel programming of antisaccades and prosaccades},

author = {Tobias Talanow and Anna-Maria Kasparbauer and Maria Steffens and Inga Meyhöfer and Bernd Weber and Nikolaos Smyrnis and Ulrich Ettinger},

doi = {10.1016/j.bandc.2016.05.006},

year  = {2016},

date = {2016-01-01},

journal = {Brain and Cognition},

volume = {107},

pages = {37–47},

publisher = {Elsevier Inc.},

abstract = {The antisaccade task is a prominent tool to investigate the response inhibition component of cognitive control. Recent theoretical accounts explain performance in terms of parallel programming of exogenous and endogenous saccades, linked to the horse race metaphor. Previous studies have tested the hypothesis of competing saccade signals at the behavioral level by selectively slowing the programming of endogenous or exogenous processes e.g. by manipulating the probability of antisaccades in an experimental block. To gain a better understanding of inhibitory control processes in parallel saccade programming, we analyzed task-related eye movements and blood oxygenation level dependent (BOLD) responses obtained using functional magnetic resonance imaging (fMRI) at 3T from 16 healthy participants in a mixed antisaccade and prosaccade task. The frequency of antisaccade trials was manipulated across blocks of high (75%) and low (25%) antisaccade frequency. In blocks with high antisaccade frequency, antisaccade latencies were shorter and error rates lower whilst prosaccade latencies were longer and error rates were higher. At the level of BOLD, activations in the task-related saccade network (left inferior parietal lobe, right inferior parietal sulcus, left precentral gyrus reaching into left middle frontal gyrus and inferior frontal junction) and deactivations in components of the default mode network (bilateral temporal cortex, ventromedial prefrontal cortex) compensated increased cognitive control demands. These findings illustrate context dependent mechanisms underlying the coordination of competing decision signals in volitional gaze control.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Thomaes2016,

title = {Degrading traumatic memories with eye movements: A pilot functional MRI study in PTSD},

author = {Kathleen Thomaes and Iris M. Engelhard and Marit Sijbrandij and Danielle C. Cath and Odile A. Heuvel},

doi = {10.3402/ejpt.v7.31371},

year  = {2016},

date = {2016-01-01},

journal = {European Journal of Psychotraumatology},

volume = {7},

number = {1},

pages = {1–10},

abstract = {Background: Eye movement desensitization and reprocessing (EMDR) is an effective treatment for post-traumatic stress disorder (PTSD). During EMDR, the patient recalls traumatic memories while making eye movements (EMs). Making EMs during recall is associated with decreased vividness and emotionality of traumatic memories, but the underlying mechanism has been unclear. Recent studies support a ''working-memory'' (WM) theory, which states that the two tasks (recall and EMs) compete for limited capacity of WM resources. However, prior research has mainly relied on self-report measures. Methods: Using functional magnetic resonance imaging, we tested whether ''recall with EMs,''relative to a ''recall-only'' control condition, was associated with reduced activity of primary visual and emotional processing brain regions, associatedwith vividness and emotionality respectively, and increased activity of the dorsolateral prefrontal cortex (DLPFC), associated with working memory. We used a randomized, controlled, crossover experimental design in eight adult patients with a primary diagnosis of PTSD. A script-driven imagery (SDI) procedure was used to measure responsiveness to an audio-script depicting the participant's traumatic memory before and after conditions. Results: SDI activated mainly emotional processing-related brain regions (anterior insula, rostral anterior cingulate cortex (ACC), and dorsomedial prefrontal cortex), WM-related (DLPFC), and visual (association) brain regions before both conditions. Although predicted pre-to post-test decrease in amygdala activation after "recall with EMs" was not significant, SDI activated less right amygdala and rostral ACC activity after "recall with EMs" compared to post-"recall-only." Furthermore, functional connectivity from the right amygdala to the rostral ACC was decreased after "recall with EMs" compared with after "recall-only." Conclusions: These preliminary results in a small sample suggest that making EMs during recall, which is part of the regular EMDR treatment protocol, might reduce activity and connectivity in emotional processing-related areas. This study warrants replication in a larger sample.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Brink2016,

title = {Catecholaminergic neuromodulation shapes intrinsic MRI functional connectivity in the human brain},

author = {Ruud L. Brink and Thomas Pfeffer and Christopher M. Warren and Peter R. Murphy and Klodiana-Daphne Tona and Nic J. Wee and Eric J. Giltay and Martijn S. Noorden and Serge A. R. B. Rombouts and Tobias H. Donner and Sander Nieuwenhuis},

doi = {10.1523/JNEUROSCI.0744-16.2016},

year  = {2016},

date = {2016-01-01},

journal = {Journal of Neuroscience},

volume = {36},

number = {30},

pages = {7865–7876},

abstract = {The brain commonly exhibits spontaneous (i.e., in the absence of a task) fluctuations in neural activity that are correlated across brain regions. It has been established that the spatial structure, or topography, of these intrinsic correlations is in part determined by the fixed anatomical connectivity between regions. However, it remains unclear which factors dynamically sculpt this topography as a function of brain state. Potential candidate factors are subcortical catecholaminergic neuromodulatory systems, such as the locus ceruleus-norepinephrine system, which send diffuse projections to most parts of the forebrain. Here, we systematically characterized the effects of endogenous central neuromodulation on correlated fluctuations during rest in the human brain. Using a double-blind placebo-controlled crossover design, we pharmacologically increased synaptic catecholamine levels by administering atomoxetine, an NE transporter blocker, and examined the effects on the strength and spatial structure of resting-state MRI functional connectivity. First, atomoxetine reduced the strength of inter-regional correlations across three levels of spatial organization, indicating that catecholamines reduce the strength of functional interactions during rest. Second, this modulatory effectonintrinsic correlations exhibited a substantial degree of spatial specificity: the decrease in functional connectivity showed an anterior–posterior gradient in the cortex, depended on the strength of baseline functional connectivity, and was strongest for connections between regions belonging to distinct resting-state networks. Thus, catecholamines reduce intrinsic correlations in a spatially heterogeneous fashion. We conclude that neuromodulation is an important factor shaping the topography of intrinsic functional connectivity.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dijk2016,

title = {Intersession reliability of population receptive field estimates},

author = {Jelle A. Dijk and Benjamin Haas and Christina Moutsiana and D. Samuel Schwarzkopf},

doi = {10.1016/j.neuroimage.2016.09.013},

year  = {2016},

date = {2016-01-01},

journal = {NeuroImage},

volume = {143},

pages = {293–303},

publisher = {Elsevier},

abstract = {Population receptive field (pRF) analysis is a popular method to infer spatial selectivity of voxels in visual cortex. However, it remains largely untested how stable pRF estimates are over time. Here we measured the intersession reliability of pRF parameter estimates for the central visual field and near periphery, using a combined wedge and ring stimulus containing natural images. Sixteen healthy human participants completed two scanning sessions separated by 10–114 days. Individual participants showed very similar visual field maps for V1-V4 on both sessions. Intersession reliability for eccentricity and polar angle estimates was close to ceiling for most visual field maps (r>.8 for V1-3). PRF size and cortical magnification (CMF) estimates showed strong but lower overall intersession reliability (r≈.4–.6). Group level results for pRF size and CMF were highly similar between sessions. Additional control experiments confirmed that reliability does not depend on the carrier stimulus used and that reliability for pRF size and CMF is high for sessions acquired on the same day (r>.6). Our results demonstrate that pRF mapping is highly reliable across sessions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Loon2016,

title = {NMDA receptor antagonist ketamine distorts object recognition by reducing feedback to early visual cortex},

author = {Anouk Mariette Loon and Johannes J. Fahrenfort and Bauke Velde and Philipp B. Lirk and Nienke C. C. Vulink and Markus W. Hollmann and H. Steven Scholte and Victor A. F. Lamme},

doi = {10.1093/cercor/bhv018},

year  = {2016},

date = {2016-01-01},

journal = {Cerebral Cortex},

volume = {26},

number = {5},

pages = {1986–1996},

abstract = {It is a well-established fact that top-down processes influence neural representations in lower-level visual areas. Electrophysiological recordings in monkeys as well as theoretical models suggest that these top-down processes depend on NMDA receptor functioning. However, this underlying neural mechanism has not been tested in humans. We used fMRI multivoxel pattern analysis to compare the neural representations of ambiguous Mooney images before and after they were recognized with their unambiguous grayscale version. Additionally, we administered ketamine, an NMDA receptor antagonist, to interfere with this process. Our results demonstrate that after recognition, the pattern of brain activation elicited by a Mooney image is more similar to that of its easily recognizable grayscale version than to the pattern evoked by the identical Mooney image before recognition. Moreover, recognition of Mooney images decreased mean response; however, neural representations of separate images became more dissimilar. So from the neural perspective, unrecognizable Mooney images all “look the same”, whereas recognized Mooneys look different. We observed these effects in posterior fusiform part of lateral occipital cortex and in early visual cortex. Ketamine distorted these effects of recognition, but in early visual cortex only. This suggests that top-down processes from higher- to lower-level visual areas might operate via an NMDA pathway.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Vandenbroucke2016,

title = {Prior knowledge about objects determines neural color representation in human visual cortex},

author = {Annelinde R. E. Vandenbroucke and Johannes J. Fahrenfort and Julia D. I. Meuwese and H. Steven Scholte and Victor A. F. Lamme},

doi = {10.1093/cercor/bhu224},

year  = {2016},

date = {2016-01-01},

journal = {Cerebral Cortex},

volume = {26},

number = {4},

pages = {1401–1408},

abstract = {To create subjective experience, our brain must translate physical stimulus input by incorporating prior knowledge and expectations. For example, we perceive color and not wavelength information, and this in part depends on our past experience with colored objects ( Hansen et al. 2006; Mitterer and de Ruiter 2008). Here, we investigated the influence of object knowledge on the neural substrates underlying subjective color vision. In a functional magnetic resonance imaging experiment, human subjects viewed a color that lay midway between red and green (ambiguous with respect to its distance from red and green) presented on either typical red (e.g., tomato), typical green (e.g., clover), or semantically meaningless (nonsense) objects. Using decoding techniques, we could predict whether subjects viewed the ambiguous color on typical red or typical green objects based on the neural response of veridical red and green. This shift of neural response for the ambiguous color did not occur for nonsense objects. The modulation of neural responses was observed in visual areas (V3, V4, VO1, lateral occipital complex) involved in color and object processing, as well as frontal areas. This demonstrates that object memory influences wavelength information relatively early in the human visual system to produce subjective color vision.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Visser2016,

title = {Quantifying learning-dependent changes in the brain: Single-trial multivoxel pattern analysis requires slow event-related fMRI},

author = {Renée M. Visser and Michelle I. C. Haan and Tinka Beemsterboer and Pia Haver and Merel Kindt and H. Steven Scholte},

doi = {10.1111/psyp.12665},

year  = {2016},

date = {2016-01-01},

journal = {Psychophysiology},

volume = {53},

number = {8},

pages = {1117–1127},

abstract = {Single-trial analysis is particularly useful for assessing cognitive processes that are intrinsically dynamic, such as learning. Studying these processes with fMRI is problematic, as the low signal-to-noise ratio of fMRI requires the averaging over multiple trials, obscuring trial-by-trial changes in neural activation. The superior sensitivity of multivoxel pattern analysis over univariate analyses has opened up new possibilities for single-trial analysis, but this may require different fMRI designs. Here, we measured fMRI and pupil dilation responses during discriminant aversive conditioning, to assess associative learning in a trial-by-trial manner. The impact of design choices was examined by varying trial spacing and trial order in a series of five experiments (total n = 66), while keeping stimulus duration constant (4.5 s). Our outcome measure was the change in similarity between neural response patterns related to two consecutive presentations of the same stimulus (within-stimulus) and between patterns related to pairs of different stimuli (between-stimulus) that shared a specific outcome (electric stimulation vs. no consequence). This trial-by-trial similarity analysis revealed clear single-trial learning curves in conditions with intermediate (8.1-12.6 s) and long (16.5-18.4 s) intervals, with effects being strongest in designs with long intervals and counterbalanced stimulus presentation. No learning curves were observed in designs with shorter intervals (1.6-6.1 s), indicating that rapid event-related designs-at present, the most common designs in fMRI research-are not suited for single-trial pattern analysis. These findings emphasize the importance of deciding on the type of analysis prior to data collection.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wang2016g,

title = {Coupling between theta oscillations and cognitive control network during cross-modal visual and auditory attention: Supramodal vs modality-specific mechanisms},

author = {Wuyi Wang and Shivakumar Viswanathan and Taraz Lee and Scott T. Grafton},

doi = {10.1371/journal.pone.0158465},

year  = {2016},

date = {2016-01-01},

journal = {PLoS ONE},

volume = {11},

number = {7},

pages = {e0158465},

abstract = {Cortical theta band oscillations (4-8 Hz) in EEG signals have been shown to be important for a variety of different cognitive control operations in visual attention paradigms. However the synchronization source of these signals as defined by fMRI BOLD activity and the extent to which theta oscillations play a role in multimodal attention remains unknown. Here we investigated the extent to which cross-modal visual and auditory attention impacts theta oscillations. Using a simultaneous EEG-fMRI paradigm, healthy human participants performed an attentional vigilance task with six cross-modal conditions using naturalistic stimuli. To assess supramodal mechanisms, modulation of theta oscillation amplitude for attention to either visual or auditory stimuli was correlated with BOLD activity by conjunction analysis. Negative correlation was localized to cortical regions associated with the default mode network and positively with ventral premotor areas. Modality-associated attention to visual stimuli was marked by a positive correlation of theta and BOLD activity in fronto-parietal area that was not observed in the auditory condition. A positive correlation of theta and BOLD activity was observed in auditory cortex, while a negative correlation of theta and BOLD activity was observed in visual cortex during auditory attention. The data support a supramodal interaction of theta activity with of DMN function, and modality-associated processes within fronto-parietal networks related to top-down theta related cognitive control in cross-modal visual attention. On the other hand, in sensory cortices there are opposing effects of theta activity during cross-modal auditory attention.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wang2016h,

title = {Dynamic network communication in the human functional connectome predicts perceptual variability in visual illusion},

author = {Zheng Zhiwei Wang and Kristina Zeljic and Qinying Jiang and Yong Gu and Wei Wang and Zheng Wang},

doi = {10.1093/cercor/bhw347},

year  = {2016},

date = {2016-01-01},

journal = {Cerebral Cortex},

volume = {28},

number = {1},

pages = {1–15},

abstract = {The eukaryotic RNA exosome is an essential, multi-subunit complex that catalyzes RNA turnover, maturation, and quality control processes. Its non-catalytic donut-shaped core includes 9 subunits that associate with the 3' to 5' exoribonucleases Rrp6, and Rrp44/Dis3, a subunit that also catalyzes endoribonuclease activity. Although recent structures and biochemical studies of RNA bound exosomes from S. cerevisiae revealed that the Exo9 central channel guides RNA to either Rrp6 or Rrp44 using partially overlapping and mutually exclusive paths, several issues related to RNA recruitment remain. Here, we identify activities for the highly basic Rrp6 C-terminal tail that we term the 'lasso' because it binds RNA and stimulates ribonuclease activities associated with Rrp44 and Rrp6 within the 11-subunit nuclear exosome. Stimulation is dependent on the Exo9 central channel, and the lasso contributes to degradation and processing activities of exosome substrates in vitro and in vivo. Finally, we present evidence that the Rrp6 lasso may be a conserved feature of the eukaryotic RNA exosome.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Warren2016,

title = {Catecholamine-mediated increases in gain enhance the precision of cortical representations},

author = {Christopher M. Warren and Eran Eldar and Ruud L. Brink and Klodiana-Daphne Tona and Nic J. Wee and Eric J. Giltay and Martijn S. Noorden and Jos A. Bosch and Robert C. Wilson and Jonathan D. Cohen and Sander Nieuwenhuis},

doi = {10.1523/JNEUROSCI.3475-15.2016},

year  = {2016},

date = {2016-01-01},

journal = {Journal of Neuroscience},

volume = {36},

number = {21},

pages = {5699–5708},

abstract = {Neurophysiological evidence suggests that neuromodulators, such as norepinephrine and dopamine, increase neural gain in target brain areas. Computational models and prominent theoretical frameworks indicate that this should enhance the precision of neural represen- tations, but direct empirical evidence for this hypothesis is lacking. In two functional MRI studies, we examine the effect of baseline catecholamine levels (as indexed by pupil diameter and manipulated pharmacologically) on the precision of object representations in the human ventral temporal cortex using angular dispersion, a powerful, multivariate metric of representational similarity (precision). We first report the results of computational model simulations indicating that increasing catecholaminergic gain should reduce the angular dispersion, and thus increase the precision, of object representations from the same category, as well as reduce the angular dispersion of object representations from distinct categories when distinct-category representations overlap. In Study 1 (N?24), we showthat angular dispersion covaries with pupil diameter, an index of baseline catecholamine levels. In Study 2 (N?24), we manipulate catecholamine levels and neural gain using the norepinephrine transporter blocker atomoxetine and demonstrate consistent, causal effects on angular dispersion and brain-wide functional connectivity. Despite the use of very different methods of examining the effect of baseline catecholamine levels, our results show a striking convergence and demonstrate that catecholamines increase the precision of neural representations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wilf2016,

title = {Diminished auditory responses during NREM sleep correlate with the hierarchy of language processing},

author = {Meytal Wilf and Michal Ramot and Edna Furman-Haran and Anat Arzi and Yechiel Levkovitz and Rafael Malach},

doi = {10.1371/journal.pone.0157143},

year  = {2016},

date = {2016-01-01},

journal = {PLoS ONE},

volume = {11},

number = {6},

pages = {e0157143},

abstract = {Natural sleep provides a powerful model system for studying the neuronal correlates of awareness and state changes in the human brain. To quantitatively map the nature of sleep-induced modulations in sensory responses we presented participants with auditory stimuli possessing different levels of linguistic complexity. Ten participants were scanned using functional magnetic resonance imaging (fMRI) during the waking state and after falling asleep. Sleep staging was based on heart rate measures validated independently on 20 participants using concurrent EEG and heart rate measurements and the results were confirmed using permutation analysis. Participants were exposed to three types of auditory stimuli: scrambled sounds, meaningless word sentences and comprehensible sentences. During non-rapid eye movement (NREM) sleep, we found diminishing brain activation along the hierarchy of language processing, more pronounced in higher processing regions. Specifically, the auditory thalamus showed similar activation levels during sleep and waking states, primary auditory cortex remained activated but showed a significant reduction in auditory responses during sleep, and the high order language-related representation in inferior frontal gyrus (IFG) cortex showed a complete abolishment of responses during NREM sleep. In addition to an overall activation decrease in language processing regions in superior temporal gyrus and IFG, those areas manifested a loss of semantic selectivity during NREM sleep. Our results suggest that the decreased awareness to linguistic auditory stimuli during NREM sleep is linked to diminished activity in high order processing stations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Astafiev2016,

title = {Exploring the physiological correlates of chronic mild traumatic brain injury symptoms},

author = {Serguei V. Astafiev and Kristina L. Zinn and Gordon L. Shulman and Maurizio Corbetta},

doi = {10.1016/j.nicl.2016.01.004},

year  = {2016},

date = {2016-01-01},

journal = {NeuroImage: Clinical},

volume = {11},

pages = {10–19},

publisher = {Elsevier},

abstract = {We report on the results of a multimodal imaging study involving behavioral assessments, evoked and resting-state BOLD fMRI, and DTI in chronic mTBI subjects. We found that larger task-evoked BOLD activity in the MT+/LO region in extra-striate visual cortex correlated with mTBI and PTSD symptoms, especially light sensitivity. Moreover, higher FA values near the left optic radiation (OR) were associated with both light sensitivity and higher BOLD activity in the MT+/LO region. The MT+/LO region was localized as a region of abnormal functional connectivity with central white matter regions previously found to have abnormal physiological signals during visual eye movement tracking (Astafiev et al., 2015). We conclude that mTBI symptoms and light sensitivity may be related to excessive responsiveness of visual cortex to sensory stimuli. This abnormal sensitivity may be related to chronic remodeling of white matter visual pathways acutely injured.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Brissenden2016,

title = {Functional evidence for a cerebellar node of the dorsal attention network},

author = {James A. Brissenden and Emily J. Levin and David E. Osher and Mark A. Halko and David C. Somers},

doi = {10.1523/JNEUROSCI.0344-16.2016},

year  = {2016},

date = {2016-01-01},

journal = {Journal of Neuroscience},

volume = {36},

number = {22},

pages = {6083–6096},

abstract = {The "dorsal attention network" or "frontoparietal network" refers to a network of cortical regions that support sustained attention and working memory. Recent work has demonstrated that cortical nodes of the dorsal attention network possess intrinsic functional connections with a region in ventral cerebellum, in the vicinity of lobules VII/VIII. Here, we performed a series of task-based and resting-state fMRI experiments to investigate cerebellar participation in the dorsal attention network in humans. We observed that visual working memory and visual attention tasks robustly recruit cerebellar lobules VIIb and VIIIa, in addition to canonical cortical dorsal attention network regions. Across the cerebellum, resting-state functional connectivity with the cortical dorsal attention network strongly predicted the level of activation produced by attention and working memory tasks. Critically, cerebellar voxels that were most strongly connected with the dorsal attention network selectively exhibited load-dependent activity, a hallmark of the neural structures that support visual working memory. Finally, we examined intrinsic functional connectivity between task-responsive portions of cerebellar lobules VIIb/VIIIa and cortex. Cerebellum-to-cortex functional connectivity strongly predicted the pattern of cortical activation during task performance. Moreover, resting-state connectivity patterns revealed that cerebellar lobules VIIb/VIIIa group with cortical nodes of the dorsal attention network. This evidence leads us to conclude that the conceptualization of the dorsal attention network should be expanded to include cerebellar lobules VIIb/VIIIa.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Choo2016,

title = {Contour junctions underlie neural representations of scene categories in high-level human visual cortex: Contour junctions underlie neural representations of scenes},

author = {Heeyoung Choo and Dirk B. Walther},

doi = {10.1016/j.neuroimage.2016.04.021},

year  = {2016},

date = {2016-01-01},

journal = {NeuroImage},

volume = {135},

pages = {32–44},

publisher = {Elsevier Inc.},

abstract = {Humans efficiently grasp complex visual environments, making highly consistent judgments of entry-level category despite their high variability in visual appearance. How does the human brain arrive at the invariant neural representations underlying categorization of real-world environments? We here show that the neural representation of visual environments in scene-selective human visual cortex relies on statistics of contour junctions, which provide cues for the three-dimensional arrangement of surfaces in a scene. We manipulated line drawings of real-world environments such that statistics of contour orientations or junctions were disrupted. Manipulated and intact line drawings were presented to participants in an fMRI experiment. Scene categories were decoded from neural activity patterns in the parahippocampal place area (PPA), the occipital place area (OPA) and other visual brain regions. Disruption of junctions but not orientations led to a drastic decrease in decoding accuracy in the PPA and OPA, indicating the reliance of these areas on intact junction statistics. Accuracy of decoding from early visual cortex, on the other hand, was unaffected by either image manipulation. We further show that the correlation of error patterns between decoding from the scene-selective brain areas and behavioral experiments is contingent on intact contour junctions. Finally, a searchlight analysis exposes the reliance of visually active brain regions on different sets of contour properties. Statistics of contour length and curvature dominate neural representations of scene categories in early visual areas and contour junctions in high-level scene-selective brain regions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Desai2016,

title = {Toward semantics in the wild: Activation to manipulable nouns in naturalistic reading},

author = {Rutvik H. Desai and Wonil Choi and Vicky T. Lai and John M. Henderson},

doi = {10.1523/JNEUROSCI.1480-15.2016},

year  = {2016},

date = {2016-01-01},

journal = {Journal of Neuroscience},

volume = {36},

number = {14},

pages = {4050–4055},

abstract = {The neural basis of language processing, in the context of naturalistic reading of connected text, is a crucial but largely unexplored area. Here we combined functional MRI and eye tracking to examine the reading of text presented as whole paragraphs in two experiments with human subjects. We registered high-temporal resolution eye-tracking data to a low-temporal resolution BOLD signal to extract responses to single words during naturalistic reading where two to four words are typically processed per second. As a test case of a lexical variable, we examined the response to noun manipulability. In both experiments, signal in the left anterior inferior parietal lobule and posterior inferior temporal gyrus and sulcus was positively correlated with noun manipulability. These regions are associated with both action performance and action semantics, and their activation is consistent with a number of previous studies involving tool words and physical tool use. The results show that even during rapid reading of connected text, where semantics of words may be activated only partially, the meaning of manipulable nouns is grounded in action performance systems. This supports the grounded cognition view of semantics, which posits a close link between sensory-motor and conceptual systems of the brain. On the methodological front, these results demonstrate that BOLD responses to lexical variables during naturalistic reading can be extracted by simultaneous use of eye tracking. This opens up new avenues for the study of language and reading in the context of connected text.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dombert2016a,

title = {Functional mechanisms of probabilistic inference in feature- and space-based attentional systems},

author = {Pascasie L. Dombert and Anna B. Kuhns and Paola Mengotti and Gereon R. Fink and Simone Vossel},

doi = {10.1016/j.neuroimage.2016.08.010},

year  = {2016},

date = {2016-01-01},

journal = {NeuroImage},

volume = {142},

pages = {553–564},

publisher = {Elsevier Inc.},

abstract = {Humans flexibly attend to features or locations and these processes are influenced by the probability of sensory events. We combined computational modeling of response times with fMRI to compare the functional correlates of (re-)orienting, and the modulation by probabilistic inference in spatial and feature-based attention systems. Twenty-four volunteers performed two task versions with spatial or color cues. Percentage of cue validity changed unpredictably. A hierarchical Bayesian model was used to derive trial-wise estimates of probability-dependent attention, entering the fMRI analysis as parametric regressors. Attentional orienting activated a dorsal frontoparietal network in both tasks, without significant parametric modulation. Spatially invalid trials activated a bilateral frontoparietal network and the precuneus, while invalid feature trials activated the left intraparietal sulcus (IPS). Probability-dependent attention modulated activity in the precuneus, left posterior IPS, middle occipital gyrus, and right temporoparietal junction for spatial attention, and in the left anterior IPS for feature-based and spatial attention. These findings provide novel insights into the generality and specificity of the functional basis of attentional control. They suggest that probabilistic inference can distinctively affect each attentional subsystem, but that there is an overlap in the left IPS, which responds to both spatial and feature-based expectancy violations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zimmer2016,

title = {Neuronal interactions in areas of spatial attention reflect avoidance of disgust, but orienting to danger},

author = {Ulrike Zimmer and M H"ofler and Karl Koschutnig and Anja Ischebeck and Margit Höfler and Karl Koschutnig and Anja Ischebeck},

doi = {10.1016/j.neuroimage.2016.03.050},

year  = {2016},

date = {2016-01-01},

journal = {NeuroImage},

volume = {134},

pages = {94–104},

abstract = {For survival, it is necessary to attend quickly towards dangerous objects, but to turn away from something that is disgusting. We tested whether fear and disgust sounds direct spatial attention differently. Using fMRI, a sound cue (disgust, fear or neutral) was presented to the left or right ear. The cue was followed by a visual target (a small arrow) which was located on the same (valid) or opposite (invalid) side as the cue. Participants were required to decide whether the arrow pointed up- or downwards while ignoring the sound cue. Behaviorally, responses were faster for invalid compared to valid targets when cued by disgust, whereas the opposite pattern was observed for targets after fearful and neutral sound cues. During target presentation, activity in the visual cortex and IPL increased for targets invalidly cued with disgust, but for targets validly cued with fear which indicated a general modulation of activation due to attention. For the TPJ, an interaction in the opposite direction was observed, consistent with its role in detecting targets at unattended positions and in relocating attention. As a whole our results indicate that a disgusting sound directs spatial attention away from its location, in contrast to fearful and neutral sounds.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zimmermann2016b,

title = {Spatiotopic adaptation in visual areas},

author = {Eckart Zimmermann and Ralph Weidner and R. O. Abdollahi and Gereon R. Fink},

doi = {10.1523/JNEUROSCI.0052-16.2016},

year  = {2016},

date = {2016-01-01},

journal = {Journal of Neuroscience},

volume = {36},

number = {37},

pages = {9526–9534},

abstract = {The ability to perceive the visual world around us as spatially stable despite frequent eye movements is one of the long-standing mysteries of neuroscience. The existence of neural mechanisms processing spatiotopic information is indispensable for a successful interaction with the external world. However, how the brain handles spatiotopic information remains a matter of debate. We here combined behavioral and fMRI adaptation to investigate the coding of spatiotopic information in the human brain. Subjects were adapted by a prolonged presentation of a tilted grating. Thereafter, they performed a saccade followed by the brief presentation of a probe. This procedure allowed dissociating adaptation aftereffects at retinal and spatiotopic positions. We found significant behavioral and functional adaptation in both retinal and spatiotopic positions, indicating information transfer into a spatiotopic coordinate system. The brain regions involved were located in ventral visual areas V3, V4, and VO. Our findings suggest that spatiotopic representations involved in maintaining visual stability are constructed by dynamically remapping visual feature information between retinotopic regions within early visual areas.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Adams2016,

title = {Dynamic causal modelling of eye movements during pursuit: Confirming precision-encoding in V1 using MEG},

author = {Rick A. Adams and Markus Bauer and Dimitris Pinotsis and Karl J. Friston},

doi = {10.1016/j.neuroimage.2016.02.055},

year  = {2016},

date = {2016-01-01},

journal = {Neuroimage},

volume = {132},

pages = {175–189},

publisher = {The Authors},

abstract = {This paper shows that it is possible to estimate the subjective precision (inverse variance) of Bayesian beliefs during oculomotor pursuit. Subjects viewed a sinusoidal target, with or without random fluctuations in its motion. Eye trajectories and magnetoencephalographic (MEG) data were recorded concurrently. The target was periodically occluded, such that its reappearance caused a visual evoked response field (ERF). Dynamic causal modelling (DCM) was used to fit models of eye trajectories and the ERFs. The DCM for pursuit was based on predictive coding and active inference, and predicts subjects' eye movements based on their (subjective) Bayesian beliefs about target (and eye) motion. The precisions of these hierarchical beliefs can be inferred from behavioural (pursuit) data. The DCM for MEG data used an established biophysical model of neuronal activity that includes parameters for the gain of superficial pyramidal cells, which is thought to encode precision at the neuronal level. Previous studies (using DCM of pursuit data) suggest that noisy target motion increases subjective precision at the sensory level: i.e., subjects attend more to the target's sensory attributes. We compared (noisy motion-induced) changes in the synaptic gain based on the modelling of MEG data to changes in subjective precision estimated using the pursuit data. We demonstrate that imprecise target motion increases the gain of superficial pyramidal cells in V1 (across subjects). Furthermore, increases in sensory precision – inferred by our behavioural DCM – correlate with the increase in gain in V1, across subjects. This is a step towards a fully integrated model of brain computations, cortical responses and behaviour that may provide a useful clinical tool in conditions like schizophrenia.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{BaboRebelo2016,

title = {Neural responses to heartbeats in the default network encode the self in spontaneous thoughts},

author = {Mariana Babo-Rebelo and Craig G. Richter and Catherine Tallon-Baudry},

doi = {10.1523/JNEUROSCI.0262-16.2016},

year  = {2016},

date = {2016-01-01},

journal = {Journal of Neuroscience},

volume = {36},

number = {30},

pages = {7829–7840},

abstract = {The default network (DN) has been consistently associated with self-related cognition, but also to bodily state monitoring and autonomic regulation. We hypothesized that these two seemingly disparate functional roles of the DN are functionally coupled, in line with theories proposing that selfhood is grounded in the neural monitoring of internal organs, such as the heart. We measured with magnetoencephalograhy neural responses evoked by heartbeats while human participants freely mind-wandered. When interrupted by a visual stimulus at random intervals, participants scored the self-relatedness of the interrupted thought. They evaluated their involvement as the first-person perspective subject or agent in the thought ("I"), and on another scale to what degree they were thinking about themselves ("Me"). During the interrupted thought, neural responses to heartbeats in two regions of the DN, the ventral precuneus and the ventromedial prefrontal cortex, covaried, respectively, with the "I" and the "Me" dimensions of the self, even at the single-trial level. No covariation between self-relatedness and peripheral autonomic measures (heart rate, heart rate variability, pupil diameter, electrodermal activity, respiration rate, and phase) or alpha power was observed. Our results reveal a direct link between selfhood and neural responses to heartbeats in the DN and thus directly support theories grounding selfhood in the neural monitoring of visceral inputs. More generally, the tight functional coupling between self-related processing and cardiac monitoring observed here implies that, even in the absence of measured changes in peripheral bodily measures, physiological and cognitive functions have to be considered jointly in the DN.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Campana2016,

title = {Conscious vision proceeds from global to local content in goal-directed tasks and spontaneous vision},

author = {Florence Campana and Ignacio Rebollo and Anne E. Urai and Valentin Wyart and Catherine Tallon-Baudry},

doi = {10.1523/JNEUROSCI.3619-15.2016},

year  = {2016},

date = {2016-01-01},

journal = {Journal of Neuroscience},

volume = {36},

number = {19},

pages = {5200–5213},

abstract = {The reverse hierarchy theory (Hochstein and Ahissar, 2002) makes strong, but so far untested, predictions on conscious vision. In this theory, local details encoded in lower-order visual areas are unconsciously processed before being automatically and rapidly combined into global information in higher-order visual areas, where conscious percepts emerge. Contingent on current goals, local details can afterward be consciously retrieved. This model therefore predicts that (1) global information is perceived faster than local details, (2) global information is computed regardless of task demands during early visual processing, and (3) spontaneous vision is dominated by global percepts. We designed novel textured stimuli that are, as opposed to the classic Navon's letters, truly hierarchical (i.e., where global information is solely defined by local information but where local and global orientations can still be manipulated separately). In line with the predictions, observers were systematically faster reporting global than local properties of those stimuli. Second, global information could be decoded from magneto-encephalographic data during early visual processing regardless of task demands. Last, spontaneous subjective reports were dominated by global information and the frequency and speed of spontaneous global perception correlated with the accuracy and speed in the global task. No such correlation was observed for local information. We therefore show that information at different levels of the visual hierarchy is not equally likely to become conscious; rather, conscious percepts emerge preferentially at a global level. We further show that spontaneous reports can be reliable and are tightly linked to objective performance at the global level.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Godier2016,

title = {Enhanced early neuronal processing of food pictures in Anorexia Nervosa: A magnetoencephalography study},

author = {Lauren R. Godier and Jessica C. Scaife and Sven Braeutigam and Rebecca J. Park},

doi = {10.1155/2016/1795901},

year  = {2016},

date = {2016-01-01},

journal = {Psychiatry Journal},

volume = {2016},

pages = {1–13},

abstract = {Neuroimaging studies in Anorexia Nervosa (AN) have shown increased activation in reward and cognitive control regions in response to food, and a behavioral attentional bias (AB) towards food stimuli is reported. This study aimed to further investigate the neural processing of food using magnetoencephalography (MEG). Participants were 13 females with restricting-type AN, 14 females recovered from restricting-type AN, and 15 female healthy controls. MEG data was acquired whilst participants viewed high- and low-calorie food pictures. Attention was assessed with a reaction time task and eye tracking. Time-series analysis suggested increased neural activity in response to both calorie conditions in the AN groups, consistent with an early AB. Increased activity was observed at 150 ms in the current AN group. Neuronal activity at this latency was at normal level in the recovered group; however, this group exhibited enhanced activity at 320 ms after stimulus. Consistent with previous studies, analysis in source space and behavioral data suggested enhanced attention and cognitive control processes in response to food stimuli in AN. This may enable avoidance of salient food stimuli and maintenance of dietary restraint in AN. A later latency of increased activity in the recovered group may reflect a reversal of this avoidance, with source space and behavioral data indicating increased visual and cognitive processing of food stimuli.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gregory2016a,

title = {Gamma frequency and the spatial tuning of primary visual cortex},

author = {Sarah Gregory and Marco Fusca and Geraint Rees and D. Samuel Schwarzkopf and Gareth Barnes},

doi = {10.1371/journal.pone.0157374},

year  = {2016},

date = {2016-01-01},

journal = {PLoS ONE},

volume = {11},

number = {6},

pages = {e0157374},

abstract = {Visual stimulation produces oscillatory gamma responses in human primary visual cortex (V1) that also relate to visual perception. We have shown previously that peak gamma frequency positively correlates with central V1 cortical surface area. We hypothesized that people with larger V1 would have smaller receptive fields and that receptive field size, not V1 are, might explain this relationship. Here we set out to test this hypothesis directly by investigating the relationship between fMRI estimated population receptive field (pRF) size and gamma frequency in V1. We stimulated both the near-centre and periphery of the visual field using both large and small stimuli in each location and replicated our previous finding of a positive correlation between V1 surface area and peak gamma frequency. Counter to our expectation, we found that between participants V1 size (and not pRF size) accounted for most of the variability in gamma frequency. Within-participants we found that gamma frequency increased, rather than decreased, with stimulus eccentricity directly contradicting our initial hypothesis.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ikkai2016,

title = {Lateralization in alpha-band oscillations predicts the locus and spatial distribution of attention},

author = {Akiko Ikkai and Sangita Dandekar and Clayton E. Curtis},

doi = {10.1371/journal.pone.0154796},

year  = {2016},

date = {2016-01-01},

journal = {PLoS ONE},

volume = {11},

number = {5},

pages = {e0154796},

abstract = {Attending to a task-relevant location changes how neural activity oscillates in the alpha band (8-13Hz) in posterior visual cortical areas. However, a clear understanding of the relationships between top-down attention, changes in alpha oscillations in visual cortex, and attention performance are still poorly understood. Here, we tested the degree to which the posterior alpha power tracked the locus of attention, the distribution of attention, and how well the topography of alpha could predict the locus of attention. We recorded magnetoencephalographic (MEG) data while subjects performed an attention demanding visual discrimination task that dissociated the direction of attention from the direction of a saccade to indicate choice. On some trials, an endogenous cue predicted the target's location, while on others it contained no spatial information. When the target's location was cued, alpha power decreased in sensors over occipital cortex contralateral to the attended visual field. When the cue did not predict the target's location, alpha power again decreased in sensors over occipital cortex, but bilaterally, and increased in sensors over frontal cortex. Thus, the distribution and the topography of alpha reliably indicated the locus of covert attention. Together, these results suggest that alpha synchronization reflects changes in the excitability of populations of neurons whose receptive fields match the locus of attention. This is consistent with the hypothesis that alpha oscillations reflect the neural mechanisms by which top-down control of attention biases information processing and modulate the activity of neurons in visual cortex.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marshall2016,

title = {On the relationship between cortical excitability and visual oscillatory responses-A concurrent tDCS-MEG study},

author = {Tom R. Marshall and Sophie Esterer and Jim D. Herring and Til O. Bergmann and Ole Jensen},

doi = {10.1016/j.neuroimage.2015.09.069},

year  = {2016},

date = {2016-01-01},

journal = {NeuroImage},

volume = {140},

pages = {41–49},

publisher = {Elsevier Inc.},

abstract = {Neuronal oscillations in the alpha band (8–12 Hz) in visual cortex are considered to instantiate ‘attentional gating' via the inhibition of activity in regions representing task-irrelevant parts of space. In contrast, visual gamma-band activity (40–100 Hz) is regarded as representing a bottom-up drive from incoming visual information, with increased synchronisation producing a stronger feedforward impulse for relevant information. However, little is known about the direct relationship between excitability of the visual cortex and these oscillatory mechanisms. In this study we used transcranial direct current stimulation (tDCS) in an Oz–Cz montage in order to stimulate visual cortex, concurrently recording whole-brain oscillatory activity using magnetoencephalography (MEG) whilst participants performed a visual task known to produce strong modulations of alpha- and gamma-band activity. We found that visual stimuli produced expected modulations of alpha and gamma – presenting a moving annulus stimulus led to a strong gamma increase and alpha decrease – and that this pattern was observable both during active (anodal and cathodal) tDCS and sham tDCS. However, tDCS did not seem to produce systematic alterations of these oscillatory responses. The present study thus demonstrates that concurrent tDCS/MEG of the visual system is a feasible tool for investigating visual neuronal oscillations, and we discuss potential reasons for the apparent inability of tDCS to effectively change the amplitude of visual stimulus induced oscillatory responses in the current study.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mok2016,

title = {Behavioral and neural markers of flexible attention over working memory in aging},

author = {Robert M. Mok and Nicholas E. Myers and George Wallis and Anna C. Nobre},

doi = {10.1093/cercor/bhw011},

year  = {2016},

date = {2016-01-01},

journal = {Cerebral Cortex},

volume = {26},

number = {4},

pages = {1831–1842},

abstract = {Working memory (WM) declines as we age and, because of its fundamental role in higher order cognition, this can have highly deleterious effects in daily life. We investigated whether older individuals benefit from flexible orienting of attention within WM to mitigate cognitive decline. We measured magnetoencephalography (MEG) in older adults performing a WM precision task with cues during the maintenance period that retroactively predicted the location of the relevant items for performance (retro-cues). WM performance of older adults significantly benefitted from retro-cues. Whereas WM maintenance declined with age, retro-cues conferred strong attentional benefits. A model-based analysis revealed an increase in the probability of recalling the target, a lowered probability of retrieving incorrect items or guessing, and an improvement in memory precision. MEG recordings showed that retro-cues induced a transient lateralization of alpha (8-14 Hz) and beta (15-30 Hz) oscillatory power. Interestingly, shorter durations of alpha/beta lateralization following retro-cues predicted larger cueing benefits, reinforcing recent ideas about the dynamic nature of access to WM representations. Our results suggest that older adults retain flexible control over WM, but individual differences in control correspond to differences in neural dynamics, possibly reflecting the degree of preservation of control in healthy aging.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ferri2016,

title = {Emotion regulation and amygdala-precuneus connectivity: Focusing on attentional deployment},

author = {Jamie Ferri and Joseph Schmidt and Greg Hajcak and Turhan Canli},

doi = {10.3758/s13415-016-0447-y},

year  = {2016},

date = {2016-01-01},

journal = {Cognitive, Affective, & Behavioral Neuroscience},

volume = {16},

number = {6},

pages = {991–1002},

publisher = {Cognitive, Affective, & Behavioral Neuroscience},

abstract = {Attentional deployment is an emotion regulation strategy that involves shifting attentional focus. Deploying attention to non-arousing, compared to arousing, regions of unpleasant images has been associated with reduced negative affect, reduced amygdala activation, and increased activity in fronto-parietal control networks. The current study examined neural correlates and functional connectivity associated with using attentional deployment to increase negative affect (deploying attention towards arousing unpleasant information) or to decrease negative affect (deploying attention away from arousing unpleasant information), compared to naturally viewing unpleasant images, in 42 individuals while concurrently monitoring eye movements. Directing attention to both arousing and non-arousing regions resulted in enhanced fronto-parietal activation compared to natural viewing, but only directing attention to non-arousing regions was associated with changes in amygdala activation. There were no significant differences in connectivity between naturally viewing unpleasant images and focusing on arousing regions. However, naturally viewing unpleasant images, relative to focusing on non-arousing regions, was associated with increased connectivity between the amygdala and visual cortex, while focusing on non-arousing regions of unpleasant images, compared to natural viewing, was associated with increased connectivity between the amygdala and the precuneus. Amygdala-precuneus connectivity correlated positively with eye-tracking measures of attentional deployment success and with trait reappraisal. Deploying attention away from arousing unpleasant information, then, may depend upon functional relationships between the amygdala and parietal regions implicated in attentional control. Furthermore, these relationships might relate to the ability to successfully implement attentional deployment, and the predisposition to utilize adaptive emotion regulation strategies.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Fraessle2016,

title = {Handedness is related to neural mechanisms underlying hemispheric lateralization of face processing},

author = {Stefan Frässle and Sören Krach and Frieder M. Paulus and Andreas Jansen},

doi = {10.1038/srep27153},

year  = {2016},

date = {2016-01-01},

journal = {Scientific Reports},

volume = {6},

pages = {27153},

publisher = {Nature Publishing Group},

abstract = {While the right-hemispheric lateralization of the face perception network is well established, recent evidence suggests that handedness affects the cerebral lateralization of face processing at the hierarchical level of the fusiform face area (FFA). However, the neural mechanisms underlying differential hemispheric lateralization of face perception in right- and left-handers are largely unknown. Using dynamic causal modeling (DCM) for fMRI, we aimed to unravel the putative processes that mediate handedness-related differences by investigating the effective connectivity in the bilateral core face perception network. Our results reveal an enhanced recruitment of the left FFA in left-handers compared to right-handers, as evidenced by more pronounced face-specific modulatory influences on both intra- and interhemispheric connections. As structural and physiological correlates of handedness- related differences in face processing, right- and left-handers varied with regard to their gray matter volume in the left fusiform gyrus and their pupil responses to face stimuli. Overall, these results describe how handedness is related to the lateralization of the core face perception network, and point to different neural mechanisms underlying face processing in right- and left-handers. In a wider context, this demonstrates the entanglement of structurally and functionally remote brain networks, suggesting a broader underlying process regulating brain lateralization.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Fraessle2016a,

title = {Mechanisms of hemispheric lateralization: Asymmetric interhemispheric recruitment in the face perception network},

author = {Stefan Frässle and Frieder M. Paulus and Sören Krach and Stefan Robert Schweinberger and Klaas Enno Stephan and Andreas Jansen},

doi = {10.1016/j.neuroimage.2015.09.055},

year  = {2016},

date = {2016-01-01},

journal = {NeuroImage},

volume = {124},

pages = {977–988},

publisher = {Elsevier Inc.},

abstract = {Perceiving human faces constitutes a fundamental ability of the human mind, integrating a wealth of information essential for social interactions in everyday life. Neuroimaging studies have unveiled a distributed neural network consisting of multiple brain regions in both hemispheres. Whereas the individual regions in the face perception network and the right-hemispheric dominance for face processing have been subject to intensive research, the functional integration among these regions and hemispheres has received considerably less attention. Using dynamic causal modeling (DCM) for fMRI, we analyzed the effective connectivity between the core regions in the face perception network of healthy humans to unveil the mechanisms underlying both intra- and interhemispheric integration. Our results suggest that the right-hemispheric lateralization of the network is due to an asymmetric face-specific interhemispheric recruitment at an early processing stage - that is, at the level of the occipital face area (OFA) but not the fusiform face area (FFA). As a structural correlate, we found that OFA gray matter volume was correlated with this asymmetric interhemispheric recruitment. Furthermore, exploratory analyses revealed that interhemispheric connection asymmetries were correlated with the strength of pupil constriction in response to faces, a measure with potential sensitivity to holistic (as opposed to feature-based) processing of faces. Overall, our findings thus provide a mechanistic description for lateralized processes in the core face perception network, point to a decisive role of interhemispheric integration at an early stage of face processing among bilateral OFA, and tentatively indicate a relation to individual variability in processing strategies for faces. These findings provide a promising avenue for systematic investigations of the potential role of interhemispheric integration in future studies.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gertz2016,

title = {Violating instructed human agency: An fMRI study on ocular tracking of biological and nonbiological motion stimuli},

author = {Hanna Gertz and Maximilian Hilger and Mathias Hegele and Katja Fiehler},

doi = {10.1016/j.neuroimage.2016.05.043},

year  = {2016},

date = {2016-01-01},

journal = {NeuroImage},

volume = {138},

pages = {109–122},

publisher = {Elsevier Inc.},

abstract = {Previous studies have shown that beliefs about the human origin of a stimulus are capable of modulating the coupling of perception and action. Such beliefs can be based on top-down recognition of the identity of an actor or bottom-up observation of the behavior of the stimulus. Instructed human agency has been shown to lead to superior tracking performance of a moving dot as compared to instructed computer agency, especially when the dot followed a biological velocity profile and thus matched the predicted movement, whereas a violation of instructed human agency by a nonbiological dot motion impaired oculomotor tracking (Zwickel et al., 2012). This suggests that the instructed agency biases the selection of predictive models on the movement trajectory of the dot motion. The aim of the present fMRI study was to examine the neural correlates of top-down and bottom-up modulations of perception–action couplings by manipulating the instructed agency (human action vs. computer-generated action) and the observable behavior of the stimulus (biological vs. nonbiological velocity profile). To this end, participants performed an oculomotor tracking task in an MRI environment. Oculomotor tracking activated areas of the eye movement network. A right-hemisphere occipito-temporal cluster comprising the motion-sensitive area V5 showed a preference for the biological as compared to the nonbiological velocity profile. Importantly, a mismatch between instructed human agency and a nonbiological velocity profile primarily activated medial–frontal areas comprising the frontal pole, the paracingulate gyrus, and the anterior cingulate gyrus, as well as the cerebellum and the supplementary eye field as part of the eye movement network. This mismatch effect was specific to the instructed human agency and did not occur in conditions with a mismatch between instructed computer agency and a biological velocity profile. Our results support the hypothesis that humans activate a specific predictive model for biological movements based on their own motor expertise. A violation of this predictive model causes costs as the movement needs to be corrected in accordance with incoming (nonbiological) sensory information.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gonzalez2016a,

title = {The involvement of the fronto-parietal brain network in oculomotor sequence learning using fMRI},

author = {Claudia C. Gonzalez and Jac Billington and Melanie R. Burke},

doi = {10.1016/j.neuropsychologia.2016.04.021},

year  = {2016},

date = {2016-01-01},

journal = {Neuropsychologia},

volume = {87},

pages = {1–11},

publisher = {Elsevier},

abstract = {The basis of motor learning involves decomposing complete actions into a series of predictive individual components that form the whole. The present fMRI study investigated the areas of the human brain important for oculomotor short-term learning, by using a novel sequence learning paradigm that is equivalent in visual and temporal properties for both saccades and pursuit, enabling more direct comparisons between the oculomotor subsystems. In contrast with previous studies that have implemented a series of discrete ramps to observe predictive behaviour as evidence for learning, we presented a continuous sequence of interlinked components that better represents sequences of actions. We implemented both a classic univariate fMRI analysis, followed by a further multivariate pattern analysis (MVPA) within a priori regions of interest, to investigate oculomotor sequence learning in the brain and to determine whether these mechanisms overlap in pursuit and saccades as part of a higher order learning network. This study has uniquely identified an equivalent frontal-parietal network (dorsolateral prefrontal cortex, frontal eye fields and posterior parietal cortex) in both saccades and pursuit sequence learning. In addition, this is the first study to investigate oculomotor sequence learning during fMRI brain imaging, and makes significant contributions to understanding the role of the dorsal networks in motor learning.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hanke2016,

title = {A studyforrest extension, simultaneous fMRI and eye gaze recordings during prolonged natural stimulation},

author = {Michael Hanke and Nico Adelhöfer and Daniel Kottke and Vittorio Iacovella and Ayan Sengupta and Falko R. Kaule and Roland Nigbur and Alexander Q. Waite and Florian Baumgartner and Jörg Stadler},

doi = {10.1038/sdata.2016.92},

year  = {2016},

date = {2016-01-01},

journal = {Scientific Data},

volume = {3},

pages = {160092},

abstract = {Here we present an update of the studyforrest (http://studyforrest.org) dataset that complements the previously released functional magnetic resonance imaging (fMRI) data for natural language processing with a new two-hour 3 Tesla fMRI acquisition while 15 of the original participants were shown an audio-visual version of the stimulus motion picture. We demonstrate with two validation analyses that these new data support modeling specific properties of the complex natural stimulus, as well as a substantial within-subject BOLD response congruency in brain areas related to the processing of auditory inputs, speech, and narrative when compared to the existing fMRI data for audio-only stimulation. In addition, we provide participants' eye gaze location as recorded simultaneously with fMRI, and an additional sample of 15 control participants whose eye gaze trajectories for the entire movie were recorded in a lab setting-to enable studies on attentional processes and comparative investigations on the potential impact of the stimulation setting on these processes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Henderson2016,

title = {Language structure in the brain: A fixation-related fMRI study of syntactic surprisal in reading},

author = {John M. Henderson and Wonil Choi and Matthew W. Lowder and Fernanda Ferreira},

doi = {10.1016/j.neuroimage.2016.02.050},

year  = {2016},

date = {2016-01-01},

journal = {NeuroImage},

volume = {132},

pages = {293–300},

publisher = {Elsevier Inc.},

abstract = {How is syntactic analysis implemented by the human brain during language comprehension? The current study combined methods from computational linguistics, eyetracking, and fMRI to address this question. Subjects read passages of text presented as paragraphs while their eye movements were recorded in an MRI scanner. We parsed the text using a probabilistic context-free grammar to isolate syntactic difficulty. Syntactic difficulty was quantified as syntactic surprisal, which is related to the expectedness of a given word's syntactic category given its preceding context. We compared words with high and low syntactic surprisal values that were equated for length, frequency, and lexical surprisal, and used fixation-related (FIRE) fMRI to measure neural activity associated with syntactic surprisal for each fixated word. We observed greater neural activity for high than low syntactic surprisal in two predicted cortical regions previously identified with syntax: left inferior frontal gyrus (IFG) and less robustly, left anterior superior temporal lobe (ATL). These results support the hypothesis that left IFG and ATL play a central role in syntactic analysis during language comprehension. More generally, the results suggest a broader cortical network associated with syntactic prediction that includes increased activity in bilateral IFG and insula, as well as fusiform and right lingual gyri.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hummer2016,

title = {Eye tracker-based gaze correction for robust mapping of population receptive fields},

author = {A. Hummer and M. Ritter and M. Tik and A. A. Ledolter and M. Woletz and G. E. Holder and Serge O. Dumoulin and U. Schmidt-Erfurth and C. Windischberger},

doi = {10.1016/j.neuroimage.2016.07.003},

year  = {2016},

date = {2016-01-01},

journal = {NeuroImage},

volume = {142},

pages = {211–224},

publisher = {Elsevier B.V.},

abstract = {Functional MRI enables the acquisition of a retinotopic map that relates regions of the visual field to neural populations in the visual cortex. During such a “population receptive field” (PRF) experiment, stable gaze fixation is of utmost importance in order to correctly link the presented stimulus patterns to stimulated retinal regions and the resulting Blood Oxygen Level Dependent (BOLD) response of the appropriate region within the visual cortex. A method is described that compensates for unstable gaze fixation by recording gaze position via an eyetracker and subsequently modifies the input stimulus underlying the PRF analysis according to the eyetracking measures. Here we show that PRF maps greatly improve when the method is applied to data acquired with either saccadic or smooth eye movements. We conclude that the technique presented herein is useful for studies involving subjects with unstable gaze fixation, particularly elderly patient populations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Intaite2016,

title = {Working memory load influences perceptual ambiguity by competing for fronto-parietal attentional resources},

author = {Monika Intaitė and João Valente Duarte and Miguel Castelo-Branco},

doi = {10.1016/j.brainres.2016.08.044},

year  = {2016},

date = {2016-01-01},

journal = {Brain Research},

volume = {1650},

pages = {142–151},

abstract = {A visual stimulus is defined as ambiguous when observers perceive it as having at least two distinct and spontaneously alternating interpretations. Neuroimaging studies suggest an involvement of a right fronto-parietal network regulating the balance between stable percepts and the triggering of alternative interpretations. As spontaneous perceptual reversals may occur even in the absence of attention to these stimuli, we investigated neural activity patterns in response to perceptual changes of ambiguous Necker cube under different amounts of working memory load using a dual-task design. We hypothesized that the same regions that process working memory load are involved in perceptual switching and confirmed the prediction that perceptual reversals led to fMRI responses that linearly depended on load. Accordingly, posterior Superior Parietal Lobule, anterior Prefrontal and Dorsolateral Prefrontal cortices exhibited differential BOLD signal changes in response to perceptual reversals under working memory load. Our results also suggest that the posterior Superior Parietal Lobule may be directly involved in the emergence of perceptual reversals, given that it specifically reflects both perceptual versus real changes and load levels. The anterior Prefrontal and Dorsolateral Prefrontal cortices, showing a significant interaction between reversal levels and load, might subserve a modulatory role in such reversals, in a mirror symmetric way: in the former activation is suppressed by the highest loads, and in the latter deactivation is reduced by highest loads, suggesting a more direct role of the aPFC in reversal generation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jeong2016,

title = {The impact of top-down spatial attention on laterality and hemispheric asymmetry in the human parietal cortex},

author = {Su Keun Jeong and Yaoda Xu},

doi = {10.1167/16.10.2},

year  = {2016},

date = {2016-01-01},

journal = {Journal of Vision},

volume = {16},

number = {10},

pages = {1–21},

abstract = {The human parietal cortex exhibits a preference to contralaterally presented visual stimuli (i.e., laterality) as well as an asymmetry between the two hemispheres with the left parietal cortex showing greater laterality than the right. Using visual short-term memory and perceptual tasks and varying target location predictability, this study examined whether hemispheric laterality and asymmetry are fixed characteristics of the human parietal cortex or whether they are dynamic and modulated by the deployment of top-down attention to the target present hemifield. Two parietal regions were examined here that have previously been shown to be involved in visual object individuation and identification and are located in the inferior and superior intraparietal sulcus (IPS), respectively. Across three experiments, significant laterality was found in both parietal regions regardless of attentional modulation with laterality being greater in the inferior than superior IPS, consistent with their roles in object individuation and identification, respectively. Although the deployment of top-down attention had no effect on the superior IPS, it significantly increased laterality in the inferior IPS. The deployment of top-down spatial attention can thus amplify the strength of laterality in the inferior IPS. Hemispheric asymmetry, on the other hand, was absent in both brain regions and only emerged in the inferior but not the superior IPS with the deployment of top-down attention. Interestingly, the strength of hemispheric asymmetry significantly correlated with the strength of laterality in the inferior IPS. Hemispheric asymmetry thus seems to only emerge when there is a sufficient amount of laterality present in a brain region.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kasparbauer2016,

title = {Neural effects of methylphenidate and nicotine during smooth pursuit eye movements},

author = {Anna-Maria Kasparbauer and Inga Meyhöfer and Maria Steffens and Bernd Weber and Merve Aydin and Veena Kumari and Rene Hurlemann and Ulrich Ettinger},

doi = {10.1016/j.neuroimage.2016.07.012},

year  = {2016},

date = {2016-01-01},

journal = {NeuroImage},

volume = {141},

pages = {52–59},

publisher = {Elsevier Inc.},

abstract = {Introduction: Nicotine and methylphenidate are putative cognitive enhancers in healthy and patient populations. Although they stimulate different neurotransmitter systems, they have been shown to enhance performance on overlapping measures of attention. So far, there has been no direct comparison of the effects of these two stimulants on behavioural performance or brain function in healthy humans. Here, we directly compare the two compounds using a well-established oculomotor biomarker in order to explore common and distinct behavioural and neural effects. Methods: Eighty-two healthy male non-smokers performed a smooth pursuit eye movement task while lying in an fMRI scanner. In a between-subjects, double-blind design, subjects either received placebo (placebo patch and capsule), nicotine (7 mg nicotine patch and placebo capsule), or methylphenidate (placebo patch and 40 mg methylphenidate capsule). Results: There were no significant drug effects on behavioural measures. At the neural level, methylphenidate elicited higher activation in left frontal eye field compared to nicotine, with an intermediate response under placebo. Discussion: The reduced activation of task-related regions under nicotine could be associated with more efficient neural processing, while increased hemodynamic response under methylphenidate is interpretable as enhanced processing of task-relevant networks. Together, these findings suggest dissociable neural effects of these putative cognitive enhancers.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Knapen2016a,

title = {Oculomotor remapping of visual information to foveal retinotopic cortex},

author = {Tomas Knapen and Jascha D. Swisher and Frank Tong and Patrick Cavanagh},

doi = {10.3389/fnsys.2016.00054},

year  = {2016},

date = {2016-01-01},

journal = {Frontiers in Systems Neuroscience},

volume = {10},

pages = {54},

abstract = {Our eyes continually jump around the visual scene to bring the high-resolution, central part of our vision onto objects of interest. We are oblivious to these abrupt shifts, perceiving the visual world to appear reassuringly stable. A process called remapping has been proposed to mediate this perceptual stability for attended objects by shifting their retinotopic representation to compensate for the effects of the upcoming eye movement. In everyday vision, observers make goal-directed eye movements towards items of interest bringing them to the fovea and, for these items, the remapped activity should impinge on foveal regions of the retinotopic maps in visual cortex. Previous research has focused instead on remapping for targets that were not saccade goals, where activity is remapped to a new peripheral location rather than to the foveal representation. We used functional MRI and a phase-encoding design to investigate remapping of spatial patterns of activity towards the fovea/parafovea for saccade targets that were removed prior to completion of the eye movement. We found strong evidence of foveal remapping in retinotopic visual areas, which failed to occur when observers merely attended to the same peripheral target without making eye movements toward it. Significantly, the spatial profile of the remapped response matched the orientation and size of the saccade target, and was appropriately scaled to reflect the retinal extent of the stimulus had it been foveated. We conclude that this remapping of spatially structured information to the fovea may serve as an important mechanism to support our world-centered sense of location across goal-directed eye movements under natural viewing conditions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Roth2015,

title = {Position and identity information available in fMRI patterns of activity in human visual cortex},

author = {Zvi N. Roth and Ehud Zohary},

doi = {10.1523/JNEUROSCI.0752-15.2015},

year  = {2015},

date = {2015-08-01},

journal = {Journal of Neuroscience},

volume = {35},

number = {33},

pages = {11559–11571},

publisher = {Society for Neuroscience},

abstract = {Parietal cortex is often implicated in visual processing of actions. Action understanding is essentially abstract, specific to the type or goal of action, but greatly independent of variations in the perceived position of the action. If certain parietal regions are involved in action understanding, then we expect them to show these generalization and selectivity properties. However, additional functions of parietal cortex, such as self-action control, may impose other demands by requiring an accurate representation of the location of graspable objects. Therefore, the dimensions along which responses are modulated may indicate the functional role of specific parietal regions. Here, we studied the degree of position invariance and hand/object specificity during viewing of tool-grasping actions. To that end, we characterize the information available about location, hand, and tool identity in the patterns of fMRI activation in various cortical areas: early visual cortex, posterior intraparietal sulcus, anterior superior parietal lobule, and the ventral object-specific lateral occipital complex. Our results suggest a gradient within the human dorsal stream: along the posterior-anterior axis, position information is gradually lost, whereas hand and tool identity information is enhanced. This may reflect a gradual transformation of visual input from an initial retinotopic representation in early visual areas to an abstract, position-invariant representation of viewed action in anterior parietal cortex.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Saber2015,

title = {Saccade planning evokes topographically specific activity in the dorsal and ventral streams},

author = {Golbarg T. Saber and Franco Pestilli and Clayton E. Curtis},

doi = {10.1523/JNEUROSCI.1687-14.2015},

year  = {2015},

date = {2015-01-01},

journal = {Journal of Neuroscience},

volume = {35},

number = {1},

pages = {245–252},

abstract = {Saccade planning may invoke spatially-specific feedback signals that bias early visual activity in favor of top-down goals. We tested this hypothesis by measuring cortical activity at the early stages of the dorsal and ventral visual processing streams. Human subjects maintained saccade plans to (prosaccade) or away (antisaccade) from a spatial location over long memory-delays. Results show that cortical activity persists in early visual cortex at the retinotopic location of upcoming saccade goals. Topographically specific activity persists as early as V1, and activity increases along both dorsal (V3A/B, IPS0) and ventral (hV4, VO1) visual areas. Importantly, activity persists when saccade goals are available only via working memory and when visual targets and saccade goals are spatially disassociated. We conclude that top-down signals elicit retinotopically specific activity in visual cortex both in the dorsal and ventral streams. Such activity may underlie mechanisms that prioritize locations of task-relevant objects.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Schuster2015,

title = {Eyes on words: A fixation-related fMRI study of the left occipito-temporal cortex during self-paced silent reading of words and pseudowords},

author = {Sarah Schuster and Stefan Hawelka and Fabio Richlan and Philipp Ludersdorfer and Florian Hutzler},

doi = {10.1038/srep12686},

year  = {2015},

date = {2015-01-01},

journal = {Scientific Reports},

volume = {5},

pages = {12686},

publisher = {Nature Publishing Group},

abstract = {The predominant finding of studies assessing the response of the left ventral occipito-temporal cortex (vOT) to familiar words and to unfamiliar, but pronounceable letter strings (pseudowords) is higher activation for pseudowords. One explanation for this finding is that readers automatically generate predictions about a letter string's identity – pseudowords mismatch these predictions and the higher vOT activation is interpreted as reflecting the resultant prediction errors. The majority of studies, however, administered tasks which imposed demands above and beyond the intrinsic requirements of visual word recognition. The present study assessed the response of the left vOT to words and pseudowords by using the onset of the first fixation on a stimulus as time point for modeling the BOLD signal (fixation-related fMRI). This method allowed us to assess the neural correlates of self-paced silent reading with minimal task demands and natural exposure durations. In contrast to the predominantly reported higher vOT activation for pseudowords, we found higher activation for words. This finding is at odds with the expectation of higher vOT activation for pseudowords due to automatically generated predictions and the accompanying elevation of prediction errors. Our finding conforms to an alternative explanation which considers such top-down processing to be non-automatic and task-dependent.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tramper2015,

title = {Parallel updating and weighting of multiple spatial maps for visual stability during whole body motion},

author = {J. J. Tramper and W. Pieter Medendorp},

doi = {10.1152/jn.00576.2015},

year  = {2015},

date = {2015-01-01},

journal = {Journal of Neurophysiology},

volume = {114},

number = {6},

pages = {3211–3219},

abstract = {It is known that the brain uses multiple reference frames to code spatial information, including eye-centered and body-centered frames. When we move our body in space, these internal representations are no longer in register with external space, unless they are actively updated. Whether the brain updates multiple spatial representations in parallel, or whether it restricts its updating mechanisms to a single reference frame from which other representations are constructed, remains an open question. We developed an optimal integration model to simulate the updating of visual space across body motion in multiple or single reference frames. To test this model, we designed an experiment in which participants had to remember the location of a briefly presented target while being translated sideways. The behavioral responses were in agreement with a model that uses a combination of eye- and body-centered representations, weighted according to the reliability in which the target location is stored, and updated in each reference frame. Our findings suggest that the brain simultaneously updates multiple spatial representations across body motion. Because both representations are kept in sync, they can be optimally combined to provide a more precise estimate of visual locations in space than based on single-frame updating mechanisms.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{VanBergen2015,

title = {Sensory uncertainty decoded from visual cortex predicts behavior Ruben},

author = {Ruben S. Van Bergen and Wei Ji Ma and Michael S. Pratte and Janneke F. M. Jehee},

year  = {2015},

date = {2015-01-01},

journal = {Nature Neuroscience},

volume = {18},

number = {12},

pages = {1728–1730},

abstract = {Bayesian theories of neural coding propose that sensory uncertainty is represented by a probability distribution encoded in neural population activity, but direct neural evidence supporting this hypothesis is currently lacking. Using fMRI in combination with a generative model-based analysis, we found that probability distributions reflecting sensory uncertainty could reliably be estimated from human visual cortex and, moreover, that observers appeared to use knowledge of this uncertainty in their perceptual decisions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Visser2015,

title = {Representational similarity analysis offers a preview of the noradrenergic modulation of long-term fear memory at the time of encoding},

author = {Renée M. Visser and Anna E. Kunze and Bianca Westhoff and H. Steven Scholte and Merel Kindt},

doi = {10.1016/j.psyneuen.2015.01.021},

year  = {2015},

date = {2015-01-01},

journal = {Psychoneuroendocrinology},

volume = {55},

pages = {8–20},

publisher = {Elsevier Ltd},

abstract = {Neuroimaging research on emotional memory has greatly advanced our understanding of the pathogenesis of anxiety disorders. While the behavioral expression of fear at the time of encoding does not predict whether an aversive experience will evolve into long-term fear memory, the application of multi-voxel pattern analysis (MVPA) for the analysis of BOLD-MRI data has recently provided a unique marker for memory formation. Here, we aimed to further investigate the utility of this marker by modulating the strength of fear memory with an α2-adrenoceptor antagonist (yohimbine HCl). Fifty-two healthy participants were randomly assigned to two conditions - either receiving 20. mg yohimbine or a placebo pill (double-blind) - prior to differential fear conditioning and MRI-scanning. We examined the strength of fear associations during acquisition and retention of fear (48. h later) by assessing the similarity of BOLD-MRI patterns and pupil dilation responses. Additionally, participants returned for a follow-up test outside the scanner (2-4 weeks), during which we assessed fear-potentiated startle responses. Replicating our previous findings, neural pattern similarity reflected the development of fear associations over time, and unlike average activation or pupil dilation, predicted the later expression of fear memory (pupil dilation 48. h later). While no effect of yohimbine was observed on markers of autonomic arousal, including salivary α-amylase (sAA), we obtained indirect evidence for the noradrenergic enhancement of fear memory consolidation: sAA levels showed a strong increase prior to fMRI scanning, irrespective of whether participants had received yohimbine, and this increase correlated with the subsequent expression of fear (48. h later). Remarkably, this noradrenergic enhancement of fear was associated with changes in neural response patterns at the time of learning. These findings provide further evidence that representational similarity analysis is a sensitive tool for studying (enhanced) memory formation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Vossel2015,

title = {Cortical coupling reflects Bayesian belief updating in the deployment of spatial attention},

author = {Simone Vossel and Christoph Mathys and Klaas E. Stephan and Karl J. Friston},

doi = {10.1523/JNEUROSCI.1382-15.2015},

year  = {2015},

date = {2015-01-01},

journal = {Journal of Neuroscience},

volume = {35},

number = {33},

pages = {11532–11542},

abstract = {The deployment of visuospatial attention and the programming of saccades are governed by the inferred likelihood of events. In the present study, we combined computational modeling of psychophysical data with fMRI to characterize the computational and neural mechanisms underlying this flexible attentional control. Sixteen healthy human subjects performed a modified version of Posner's location-cueing paradigm in which the percentage of cue validity varied in time and the targets required saccadic responses. Trialwise estimates of the certainty (precision) of the prediction that the target would appear at the cued location were derived from a hierarchical Bayesian model fitted to individual trialwise saccadic response speeds. Trial-specific model parameters then entered analyses of fMRI data as parametric regressors. Moreover, dynamic causal modeling (DCM) was performed to identify the most likely functional architecture of the attentional reorienting network and its modulation by (Bayes-optimal) precision-dependent attention. While the frontal eye fields (FEFs), intraparietal sulcus, and temporoparietal junction (TPJ) of both hemispheres showed higher activity on invalid relative to valid trials, reorienting responses in right FEF, TPJ, and the putamen were significantly modulated by precision-dependent attention. Our DCM results suggested that the precision of predictability underlies the attentional modulation of the coupling of TPJ with FEF and the putamen. Our results shed new light on the computational architecture and neuronal network dynamics underlying the context-sensitive deployment of visuospatial attention.$backslash$n$backslash$nSIGNIFICANCE STATEMENT: Spatial attention and its neural correlates in the human brain have been studied extensively with the help of fMRI and cueing paradigms in which the location of targets is pre-cued on a trial-by-trial basis. One aspect that has so far been neglected concerns the question of how the brain forms attentional expectancies when no a priori probability information is available but needs to be inferred from observations. This study elucidates the computational and neural mechanisms under which probabilistic inference governs attentional deployment. Our results show that Bayesian belief updating explains changes in cortical connectivity; in that directional influences from the temporoparietal junction on the frontal eye fields and the putamen were modulated by (Bayes-optimal) updates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Griffis2015,

title = {Distinct effects of trial-driven and task set-related control in primary visual cortex},

author = {Joseph C. Griffis and Abdurahman S. Elkhetali and Ryan J. Vaden and Kristina M. Visscher},

doi = {10.1007/s10995-015-1800-4.Alcohol},

year  = {2015},

date = {2015-01-01},

journal = {NeuroImage},

volume = {120},

pages = {285–297},

abstract = {Task sets are task-specific configurations of cognitive processes that facilitate task-appropriate reactions to stimuli. While it is established that the trial-by-trial deployment of visual attention to expected stimuli influences neural responses in primary visual cortex (V1) in a retinotopically specific manner, it is not clear whether the mechanisms that help maintain a task set over many trials also operate with similar retinotopic specificity. Here, we address this question by using BOLD fMRI to characterize how portions of V1 that are specialized for different eccentricities respond during distinct components of an attention-demanding discrimination task: cue-driven preparation for a trial, trial-driven processing, task-initiation at the beginning of a block of trials, and task-maintenance throughout a block of trials. Tasks required either unimodal attention to an auditory or a visual stimulus or selective intermodal attention to the visual or auditory component of simultaneously presented visual and auditory stimuli. We found that while the retinotopic patterns of trial-driven and cue-driven activity depended on the attended stimulus, the retinotopic patterns of task-initiation and task-maintenance activity did not. Further, only the retinotopic patterns of trial-driven activity were found to depend on the presence of inter-modal distraction. Participants who performed well on the intermodal selective attention tasks showed strong task-specific modulations of both trial-driven and task-maintenance activity. Importantly, task-related modulations of trial-driven and task-maintenance activity were in opposite directions. Together, these results confirm that there are (at least) two different processes for top-down control of V1: One, working trial-by-trial, differently modulates activity across different eccentricity sectors - portions of V1 corresponding to different visual eccentricities. The second process works across longer epochs of task performance, and does not differ among eccentricity sectors. These results are discussed in the context of previous literature examining top-down control of visual cortical areas.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Grueschow2015,

title = {Automatic versus choice-dependent value representations in the human brain},

author = {Marcus Grueschow and Rafael Polania and Todd A. Hare and Christian C. Ruff},

doi = {10.1016/j.neuron.2014.12.054},

year  = {2015},

date = {2015-01-01},

journal = {Neuron},

volume = {85},

number = {4},

pages = {874–885},

publisher = {Elsevier Inc.},

abstract = {The subjective values of choice options can impact on behavior in two fundamentally different types of situations: first, when people explicitly base their actions on such values, and second, when values attract attention despite being irrelevant for current behavior. Here we show with functional magnetic resonance imaging (fMRI) that these two behavioral functions of values are encoded in distinct regions of the human brain. In the medial prefrontal cortex, value-related activity is enhanced when subjective value becomes choice-relevant, and the magnitude of this increase relates directly to the outcome and reliability of the value-based choice. In contrast, activity in the posterior cingulate cortex represents values similarly when they are relevant or irrelevant for the present choice, and the strength of this representation predicts attentional capture by choice-irrelevant values. Our results suggest that distinct components of the brain's valuation network encode value in context-dependent manners that serve fundamentally different behavioral aims.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Heikkinen2015,

title = {Feedback to distal dendrites links fMRI signals to neural receptive fields in a spiking network model of the visual cortex},

author = {Hanna Heikkinen and Fariba Sharifian and Ricardo Vigario and Simo Vanni},

doi = {10.1152/jn.00169.2015},

year  = {2015},

date = {2015-01-01},

journal = {Journal of Neurophysiology},

volume = {114},

number = {1},

pages = {57–69},

abstract = {The blood oxygenation level-dependent (BOLD) response has been strongly associated with neuronal activity in the brain. However, some neuronal tuning properties are consistently different from the BOLD response. We studied the spatial extent of neural and hemodynamic responses in the primary visual cortex, where the BOLD responses spread and interact over much longer distances than the small receptive fields of individual neurons would predict. Our model shows that a feedforward-feedback loop between V1 and a higher visual area can account for the observed spread of the BOLD response. In particular, anisotropic landing of inputs to compartmental neurons were necessary to account for the BOLD signal spread, while retaining realistic spiking responses. Our work shows that simple dendrites can separate tuning at the synapses and at the action potential output, thus bridging the BOLD signal to the neural receptive fields with high fidelity.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Henderson2015,

title = {Neural correlates of fixation duration during real-world scene viewing: Evidence from fixation-related (FIRE) fMRI},

author = {John M. Henderson and Wonil Choi},

year  = {2015},

date = {2015-01-01},

journal = {Journal of Cognitive Neuroscience},

volume = {27},

number = {6},

pages = {1137–1145},

abstract = {During active scene perception, our eyes move from one location to another via saccadic eye movements, with the eyes fixating objects and scene elements for varying amounts of time. Much of the variability in fixation duration is accounted for by attentional, perceptual, and cognitive processes associated with scene analysis and comprehension. For this reason, current theories of active scene viewing attempt to account for the influence of attention and cognition on fixation duration. Yet almost nothing is known about the neurocognitive systems associated with variation in fixation duration during scene viewing. We addressed this topic using fixation-related fMRI, which involves coregistering high-resolution eye tracking and magnetic resonance scanning to conduct event-related fMRI analysis based on characteristics of eye movements. We observed that activation in visual and prefrontal executive control areas was positively correlated with fixation duration, whereas activation in ventral areas associated with scene en- coding and medial superior frontal and paracentral regions associated with changing action plans was negatively correlated with fixation duration. The results suggest that fixation duration in scene viewing is controlled by cognitive processes associated with real-time scene analysis interacting with motor planning, consistent with current computational models of active vision for scene perception.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Henderson2015a,

title = {Neural correlates of fixation duration in natural reading: Evidence from fixation-related fMRI},

author = {John M. Henderson and Wonil Choi and Steven G. Luke and Rutvik H. Desai},

doi = {10.1016/j.neuroimage.2015.06.072},

year  = {2015},

date = {2015-01-01},

journal = {NeuroImage},

volume = {119},

pages = {390–397},

publisher = {Elsevier Inc.},

abstract = {A key assumption of current theories of natural reading is that fixation duration reflects underlying attentional, language, and cognitive processes associated with text comprehension. The neurocognitive correlates of this relationship are currently unknown. To investigate this relationship, we compared neural activation associated with fixation duration in passage reading and a pseudo-reading control condition. The results showed that fixation duration was associated with activation in oculomotor and language areas during text reading. Fixation duration during pseudo-reading, on the other hand, showed greater involvement of frontal control regions, suggesting flexibility and task dependency of the eye movement network. Consistent with current models, these results provide support for the hypothesis that fixation duration in reading reflects attentional engagement and language processing. The results also demonstrate that fixation-related fMRI provides a method for investigating the neurocognitive bases of natural reading.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jamadar2015,

title = {Behavioral and neural plasticity of ocular motor control: Changes in performance and fMRI activity following antisaccade training},

author = {Sharna D. Jamadar and Beth P. Johnson and Meaghan Clough and Gary F. Egan and Joanne Fielding},

doi = {10.3389/fnhum.2015.00653},

year  = {2015},

date = {2015-01-01},

journal = {Frontiers in Human Neuroscience},

volume = {9},

number = {653},

pages = {1–13},

abstract = {The antisaccade task provides a model paradigm that sets the inhibition of a reflexively driven behavior against the volitional control of a goal-directed behavior. The stability and adaptability of antisaccade performance was investigated in 23 neurologically healthy individuals. Behavior and brain function were measured using functional magnetic resonance imaging (fMRI) prior to and immediately following 2 weeks of daily antisaccade training. Participants performed antisaccade trials faster with no change in directional error rate following 2 weeks of training; however this increased speed came at the cost of the spatial accuracy of the saccade (gain) which became more hypometric following training. Training on the antisaccade task resulted in increases in fMRI activity in the fronto-basal ganglia-parietal-cerebellar ocular motor network. Following training, antisaccade latency was positively associated with fMRI activity in the frontal and supplementary eye fields, anterior cingulate and intraparietal sulcus; antisaccade gain was negatively associated with fMRI activity in supplementary eye fields, anterior cingulate, intraparietal sulcus, and cerebellar vermis. In sum, the results suggest that following training, larger antisaccade latency is associated with larger activity in fronto-parietal-cerebellar ocular motor regions, and smaller antisaccade gain is associated with larger activity in fronto-parietal ocular motor regions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Meyhoefer2015,

title = {Neural mechanisms of smooth pursuit eye movements in schizotypy},

author = {Inga Meyhöfer and Maria Steffens and Anna-Maria Kasparbauer and Phillip Grant and Bernd Weber and Ulrich Ettinger},

doi = {10.1002/hbm.22632},

year  = {2015},

date = {2015-01-01},

journal = {Human Brain Mapping},

volume = {36},

pages = {340–353},

abstract = {Patients with schizophrenia as well as individuals with high levels of schizotypy are known to have deficits in smooth pursuit eye movements (SPEM). Here, we investigated, for the first time, the neural mechanisms underlying SPEM performance in high schizotypy. Thirty-one healthy participants [N = 19 low schizotypes},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Michael2015,

title = {Unreliable evidence: 2 sources of uncertainty during perceptual choice},

author = {Elizabeth Michael and Vincent De Gardelle and Alejo Nevado-Holgado and Christopher Summerfield},

doi = {10.1093/cercor/bht287},

year  = {2015},

date = {2015-01-01},

journal = {Cerebral Cortex},

volume = {25},

number = {4},

pages = {937–947},

abstract = {Perceptual decisions often involve integrating evidence from multiple concurrently available sources. Uncertainty arises when the integrated (mean) evidence fails to support one alternative over another. However, evidence heterogeneity (variability) also provokes uncertainty. Here, we asked whether these 2 sources of uncertainty have independent behavioral and neural effects during choice. Human observers undergoing functional neuroimaging judged the average color or shape of a multielement array. The mean and variance of the feature values exerted independent influences on behavior and brain activity. Surprisingly, BOLD signals in the dorsomedial prefrontal cortex (dmPFC) showed polar opposite responses to the 2 sources of uncertainty, with the strongest response to ambiguous tallies of evidence (high mean uncertainty) and to homogenous arrays (low variance uncertainty). These findings present a challenge for models that emphasize the role of the dmPFC in detecting conflict, errors, or surprise. We suggest an alternative explanation, whereby evidence is processed with increased gain near the category boundary.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{MuellerPinzler2015,

title = {Neural pathways of embarrassment and their modulation by social anxiety},

author = {L. Müller-Pinzler and V. Gazzola and C. Keysers and Jens Sommer and Andreas Jansen and S. Frässle and Wolfgang Einhäuser and Frieder M. Paulus and Sören Krach},

doi = {10.1016/j.neuroimage.2015.06.036},

year  = {2015},

date = {2015-01-01},

journal = {NeuroImage},

volume = {119},

pages = {252–261},

publisher = {Elsevier Inc.},

abstract = {While being in the center of attention and exposed to other's evaluations humans are prone to experience embarrassment. To characterize the neural underpinnings of such aversive moments, we induced genuine experiences of embarrassment during person-group interactions in a functional neuroimaging study. Using a mock-up scenario with three confederates, we examined how the presence of an audience affected physiological and neural responses and the reported emotional experiences of failures and achievements. The results indicated that publicity induced activations in mentalizing areas and failures led to activations in arousal processing systems. Mentalizing activity as well as attention towards the audience were increased in socially anxious participants. The converging integration of information from mentalizing areas and arousal processing systems within the ventral anterior insula and amygdala forms the neural pathways of embarrassment. Targeting these neural markers of embarrassment in the (para-)limbic system provides new perspectives for developing treatment strategies for social anxiety disorders.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Paulus2015,

title = {Fronto-insula network activity explains emotional dysfunctions in juvenile myoclonic epilepsy: Combined evidence from pupillometry and fMRI},

author = {Frieder M. Paulus and Sören Krach and Marius Blanke and Christine Roth and Marcus Belke and Jens Sommer and Laura Müller-Pinzler and Katja Menzler and Andreas Jansen and Felix Rosenow and Frank Bremmer and Wolfgang Einhäuser and Susanne Knake},

doi = {10.1044/2018_AJSLP-17-0074},

year  = {2015},

date = {2015-01-01},

journal = {Cortex},

volume = {65},

pages = {219–231},

abstract = {Emotional instability, difficulties in social adjustment, and disinhibited behavior are the most common symptoms of the psychiatric comorbidities in juvenile myoclonic epilepsy (JME). This psychopathology has been associated with dysfunctions of mesial-frontal brain circuits. The present work is a first direct test of this link and adapted a paradigm for probing frontal circuits during empathy for pain. Neural and psychophysiological parameters of pain empathy were assessed by combining functional magnetic resonance imaging (fMRI) with simultaneous pupillometry in 15 JME patients and 15 matched healthy controls. In JME patients, we observed reduced neural activation of the anterior cingulate cortex (ACC), the anterior insula (AI), and the ventrolateral prefrontal cortex (VLPFC). This modulation was paralleled by reduced pupil dilation during empathy for pain in patients. At the same time, pupil dilation was positively related to neural activity of the ACC, AI, and VLPFC. In JME patients, the ACC additionally showed reduced functional connectivity with the primary and secondary somatosensory cortex, areas fundamentally implicated in processing the somatic cause of another's pain. Our results provide first evidence that alterations of mesial-frontal circuits directly affect psychosocial functioning in JME patients and draw a link of pupil dynamics with brain activity during emotional processing. The findings of reduced pain empathy related activation of the ACC and AI and aberrant functional integration of the ACC with somatosensory cortex areas provide further evidence for this network's role in social behavior and helps explaining the JME psychopathology and patients' difficulties in social adjustment.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Peters2015,

title = {Activity in human visual and parietal cortex reveals object-based attention in working memory},

author = {Benjamin Peters and Jochen Kaiser and Benjamin Rahm and Christoph Bledowski},

doi = {10.1523/JNEUROSCI.3795-14.2015},

year  = {2015},

date = {2015-01-01},

journal = {Journal of Neuroscience},

volume = {35},

number = {8},

pages = {3360–3369},

abstract = {Visual attention enables observers to select behaviorally relevant information based on spatial locations, features, or objects. Attentional selection is not limited to physically present visual information, but can also operate on internal representations maintained in working memory (WM) in service of higher-order cognition. However, only little is known about whether attention to WM contents follows the same principles as attention to sensory stimuli. To address this question, we investigated in humans whether the typically observed effects of object-based attention in perception are also evident for object-based attentional selection of internal object representations in WM. In full accordance with effects in visual perception, the key behavioral and neuronal characteristics of object-based attention were observed in WM. Specifically, we found that reaction times were shorter when shifting attention to memory positions located on the currently attended object compared with equidistant positions on a different object. Furthermore, functional magnetic resonance imaging and multivariate pattern analysis of visuotopic activity in visual (areas V1-V4) and parietal cortex revealed that directing attention to one position of an object held in WM also enhanced brain activation for other positions on the same object, suggesting that attentional selection in WM activates the entire object. This study demonstrated that all characteristic features of object-based attention are present in WM and thus follows the same principles as in perception.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Myers2015,

title = {Testing sensory evidence against mnemonic templates},

author = {Nicholas E. Myers and Gustavo Rohenkohl and Valentin Wyart and Mark W. Woolrich and Anna C. Nobre and Mark G. Stokes},

doi = {10.7554/eLife.09000.001},

year  = {2015},

date = {2015-01-01},

journal = {eLife},

volume = {4},

pages = {1–25},

abstract = {Most perceptual decisions require comparisons between current input and an internal template. Classic studies propose that templates are encoded in sustained activity of sensory neurons. However, stimulus encoding is itself dynamic, tracing a complex trajectory through activity space. Which part of this trajectory is pre-activated to reflect the template? Here we recorded magneto- and electroencephalography during a visual target-detection task, and used pattern analyses to decode template, stimulus, and decision-variable representation. Our findings ran counter to the dominant model of sustained pre-activation. Instead, template information emerged transiently around stimulus onset and quickly subsided. Cross-generalization between stimulus and template coding, indicating a shared neural representation, occurred only briefly. Our results are compatible with the proposal that template representation relies on a matched filter, transforming input into task-appropriate output. This proposal was consistent with a signed difference response at the perceptual decision stage, which can be explained by a simple neural model.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wallis2015a,

title = {Frontoparietal and cingulo-opercular networks play dissociable roles in control of working memory},

author = {George Wallis and Mark Stokes and Helena Cousijn and Mark W. Woolrich and Anna C. Nobre},

year  = {2015},

date = {2015-01-01},

journal = {Journal of Cognitive Neuroscience},

volume = {27},

pages = {2019–2034},

abstract = {We used magnetoencephalography to characterize the spatiotemporal dynamics of cortical activity during top–down control of working memory (WM). fMRI studies have previously implicated both the frontoparietal and cingulo-opercular networks in control over WM, but their respective contributions are unclear. In our task, spatial cues indicating the relevant item in a WM array occurred either before the memory array or during the maintenance period, providing a direct comparison between prospective and retrospective control of WM. We found that in both cases a frontoparietal network activated following the cue, but following retrocues this activation was transient and was succeeded by a cinguloopercular network activation. We also characterized the time course of top–down modulation of alpha activity in visual/parietal cortex. This modulation was transient following retrocues, occurring in parallel with the frontoparietal network activation. We suggest that the frontoparietal network is responsible for top–down modulation of activity in sensory cortex during both preparatory attention and orienting within memory. In contrast, the cinguloopercular network plays a more downstream role in cognitive control, perhaps associated with output gating of memory},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Okazaki2015,

title = {Real-time MEG neurofeedback training of posterior alpha activity modulates subsequent visual detection performance},

author = {Yuka O. Okazaki and Jörn M. Horschig and Lisa Luther and Robert Oostenveld and Ikuya Murakami and Ole Jensen},

doi = {10.1016/j.neuroimage.2014.12.014},

year  = {2015},

date = {2015-01-01},

journal = {NeuroImage},

volume = {107},

pages = {323–332},

publisher = {Elsevier Inc.},

abstract = {It has been demonstrated that alpha activity is lateralized when attention is directed to the left or right visual hemifield. We investigated whether real-time neurofeedback training of the alpha lateralization enhances participants' ability to modulate posterior alpha lateralization and causes subsequent short-term changes in visual detection performance. The experiment consisted of three phases: (i) pre-training assessment, (ii) neurofeedback phase and (iii) post-training assessment. In the pre- and post-training phases we measured the threshold to covertly detect a cued faint Gabor stimulus presented in the left or right hemifield. During magnetoencephalography (MEG) neurofeedback, two face stimuli superimposed with noise were presented bilaterally. Participants were cued to attend to one of the hemifields. The transparency of the superimposed noise and thus the visibility of the stimuli were varied according to the momentary degree of hemispheric alpha lateralization. In a double-blind procedure half of the participants were provided with sham feedback. We found that hemispheric alpha lateralization increased with the neurofeedback training; this was mainly driven by an ipsilateral alpha increase. Surprisingly, comparing pre- to post-training, detection performance decreased for a Gabor stimulus presented in the hemifield that was un-attended during neurofeedback. This effect was not observed in the sham group. Thus, neurofeedback training alters alpha lateralization, which in turn decreases performances in the untrained hemifield. Our findings suggest that alpha oscillations play a causal role for the allocation of attention. Furthermore, our neurofeedback protocol serves to reduce the detection of unattended visual information and could therefore be of potential use for training to reduce distractibility in attention deficit patients, but also highlights that neurofeedback paradigms can have negative impact on behavioral performance and should be applied with caution.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wassenhove2015,

title = {Visual-induced expectations modulate auditory cortical responses},

author = {Virginie Wassenhove and Lukasz Grzeczkowski},

doi = {10.3389/fnins.2015.00011},

year  = {2015},

date = {2015-01-01},

journal = {Frontiers in Neuroscience},

volume = {9},

pages = {11},

abstract = {Active sensing has important consequences on multisensory processing (Schroeder et al., 2010). Here, we asked whether in the absence of saccades, the position of the eyes and the timing of transient color changes of visual stimuli could selectively affect the excitability of auditory cortex by predicting the "where" and the "when" of a sound, respectively. Human participants were recorded with magnetoencephalography (MEG) while maintaining the position of their eyes on the left, right, or center of the screen. Participants counted color changes of the fixation cross while neglecting sounds which could be presented to the left, right, or both ears. First, clear alpha power increases were observed in auditory cortices, consistent with participants' attention directed to visual inputs. Second, color changes elicited robust modulations of auditory cortex responses ("when" prediction) seen as ramping activity, early alpha phase-locked responses, and enhanced high-gamma band responses in the contralateral side of sound presentation. Third, no modulations of auditory evoked or oscillatory activity were found to be specific to eye position. Altogether, our results suggest that visual transience can automatically elicit a prediction of "when" a sound will occur by changing the excitability of auditory cortices irrespective of the attended modality, eye position or spatial congruency of auditory and visual events. To the contrary, auditory cortical responses were not significantly affected by eye position suggesting that "where" predictions may require active sensing or saccadic reset to modulate auditory cortex responses, notably in the absence of spatial orientation to sounds.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tan2015,

title = {MEG-measured auditory steady-state oscillations show high test-retest reliability: A sensor and source-space analysis},

author = {Heng Ru May Tan and Joachim Gross and P. J. Uhlhaas},

doi = {10.1016/j.neuroimage.2015.07.055},

year  = {2015},

date = {2015-01-01},

journal = {NeuroImage},

volume = {122},

pages = {417–426},

publisher = {The Authors},

abstract = {Stability of oscillatory signatures across magnetoencephalography (MEG) measurements is an important prerequisite for basic and clinical research that has been insufficiently addressed. Here, we evaluated the test-retest reliability of auditory steady-state responses (ASSRs) over two MEG sessions. The study required participants (N. = 13) to detect the rare occurrence of pure tones interspersed within a stream of 5. Hz or 40. Hz amplitude-modulated (AM) tones. Intraclass correlations (ICC; Shrout and Fleiss, 1979) were derived to assess stability of spectral power changes and the inter-trial phase coherence (ITPC) of task-elicited neural responses. ASSRs source activity was estimated using eLORETA beamforming from bilateral auditory cortex. ASSRs to 40. Hz AM stimuli evoked stronger power modulation and phase-locking than 5. Hz stimulation. Overall, spectral power and ITPC values at both sensor- and source-level showed robust ICC values. Notably, ITPC measures yielded higher ICCs (~. 0.86-0.96) between sessions compared to the assessment of spectral power change (~. 0.61-0.82). Our data indicate that spectral modulations and phase consistency of ASSRs in MEG data are highly reproducible, providing support for MEG-measured oscillatory parameters in basic and clinical research.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Yellin2015,

title = {Coupling between pupil fluctuations and resting-state fMRI uncovers a slow build-up of antagonistic responses in the human cortex},

author = {Dov Yellin and Aviva Berkovich-Ohana and Rafael Malach},

doi = {10.1016/j.neuroimage.2014.11.034},

year  = {2015},

date = {2015-01-01},

journal = {NeuroImage},

volume = {106},

pages = {414–427},

publisher = {Elsevier Inc.},

abstract = {Even in absence of overt tasks, the human cortex manifests rich patterns of spontaneous "resting state" BOLD-fMRI fluctuations. However, the link of these spontaneous fluctuations to behavior is presently unclear. Attempts to directly investigate this link invariably lead to disruptions of the resting state. Here we took advantage of the well-established association between pupil diameter and attentional gain to address this issue by examining the correlation between the resting state BOLD and pupil fluctuations. Our results uncover a spontaneously emerging spatiotemporal pupil-BOLD correlation whereby a slow buildup of activity in default mode areas preceded both pupil dilation and wide-spread BOLD suppression in sensorimotor cortex. Control experiments excluded a role for luminance fluctuations or fixation. Comparing the pupil-correlated patterns to activation maps during visual imagery revealed a substantial overlap. Our results indicate a link between behavior, as indexed by pupil diameter, and resting state BOLD fluctuations. These pupil dilations, assumed to be related to attentional gain, were associated with spontaneously emerging antagonism between fundamental cortical networks.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Auksztulewicz2015,

title = {Attentional enhancement of auditory mismatch responses: A DCM/MEG study},

author = {Ryszard Auksztulewicz and Karl J. Friston},

doi = {10.1093/cercor/bhu323},

year  = {2015},

date = {2015-01-01},

journal = {Cerebral Cortex},

volume = {25},

number = {11},

pages = {4273–4283},

abstract = {Despite similar behavioral effects, attention and expectation influence evoked responses differently: Attention typically enhances event-related responses, whereas expectation reduces them. This dissociation has been reconciled under predictive coding, where prediction errors are weighted by precision associated with attentional modulation. Here, we tested the predictive coding account of attention and expectation using magnetoencephalography and modeling. Temporal attention and sensory expectation were orthogonally manipulated in an auditory mismatch paradigm, revealing opposing effects on evoked response amplitude. Mismatch negativity (MMN) was enhanced by attention, speaking against its supposedly pre-attentive nature. This interaction effect was modeled in a canonical microcircuit using dynamic causal modeling, comparing models with modulation of extrinsic and intrinsic connectivity at different levels of the auditory hierarchy. While MMN was explained by recursive interplay of sensory predictions and prediction errors, attention was linked to the gain of inhibitory interneurons, consistent with its modulation of sensory precision.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bach2015,

title = {Sustained magnetic responses in temporal cortex reflect instantaneous significance of approaching and receding sounds},

author = {Dominik R. Bach and Nicholas Furl and Gareth Barnes and Raymond J. Dolan},

doi = {10.1371/journal.pone.0134060},

year  = {2015},

date = {2015-01-01},

journal = {PLoS ONE},

volume = {10},

number = {7},

pages = {e0134060},

abstract = {Rising sound intensity often signals an approaching sound source and can serve as a powerful warning cue, eliciting phasic attention, perception biases and emotional responses. How the evaluation of approaching sounds unfolds over time remains elusive. Here, we capitalised on the temporal resolution of magnetoencephalograpy (MEG) to investigate in humans a dynamic encoding of perceiving approaching and receding sounds. We compared magnetic responses to intensity envelopes of complex sounds to those of white noise sounds, in which intensity change is not perceived as approaching. Sustained magnetic fields over temporal sensors tracked intensity change in complex sounds in an approximately linear fashion, an effect not seen for intensity change in white noise sounds, or for overall intensity. Hence, these fields are likely to track approach/recession, but not the apparent (instantaneous) distance of the sound source, or its intensity as such. As a likely source of this activity, the bilateral inferior temporal gyrus and right temporo-parietal junction emerged. Our results indicate that discrete temporal cortical areas parametrically encode behavioural significance in moving sound sources where the signal unfolded in a manner reminiscent of evidence accumulation. This may help an understanding of how acoustic percepts are evaluated as behaviourally relevant, where our results highlight a crucial role of cortical areas.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Diwakar2015,

title = {Filling in the gaps: Anticipatory control of eye movements in chronic mild traumatic brain injury},

author = {Mithun Diwakar and Deborah L. Harrington and Jun Maruta and Jamshid Ghajar and Fady El-Gabalawy and Laura Muzzatti and Maurizio Corbetta and Ming-Xiong X. Huang and Roland R. Lee},

doi = {10.1016/j.nicl.2015.04.011},

year  = {2015},

date = {2015-01-01},

journal = {NeuroImage: Clinical},

volume = {8},

pages = {210–223},

publisher = {Elsevier B.V.},

abstract = {A barrier in the diagnosis of mild traumatic brain injury (mTBI) stems from the lack of measures that are adequately sensitive in detecting mild head injuries. MRI and CT are typically negative in mTBI patients with persistent symptoms of post-concussive syndrome (PCS), and characteristic difficulties in sustaining attention often go undetected on neuropsychological testing, which can be insensitive to momentary lapses in concentration. Conversely, visual tracking strongly depends on sustained attention over time and is impaired in chronic mTBI patients, especially when tracking an occluded target. This finding suggests deficient internal anticipatory control in mTBI, the neural underpinnings of which are poorly understood. The present study investigated the neuronal bases for deficient anticipatory control during visual tracking in 25 chronic mTBI patients with persistent PCS symptoms and 25 healthy control subjects. The task was performed while undergoing magnetoencephalography (MEG), which allowed us to examine whether neural dysfunction associated with anticipatory control deficits was due to altered alpha, beta, and/or gamma activity. Neuropsychological examinations characterized cognition in both groups. During MEG recordings, subjects tracked a predictably moving target that was either continuously visible or randomly occluded (gap condition). MEG source-imaging analyses tested for group differences in alpha, beta, and gamma frequency bands. The results showed executive functioning, information processing speed, and verbal memory deficits in the mTBI group. Visual tracking was impaired in the mTBI group only in the gap condition. Patients showed greater error than controls before and during target occlusion, and were slower to resynchronize with the target when it reappeared. Impaired tracking concurred with abnormal beta activity, which was suppressed in the parietal cortex, especially the right hemisphere, and enhanced in left caudate and frontaloral areas. Regional beta-amplitude demonstrated high classification accuracy (92%) compared to eye-tracking (65%) and neuropsychological variables (80%). These findings show that deficient internal anticipatory control in mTBI is associated with altered beta activity, which is remarkably sensitive given the heterogeneity of injuries.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{He2015a,

title = {Face processing in the brains of pre-school aged children measured with MEG},

author = {Wei He and Jon Brock and Blake W. Johnson},

doi = {10.1016/j.neuroimage.2014.11.029},

year  = {2015},

date = {2015-01-01},

journal = {NeuroImage},

volume = {106},

pages = {317–327},

publisher = {Elsevier Inc.},

abstract = {There are two competing theories concerning the development of face perception: a late maturation account and an early maturation account. Magnetoencephalography (MEG) neuroimaging holds promise for adjudicating between the two opposing accounts by providing objective neurophysiological measures of face processing, with sufficient temporal resolution to isolate face-specific brain responses from those associated with other sensory, cognitive and motor processes. The current study used a customized child MEG system to measure M100 and M170 brain responses in 15 children aged three to six years while they viewed faces, cars and their phase-scrambled counterparts. Compared to adults tested using the same stimuli in a conventional MEG system, children showed significantly larger and later M100 responses. Children's M170 responses, derived by subtracting the responses to phase-scrambled images from the corresponding images (faces or cars) were delayed in latency but otherwise resembled the adult M170. This component has not been obtained in previous studies of young children tested using conventional adult MEG systems. However children did show a markedly reduced M170 response to cars in comparison to adults. This may reflect children's lack of expertise with cars relative to faces. Taken together, these data are in accord with recent behavioural and neuroimaging data that support early maturation of the basic face processing functions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{He2015b,

title = {Development of effective connectivity in the core network for face perception},

author = {Wei He and Marta I. Garrido and Paul F. Sowman and Jon Brock and Blake W. Johnson},

doi = {10.1002/hbm.22762},

year  = {2015},

date = {2015-01-01},

journal = {Human Brain Mapping},

volume = {36},

number = {6},

pages = {2161–2173},

abstract = {This study measured effective connectivity within the core face network in young children using a paediatric magnetoencephalograph (MEG). Dynamic casual modeling (DCM) of brain responses was performed in a group of adults (N = 14) and a group of young children aged from 3 to 6 years (N = 15). Three candidate DCM models were tested, and the fits of the MEG data to the three models were compared at both individual and group levels. The results show that the connectivity structure of the core face network differs significantly between adults and children. Further, the relative strengths of face network connections were differentially modulated by experimental conditions in the two groups. These results support the interpretation that the core face network undergoes significant structural configuration and functional specialization between four years of age and adulthood.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Horschig2015,

title = {Modulation of posterior alpha activity by spatial attention allows for controlling a continuous brain–computer interface},

author = {Jörn M. Horschig and Wouter Oosterheert and Robert Oostenveld and Ole Jensen},

doi = {10.1007/s10548-014-0401-7},

year  = {2015},

date = {2015-01-01},

journal = {Brain Topography},

volume = {28},

number = {6},

pages = {852–864},

abstract = {Here we report that the modulation of alpha activity by covert attention can be used as a control signal in an online brain-computer interface, that it is reliable, and that it is robust. Subjects were instructed to orient covert visual attention to the left or right hemifield. We decoded the direction of attention from the magnetoencephalogram by a template matching classifier and provided the classification outcome to the subject in real-time using a novel graphical user interface. Training data for the templates were obtained from a Posner-cueing task conducted just before the BCI task. Eleven subjects participated in four sessions each. Eight of the subjects achieved classification rates significantly above chance level. Subjects were able to significantly increase their performance from the first to the second session. Individual patterns of posterior alpha power remained stable throughout the four sessions and did not change with increased performance. We conclude that posterior alpha power can successfully be used as a control signal in brain-computer interfaces. We also discuss several ideas for further improving the setup and propose future research based on solid hypotheses about behavioral consequences of modulating neuronal oscillations by brain computer interfacing.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kauppi2015,

title = {Towards brain-activity-controlled information retrieval: Decoding image relevance from MEG signals},

author = {Jukka Pekka Kauppi and Melih Kandemir and Veli Matti Saarinen and Lotta Hirvenkari and Lauri Parkkonen and Arto Klami and Riitta Hari and Samuel Kaski},

doi = {10.1016/j.neuroimage.2014.12.079},

year  = {2015},

date = {2015-01-01},

journal = {NeuroImage},

volume = {112},

pages = {288–298},

publisher = {Elsevier Inc.},

abstract = {We hypothesize that brain activity can be used to control future information retrieval systems. To this end, we conducted a feasibility study on predicting the relevance of visual objects from brain activity. We analyze both magnetoencephalographic (MEG) and gaze signals from nine subjects who were viewing image collages, a subset of which was relevant to a predetermined task. We report three findings: i) the relevance of an image a subject looks at can be decoded from MEG signals with performance significantly better than chance, ii) fusion of gaze-based and MEG-based classifiers significantly improves the prediction performance compared to using either signal alone, and iii) non-linear classification of the MEG signals using Gaussian process classifiers outperforms linear classification. These findings break new ground for building brain-activity-based interactive image retrieval systems, as well as for systems utilizing feedback both from brain activity and eye movements.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kloosterman2015,

title = {Top-down modulation in human visual cortex predicts the stability of a perceptual illusion},

author = {Niels A. Kloosterman and Thomas Meindertsma and Arjan Hillebrand and Bob W. Dijk and Victor A. F. Lamme and Tobias H. Donner},

doi = {10.1152/jn.00338.2014},

year  = {2015},

date = {2015-01-01},

journal = {Journal of Neurophysiology},

volume = {113},

number = {4},

pages = {1063–1076},

abstract = {Conscious perception sometimes fluctuates strongly, even when the sensory input is constant. For example, in motion-induced blindness (MIB), a salient visual target surrounded by a moving pattern suddenly disappears from perception, only to reappear after some variable time. Whereas such changes of perception result from fluctuations of neural activity, mounting evidence suggests that the perceptual changes, in turn, may also cause modulations of activity in several brain areas, including visual cortex. In this study, we asked whether these latter modulations might affect the subsequent dynamics of perception. We used magnetoencephalography (MEG) to measure modulations in cortical population activity during MIB. We observed a transient, retinotopically widespread modulation of beta (12-30 Hz)-frequency power over visual cortex that was closely linked to the time of subjects' behavioral report of the target disappearance. This beta modulation was a top-down signal, decoupled from both the physical stimulus properties and the motor response but contingent on the behavioral relevance of the perceptual change. Critically, the modulation amplitude predicted the duration of the subsequent target disappearance. We propose that the transformation of the perceptual change into a report triggers a top-down mechanism that stabilizes the newly selected perceptual interpretation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Leiken2015,

title = {Filling predictable and unpredictable gaps, with and without similarity-based interference: Evidence for LIFG effects of dependency processing},

author = {Kimberly Leiken and Brian McElree and Liina Pylkkänen},

doi = {10.3389/fpsyg.2015.01739},

year  = {2015},

date = {2015-01-01},

journal = {Frontiers in Psychology},

volume = {6},

pages = {1739},

abstract = {One of the most replicated findings in neurolinguistic literature on syntax is the increase of hemodynamic activity in the left inferior frontal gyrus (LIFG) in response to object relative (OR) clauses compared to subject relative clauses. However, behavioral studies have shown that ORs are primarily only costly when similarity-based interference is involved and recently, Leiken and Pylkkänen (2014) showed with magnetoencephalography (MEG) that an LIFG increase at an OR gap is also dependent on such interference. However, since ORs always involve a cue indicating an upcoming dependency formation, OR dependencies could be processed already prior to the gap-site and thus show no sheer dependency effects at the gap itself. To investigate the role of gap predictability in LIFG dependency effects, this MEG study compared ORs to verb phrase ellipsis (VPE), which was used as an example of a non-predictable dependency. Additionally, we explored LIFG sensitivity to filler-gap order by including right node raising structures, in which the order of filler and gap is reverse to that of ORs and VPE. Half of the stimuli invoked similarity-based interference and half did not. Our results demonstrate that LIFG effects of dependency can be elicited regardless of whether the dependency is predictable, the stimulus materials evoke similarity-based interference, or the filler precedes the gap. Thus, contrary to our own prior data, the current findings suggest a highly general role for the LIFG in dependency interpretation that is not limited to environments involving similarity-based interference. Additionally, the millisecond time-resolution of MEG allowed for a detailed characterization of the temporal profiles of LIFG dependency effects across our three constructions, revealing that the timing of these effects is somewhat construction-specific.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mandel2015,

title = {Brain responds to another person's eye blinks in a natural setting-the more empathetic the viewer the stronger the responses},

author = {Anne Mandel and Siiri Helokunnas and Elina Pihko and Riitta Hari},

doi = {10.1111/ejn.13011},

year  = {2015},

date = {2015-01-01},

journal = {European Journal of Neuroscience},

volume = {42},

number = {8},

pages = {2508–2514},

abstract = {An observer's brain is known to respond to another person's small nonverbal signals, such as gaze shifts and eye blinks. Here we aimed to find out how an observer's brain reacts to a speaker's eye blinks in the presence of other audiovisual information. Magnetoencephalographic brain responses along with eye gaze were recorded from 13 adults who watched a video of a person telling a story. The video was presented first without sound (visual), then with sound (audiovisual), and finally the audio story was presented with a still-frame picture on the screen (audio control). The viewers mainly gazed at the eye region of the speaker. Their saccades were suppressed at about 180 ms after the start of the speaker's blinks, a subsequent increase of saccade occurence to the base level, or higher, at around 340 ms. The suppression occurred in visual and audiovisual conditions but not during the control audio presentation. Prominent brain responses to blinks peaked in the viewer's occipital cortex at about 250 ms, with no differences in mean peak amplitudes or latencies between visual and audiovisual conditions. During the audiovisual, but not visual-only, presentation, the responses were the stronger the more empathetic the subject was according to the Empathic Concern score of the Interpersonal Reactivity Index questionnaire (Spearman's rank correlation, 0.73). The other person's eye blinks, nonverbal signs that often go unnoticed, thus elicited clear brain responses even in the presence of attention-attracting audiovisual information from the narrative, with stronger responses in people with higher empathy scores.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marx2015,

title = {Reward modulates perception in binocular rivalry},

author = {Svenja Marx and Wolfgang Einhäuser},

doi = {10.1167/15.1.11},

year  = {2015},

date = {2015-01-01},

journal = {Journal of Vision},

volume = {15},

number = {1},

pages = {1–13},

abstract = {Our perception does not provide us with an exact imprint of the outside world, but is continuously adapted to our internal expectations, task sets, and behavioral goals. Although effects of reward—or value in general—on perception therefore seem likely, how valuation modulates perception and how such modulation relates to attention is largely unknown. We probed effects of reward on perception by using a binocular-rivalry paradigm. Distinct gratings drifting in opposite directions were presented to each observer's eyes. To objectify their subjective perceptual experience, the optokinetic nystagmus was used as measure of current perceptual dominance. In a first experiment, one of the percepts was either rewarded or attended. We found that reward and attention similarly biased perception. In a second experiment, observers performed an attentionally demanding task either on the rewarded stimulus, the other stimulus, or both. We found that—on top of an attentional effect on perception—at each level of attentional load, reward still modulated perception by increasing the dominance of the rewarded percept. Similarly, penalizing one percept increased dominance of the other at each level of attentional load. In turn, rewarding—and similarly nonpunishing—a percept yielded performance benefits that are typically associated with selective attention. In conclusion, our data show that value modulates perception in a similar way as the volitional deployment of attention, even though the relative effect of value is largely unaffected by an attention task.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ajina2015,

title = {Motion area V5/MT+ response to global motion in the absence of V1 resembles early visual cortex},

author = {Sara Ajina and Christopher Kennard and Geraint Rees and Holly Bridge},

doi = {10.1093/brain/awu328},

year  = {2015},

date = {2015-01-01},

journal = {Brain},

volume = {138},

number = {1},

pages = {164–178},

abstract = {Motion area V5/MT+ shows a variety of characteristic visual responses, often linked to perception, which are heavily influenced by its rich connectivity with the primary visual cortex (V1). This human motion area also receives a number of inputs from other visual regions, including direct subcortical connections and callosal connections with the contralateral hemisphere. Little is currently known about such alternative inputs to V5/MT+ and how they may drive and influence its activity. Using functional magnetic resonance imaging, the response of human V5/MT+ to increasing the proportion of coherent motion was measured in seven patients with unilateral V1 damage acquired during adulthood, and a group of healthy age-matched controls. When V1 was damaged, the typical V5/MT+ response to increasing coherence was lost. Rather, V5/MT+ in patients showed a negative trend with coherence that was similar to coherence-related activity in V1 of healthy control subjects. This shift to a response-pattern more typical of early visual cortex suggests that in the absence of V1, V5/MT+ activity may be shaped by similar direct subcortical input. This is likely to reflect intact residual pathways rather than a change in connectivity, and has important implications for blindsight function. It also confirms predictions that V1 is critically involved in normal V5/MT+ global motion processing, consistent with a convergent model of V1 input to V5/MT+. Historically, most attempts to model cortical visual responses do not consider the contribution of direct subcortical inputs that may bypass striate cortex, such as input to V5/MT+. We have shown that the signal change driven by these non-striate pathways can be measured, and suggest that models of the intact visual system may benefit from considering their contribution.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ajina2015b,

title = {Abnormal contrast responses in the extrastriate cortex of blindsight patients},

author = {Sara Ajina and Geraint Rees and Christopher Kennard and Holly Bridge},

doi = {10.1523/JNEUROSCI.3075-14.2015},

year  = {2015},

date = {2015-01-01},

journal = {Journal of Neuroscience},

volume = {35},

number = {21},

pages = {8201–8213},

abstract = {When the human primary visual cortex (V1) is damaged, the dominant geniculo-striate pathway can no longer convey visual information to the occipital cortex. However, many patients with such damage retain some residual visual function that must rely on an alternative pathway directly to extrastriate occipital regions. This residual vision is most robust for moving stimuli, suggesting a role for motion area hMT+. However, residual vision also requires high-contrast stimuli, which is inconsistent with hMT+ sensitivity to contrast in which even low-contrast levels elicit near-maximal neural activation. We sought to investigate this discrepancy by measuring behavioral and neural responses to increasing contrast in patients with V1 damage. Eight patients underwent behavioral testing and functional magnetic resonance imaging to record contrast sensitivity in hMT+ of their damaged hemisphere, using Gabor stimuli with a spatial frequency of 1 cycle/degrees. The responses from hMT+ of the blind hemisphere were compared with hMT+ and V1 responses in the sighted hemisphere of patients and a group of age-matched controls. Unlike hMT+, neural responses in V1 tend to increase linearly with increasing contrast, likely reflecting a dominant parvocellular channel input. Across all patients, the responses in hMT+ of the blind hemisphere no longer showed early saturation but increased linearly with contrast. Given the spatiotemporal parameters used in this study and the known direct subcortical projections from the koniocellular layers of the lateral geniculate nucleus to hMT+, we propose that this altered contrast sensitivity in hMT+ could be consistent with input from the koniocellular pathway.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Andoh2015,

title = {Asymmetric interhemispheric transfer in the auditory network: Evidence from TMS, resting-state fMRI, and diffusion imaging},

author = {Jamila Andoh and Reiko Matsushita and Robert J. Zatorre},

doi = {10.1523/JNEUROSCI.2333-15.2015},

year  = {2015},

date = {2015-01-01},

journal = {Journal of Neuroscience},

volume = {43},

number = {43},

pages = {14602–14611},

abstract = {Hemispheric asymmetries in human auditory cortical function and structure are still highly debated. Brain stimulation approaches can complement correlational techniques by uncovering causal influences. Previous studies have shown asymmetrical effects of transcranial magnetic stimulation (TMS) on task performance, but it is unclear whether these effects are task-specific or reflect intrinsic network properties. To test how modulation of auditory cortex (AC) influences functional networks and whether this influence is asymmetrical, the present study measured resting-state fMRI connectivity networks in 17 healthy volunteers before and immediately after TMS (continuous theta burst stimulation) to the left or right AC, and the vertex as a control. We also examined the relationship between TMS-induced interhemispheric signal propagation and anatomical properties of callosal auditory fibers as measured with diffusion-weighted MRI. We found that TMS to the right AC, but not the left, resulted in widespread connectivity decreases in auditory- and motor-related networks in the resting state. Individual differences in the degree of change in functional connectivity between auditory cortices after TMS applied over the right AC were negatively related to the volume of callosal auditory fibers. The findings show that TMS-induced network modulation occurs, even in the absence of an explicit task, and that the magnitude of the effect differs across individuals as a function of callosal structure, supporting a role for the corpus callosum in mediating functional asymmetry. The findings support theoretical models emphasizing hemispheric differences in network organization and are of practical significance in showing that brain stimulation studies need to take network-level effects into account.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bao2015,

title = {Using an achiasmic human visual system to quantify the relationship between the fMRI BOLD signal and neural response},

author = {Pinglei Bao and Christopher J. Purington and Bosco S. Tjan},

doi = {10.7554/eLife.09600},

year  = {2015},

date = {2015-01-01},

journal = {eLife},

volume = {4},

number = {NOVEMBER2015},

pages = {1–21},

abstract = {Achiasma in humans causes gross mis-wiring of the retinal-fugal projection, resulting in overlapped cortical representations of left and right visual hemifields. We show that in areas V1-V3 this overlap is due to two co-located but non-interacting populations of neurons, each with a receptive field serving only one hemifield. Importantly, the two populations share the same local vascular control, resulting in a unique organization useful for quantifying the relationship between neural and fMRI BOLD responses without direct measurement of neural activity. Specifically, we can non-invasively double local neural responses by stimulating both neuronal populations with identical stimuli presented symmetrically across the vertical meridian to both visual hemifields, versus one population by stimulating in one hemifield. Measurements from a series of such doubling experiments show that the amplitude of BOLD response is proportional to approximately 0.5 power of the underlying neural response. Reanalyzing published data shows that this inferred relationship is general.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Brascamp2015,

title = {Negligible fronto-parietal BOLD activity accompanying unreportable switches in bistable perception},

author = {Jan Brascamp and Randolph Blake and Tomas Knapen},

doi = {10.1038/nn.4130},

year  = {2015},

date = {2015-01-01},

journal = {Nature Neuroscience},

volume = {18},

number = {11},

pages = {1672–1678},

publisher = {Nature Publishing Group},

abstract = {The human brain's executive systems have a vital role in deciding and selecting among actions. Selection among alternatives also occurs in the perceptual domain; for instance, when perception switches between interpretations during perceptual bistability. Whether executive systems also underlie this functionality remains debated, with known fronto-parietal concomitants of perceptual switches being variously interpreted as reflecting the switches' cause or as reflecting their consequences. We developed a procedure in which the two eyes receive different inputs and perception demonstrably switches between these inputs, yet the switches themselves are so inconspicuous as to become unreportable, minimizing their executive consequences. Fronto-parietal fMRI BOLD responses that accompanied perceptual switches were similarly minimized in this procedure, indicating that these reflect the switches' consequences rather than their cause. We conclude that perceptual switches do not always rely on executive brain areas and that processes responsible for selection among alternatives may operate outside the brain's executive systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Buyukturkoglu2015,

title = {Self-regulation of anterior insula using real-time fMRI and its behavioral effects in obsessive compulsive disorder: A feasibility study},

author = {Korhan Buyukturkoglu and Hans Roettgers and Jens Sommer and Mohit Rana and Leonie Dietzsch and Ezgi Belkis Arikan and Ralf Veit and Rahim Malekshahi and Tilo Kircher and Niels Birbaumer and Ranganatha Sitaram and Sergio Ruiz},

doi = {10.1371/journal.pone.0135872},

year  = {2015},

date = {2015-01-01},

journal = {PLoS ONE},

volume = {10},

number = {8},

pages = {e0135872},

abstract = {Introduction: Obsessive-compulsive disorder (OCD) is a common and chronic condition that can have disabling effects throughout the patient's lifespan. Frequent symptoms among OCD patients include fear of contamination and washing compulsions. Several studies have shown a link between contamination fears, disgust over-reactivity, and insula activation in OCD. In concordance with the role of insula in disgust processing, new neural models based on neuroimaging studies suggest that abnormally high activations of insula could be implicated in OCD psychopathology, at least in the subgroup of patients with contamination fears and washing compulsions. Methods: In the current study, we used a Brain Computer Interface (BCI) based on real-time func- tional magnetic resonance imaging (rtfMRI) to aid OCD patients to achieve down-regula- tion of the Blood Oxygenation Level Dependent (BOLD) signal in anterior insula. Our first aim was to investigate whether patients with contamination obsessions and washing com- pulsions can learn to volitionally decrease (down-regulate) activity in the insula in the pres- ence of disgust/anxiety provoking stimuli. Our second aimwas to evaluate the effect of down-regulation on clinical, behavioural and physiological changes pertaining to OCD symptoms. Hence, several pre- and post-training measures were performed, i.e., con- fronting the patient with a disgust/anxiety inducing real-world object (Ecological Disgust Test), and subjective rating and physiological responses (heart rate, skin conductance level) of disgust towards provoking pictures. Results: Results of this pilot study, performed in 3 patients (2 females), show that OCD patients can gain self-control of the BOLD activity of insula, albeit to different degrees. In two patients positive changes in behaviour in the EDT were observed following the rtfMRI trainings. Behavioural changes were also confirmed by reductions in the negative valence and in the subjective perception of disgust towards symptom provoking images. Conclusion: Although preliminary, results of this study confirmed that insula down-regulation is possible in patients suffering from OCD, and that volitional decreases of insula activation could be used for symptom alleviation in this disorder.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Caruana2015,

title = {A frontotemporoparietal network common to initiating and responding to joint attention bids},

author = {Nathan Caruana and Jon Brock and Alexandra Woolgar},

doi = {10.1016/j.neuroimage.2014.12.041},

year  = {2015},

date = {2015-01-01},

journal = {NeuroImage},

volume = {108},

pages = {34–46},

publisher = {Elsevier B.V.},

abstract = {Joint attention is a fundamental cognitive ability that supports daily interpersonal relationships and communication. The Parallel Distributed Processing model (PDPM) postulates that responding to (RJA) and initiating (IJA) joint attention are predominantly supported by posterior-parietal and frontal regions respectively. It also argues that these neural networks integrate during development, supporting the parallel processes of self- and other-attention representation during interactions. However, direct evidence for the PDPM is limited due to a lack of ecologically valid experimental paradigms that can capture both RJA and IJA. Building on existing interactive approaches, we developed a virtual reality paradigm where participants engaged in an online interaction to complete a cooperative task. By including tightly controlled baseline conditions to remove activity associated with non-social task demands, we were able to directly contrast the neural correlates of RJA and IJA to determine whether these processes are supported by common brain regions. Both RJA and IJA activated broad frontotemporoparietal networks. Critically, a conjunction analysis identified that a subset of these regions were common to both RJA and IJA. This right-lateralised network included the dorsal portion of the middle frontal gyrus (MFG), inferior frontal gyrus (IFG), middle temporal gyrus (MTG), precentral gyrus, posterior superior temporal sulcus (pSTS), temporoparietal junction (TPJ) and precuneus. Additional activation was observed in this network for IJA relative to RJA at MFG, IFG, TPJ and precuneus. This is the first imaging study to directly investigate the neural correlates common to RJA and IJA engagement, and thus support the assumption that a broad integrated network underlies the parallel aspects of both initiating and responding to joint attention.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Choi2015,

title = {Neural correlates of active vision: An fMRI comparison of natural reading and scene viewing},

author = {Wonil Choi and John M. Henderson},

doi = {10.1016/j.neuropsychologia.2015.05.027},

year  = {2015},

date = {2015-01-01},

journal = {Neuropsychologia},

volume = {75},

pages = {109–118},

publisher = {Elsevier},

abstract = {Theories of eye movement control during active vision tasks such as reading and scene viewing have primarily been developed and tested using data from eye tracking and computational modeling, and little is currently known about the neurocognition of active vision. The current fMRI study was conducted to examine the nature of the cortical networks that are associated with active vision. Subjects were asked to read passages for meaning and view photographs of scenes for a later memory test. The eye movement control network comprising frontal eye field (FEF), supplementary eye fields (SEF), and intraparietal sulcus (IPS), commonly activated during single-saccade eye movement tasks, were also involved in reading and scene viewing, suggesting that a common control network is engaged when eye movements are executed. However, the activated locus of the FEF varied across the two tasks, with medial FEF more activated in scene viewing relative to passage reading and lateral FEF more activated in reading than scene viewing. The results suggest that eye movements during active vision are associated with both domain-general and domain-specific components of the eye movement control network.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Clavagnier2015,

title = {Is the cortical deficit in amblyopia due to reduced cortical magnification, loss of neural resolution, or neural disorganization?},

author = {S. Clavagnier and Serge O. Dumoulin and R. F. Hess},

doi = {10.1523/JNEUROSCI.1101-15.2015},

year  = {2015},

date = {2015-01-01},

journal = {Journal of Neuroscience},

volume = {35},

number = {44},

pages = {14740–14755},

abstract = {The neural basis of amblyopia is a matter of debate. The following possibilities have been suggested: loss of foveal cells, reduced cortical magnification, loss of spatial resolution of foveal cells, and topographical disarray in the cellular map. To resolve this we undertook a population receptive field (pRF) functional magnetic resonance imaging analysis in the central field in humans with moderate-to-severe amblyopia. We measured the relationship between averaged pRF size and retinal eccentricity in retinotopic visual areas. Results showed that cortical magnification is normal in the foveal field of strabismic amblyopes. However, the pRF sizes are enlarged for the amblyopic eye. We speculate that the pRF enlargement reflects loss of cellular resolution or an increased cellular positional disarray within the representation of the amblyopic eye.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Brouwer2015,

title = {The Müller-Lyer illusion affects visuomotor updating in the dorsal visual stream},

author = {Anouk J. Brouwer and Jeroen B. J. Smeets and Tjerk P. Gutteling and I. Toni and W. Pieter Medendorp},

doi = {10.1016/j.neuropsychologia.2015.08.012},

year  = {2015},

date = {2015-01-01},

journal = {Neuropsychologia},

volume = {77},

pages = {119–127},

publisher = {Elsevier},

abstract = {To guide our actions, the brain has developed mechanisms to code target locations in egocentric coordinates (i.e., with respect to the observer), and to update these when the observer moves. The latter mechanism, called visuomotor updating, is implemented in the dorsal visual stream of the brain. In contrast, the ventral visual stream is assumed to transform target locations into an allocentric reference frame that is highly sensitive to visual contextual illusions. Here, we tested the effect of the Müller-Lyer illusion on visuomotor updating in a double-step saccade task. Using the same paradigm in a 3T fMRI scanner, we investigated the effect of the illusion on the neural correlate of the updating process. Participants briefly viewed the Brentano version of the Müller-Lyer illusion with a target at its middle vertex, while fixating at one of the two endpoints of the illusion. Shortly after the disappearance of the stimulus, the eyes' fixation point moved to a position outside the illusion. After a delay, participants made a saccade to the remembered position of the target. The landing position of this saccade was systematically displaced in a manner congruent with the perceptual illusion, showing that visuomotor updating is affected by the illusion. fMRI results showed that the BOLD response in the occipito-parietal cortex (area V7) and the intraparietal sulcus related to planning of the saccade to the updated target was also modulated by the configuration of the illusion. This suggests that the dorsal visual stream represents perceived rather than physical locations of remembered saccade targets.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Elkhetali2015,

title = {Early visual cortex reflects initiation and maintenance of task set},

author = {Abdurahman S. Elkhetali and Ryan J. Vaden and Sean M. Pool and Kristina M. Visscher},

doi = {10.1016/j.neuroimage.2014.11.061},

year  = {2015},

date = {2015-01-01},

journal = {NeuroImage},

volume = {107},

pages = {277–288},

publisher = {Elsevier B.V.},

abstract = {The human brain is able to process information flexibly, depending on a person's task. The mechanisms underlying this ability to initiate and maintain a task set are not well understood, but they are important for understanding the flexibility of human behavior and developing therapies for disorders involving attention. Here we investigate the differential roles of early visual cortical areas in initiating and maintaining a task set.Using functional Magnetic Resonance Imaging (fMRI), we characterized three different components of task set-related, but trial-independent activity in retinotopically mapped areas of early visual cortex, while human participants performed attention demanding visual or auditory tasks. These trial-independent effects reflected: (1) maintenance of attention over a long duration, (2) orienting to a cue, and (3) initiation of a task set. Participants performed tasks that differed in the modality of stimulus to be attended (auditory or visual) and in whether there was a simultaneous distractor (auditory only, visual only, or simultaneous auditory and visual). We found that patterns of trial-independent activity in early visual areas (V1, V2, V3, hV4) depend on attended modality, but not on stimuli. Further, different early visual areas play distinct roles in the initiation of a task set. In addition, activity associated with maintaining a task set tracks with a participant's behavior. These results show that trial-independent activity in early visual cortex reflects initiation and maintenance of a person's task set.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Aamand2014,

title = {Dietary nitrate facilitates an acetazolamide-induced increase in cerebral blood flow during visual stimulation},

author = {Rasmus Aamand and Yi-Ching Lynn Ho and Thomas Dalsgaard and Andreas Roepstorff and Torben E. Lund},

doi = {10.1152/japplphysiol.00797.2013},

year  = {2014},

date = {2014-02-01},

journal = {Journal of Applied Physiology},

volume = {116},

number = {3},

pages = {267–273},

abstract = {The carbonic anhydrase (CA) inhibitor acetazolamide (AZ) is used routinely to estimate cerebrovascular reserve capacity in patients, as it reliably increases cerebral blood flow (CBF). However, the mechanism by which AZ accomplishes this CBF increase is not entirely understood. We recently discovered that CA can produce nitric oxide (NO) from nitrite, and that AZ enhances this NO production in vitro. In fact, this interaction between AZ and CA accounted for a large part of AZ's vasodilatory action, which fits well with the known vasodilatory potency of NO. The present study aimed to assess whether AZ acts similarly in vivo in the human cerebrovascular system. Hence, we increased or minimized the dietary intake of nitrate in 20 healthy male participants, showed them a full-field flickering dartboard, and measured their CBF response to this visual stimulus with arterial spin labeling. Doing so, we found a significant positive interaction between the dietary intake of nitrate and the CBF modulation afforded by AZ during visual stimulation. In addition, but contrary to studies conducted in elderly participants, we report no effect of nitrate intake on resting CBF in healthy human participants. The present study provides in vivo support for an enhancing effect of AZ on the NO production from nitrite catalyzed by CA in the cerebrovascular system. Furthermore, our results, in combination with the results of other groups, indicate that nitrate may have significant importance to vascular function when the cerebrovascular system is challenged by age or disease.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Barany2014,

title = {Feature Iinteractions enable decoding of sensorimotor transformations for goal-directed movement},

author = {D. A. Barany and V. Della-Maggiore and Shivakumar Viswanathan and M. Cieslak and Scott T. Grafton},

doi = {10.1523/JNEUROSCI.5173-13.2014},

year  = {2014},

date = {2014-01-01},

journal = {Journal of Neuroscience},

volume = {34},

number = {20},

pages = {6860–6873},

abstract = {Neurophysiology and neuroimaging evidence shows that the brain represents multiple environmental and body-related features to compute transformations from sensory input to motor output. However, it is unclear how these features interact during goal-directed movement. To investigate this issue, we examined the representations of sensory and motor features of human hand movements within the left-hemisphere motor network. In a rapid event-related fMRI design, we measured cortical activity as participants performed right-handed movements at the wrist, with either of two postures and two amplitudes, to move a cursor to targets at different locations. Using a multivoxel analysis technique with rigorous generalization tests, we reliably distinguished representations of task-related features (primarily target location, movement direction, and posture) in multiple regions. In particular, we identified an interaction between target location and movement direction in the superior parietal lobule, which may underlie a transformation from the location of the target in space to a movement vector. In addition, we found an influence of posture on primary motor, premotor, and parietal regions. Together, these results reveal the complex interactions between different sensory and motor features that drive the computation of sensorimotor transformations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bridge2014,

title = {Hippocampal binding of novel information with dominant memory traces can support both memory stability and change},

author = {D. J. Bridge and Joel L. Voss},

doi = {10.1523/JNEUROSCI.3819-13.2014},

year  = {2014},

date = {2014-01-01},

journal = {Journal of Neuroscience},

volume = {34},

number = {6},

pages = {2203–2213},

abstract = {Memory stability and change are considered opposite outcomes. We tested the counterintuitive notion that both depend on one process: hippocampal binding of memory features to associatively novel information, or associative novelty binding (ANB). Building on the idea that dominant memory features, or “traces,” are most susceptible to modification, we hypothesized that ANB would selectively involve dominant traces. Therefore, memory stability versus change should depend on whether the currently dominant trace is old versus updated; in either case, novel information will be bound with it, causing either maintenance (when old) or change (when updated). People in our experiment studied objects at locations within scenes (contexts). During reactivation in a new context, subjects moved studied objects to new locations either via active location recall or by passively dragging objects to predetermined locations. After active reactivation, the new object location became dominant in memory, whereas after passive reactivation, the old object location maintained dominance. In both cases, hippocampal ANB bound the currently dominant object-location memory with a context with which it was not paired previously (i.e., associatively novel). Stability occurred in the passive condition when ANB united the dominant original location trace with an associatively novel newer context. Change occurred in the active condition when ANB united the dominant updated object location with an associatively novel and older context. Hippocampal ANB of the currently dominant trace with associatively novel contextual information thus provides a single mechanism to support memory stability and change, with shifts in trace dominance during reactivation dictating the outcome.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Choi2014c,

title = {The neural substrates of natural reading: A comparison of normal and nonword text using eyetracking and fMRI},

author = {Wonil Choi and Rutvik H. Desai and John M. Henderson},

doi = {10.3389/fnhum.2014.01024},

year  = {2014},

date = {2014-01-01},

journal = {Frontiers in Human Neuroscience},

volume = {8},

pages = {1024},

abstract = {Most previous studies investigating the neural correlates of reading have presented text using serial visual presentation (SVP), which may not fully reflect the underlying processes of natural reading. In the present study, eye movements and BOLD data were collected while subjects either read normal paragraphs naturally or moved their eyes through "paragraphs" of pseudo-text (pronounceable pseudowords or consonant letter strings) in two pseudo-reading conditions. Eye movement data established that subjects were reading and scanning the stimuli normally. A conjunction fMRI analysis across natural- and pseudo-reading showed that a common eye-movement network including frontal eye fields (FEF), supplementary eye fields (SEF), and intraparietal sulci was activated, consistent with previous studies using simpler eye movement tasks. In addition, natural reading versus pseudo-reading showed different patterns of brain activation: normal reading produced activation in a well-established language network that included superior temporal gyrus/sulcus, middle temporal gyrus (MTG), angular gyrus (AG), inferior frontal gyrus, and middle frontal gyrus, whereas pseudo-reading produced activation in an attentional network that included anterior/posterior cingulate and parietal cortex. These results are consistent with results found in previous single-saccade eye movement tasks and SVP reading studies, suggesting that component processes of eye-movement control and language processing observed in past fMRI research generalize to natural reading. The results also suggest that combining eyetracking and fMRI is a suitable method for investigating the component processes of natural reading in fMRI research.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lahnakoski2014,

title = {Synchronous brain activity across individuals underlies shared psychological perspectives},

author = {Juha M. Lahnakoski and Enrico Glerean and Iiro P. Jääskeläinen and Jukka Hyönä and Riitta Hari and Mikko Sams and Lauri Nummenmaa},

doi = {10.1016/j.neuroimage.2014.06.022},

year  = {2014},

date = {2014-01-01},

journal = {NeuroImage},

volume = {100},

pages = {316–324},

publisher = {Elsevier B.V.},

abstract = {For successful communication, we need to understand the external world consistently with others. This task requires sufficiently similar cognitive schemas or psychological perspectives that act as filters to guide the selection, interpretation and storage of sensory information, perceptual objects and events. Here we show that when individuals adopt a similar psychological perspective during natural viewing, their brain activity becomes synchronized in specific brain regions. We measured brain activity with functional magnetic resonance imaging (fMRI) from 33 healthy participants who viewed a 10-min movie twice, assuming once a 'social' (detective) and once a 'non-social' (interior decorator) perspective to the movie events. Pearson's correlation coefficient was used to derive multisubject voxelwise similarity measures (inter-subject correlations; ISCs) of functional MRI data. We used k-nearest-neighbor and support vector machine classifiers as well as a Mantel test on the ISC matrices to reveal brain areas wherein ISC predicted the participants' current perspective. ISC was stronger in several brain regions-most robustly in the parahippocampal gyrus, posterior parietal cortex and lateral occipital cortex-when the participants viewed the movie with similar rather than different perspectives. Synchronization was not explained by differences in visual sampling of the movies, as estimated by eye gaze. We propose that synchronous brain activity across individuals adopting similar psychological perspectives could be an important neural mechanism supporting shared understanding of the environment.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lawson2014,

title = {The habenula encodes negative motivational value associated with primary punishment in humans},

author = {Rebecca P. Lawson and Ben Seymour and Eleanor Loh and Antoine Lutti and Raymond J. Dolan and Peter Dayan and Nikolaus Weiskopf and Jonathan P. Roiser},

doi = {10.1073/pnas.1323586111},

year  = {2014},

date = {2014-01-01},

journal = {Proceedings of the National Academy of Sciences},

volume = {111},

number = {32},

pages = {11858–11863},

abstract = {Learning what to approach, and what to avoid, involves assigning value to environmental cues that predict positive and negative events. Studies in animals indicate that the lateral habenula encodes the previously learned negative motivational value of stimuli. However, involvement of the habenula in dynamic trial-by-trial aversive learning has not been assessed, and the functional role of this structure in humans remains poorly characterized, in part, due to its small size. Using high-resolution functional neuroimaging and computational modeling of reinforcement learning, we demonstrate positive habenula responses to the dynamically changing values of cues signaling painful electric shocks, which predict behavioral suppression of responses to those cues across individuals. By contrast, negative habenula responses to monetary reward cue values predict behavioral invigoration. Our findings show that the habenula plays a key role in an online aversive learning system and in generating associated motivated behavior in humans.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lukasova2014,

title = {Test-retest reliability of fMRI activation generated by different saccade tasks},

author = {Katerina Lukasova and Jens Sommer and Mariana P. Nucci-Da-Silva and Gilson Vieira and Marius Blanke and Frank Bremmer and João R. Sato and Tilo Kircher and Edson Amaro},

doi = {10.1002/jmri.24369},

year  = {2014},

date = {2014-01-01},

journal = {Journal of Magnetic Resonance Imaging},

volume = {40},

number = {1},

pages = {37–46},

abstract = {PURPOSE: To assess the reproducibility of brain-activation and eye-movement patterns in a saccade paradigm when comparing subjects, tasks, and magnetic resonance (MR) systems. MATERIALS AND METHODS: Forty-five healthy adults at two different sites (n = 45) performed saccade tasks with varying levels of target predictability: predictable (PRED), position predictable (pPRED), time predictable (tPRED), and prosaccade (SAC). Eye-movement pattern was tested with a repeated-measures analysis of variance. Activation maps reproducibility were estimated with the cluster overlap Jaccard index and signal variance coefficient of determination for within-subjects test-retest data, and for between-subjects data from the same and different sites. RESULTS: In all groups latencies increased with decreasing target predictability: PRED < pPRED < tPRED < SAC (P < 0,001). Activation overlap was good to fair (>0.40) in all tasks in the within-subjects test-retest comparisons and poor (<0.40) in the tPRED for different subjects. The overlap of the different tasks for within-groups data was higher (0.40-0.68) than for the between-groups data (0.30-0.50). Activation consistency was 60-85% in the same subjects, 50-79% in different subjects, and 50-80% in different sites. In SAC, the activation found in the same and in different subjects was more consistent than in other tasks (50-80%). CONCLUSION: The predictive saccade tasks produced evidence for brain-activation and eye-movement reproducibility},

keywords = {},

pubstate = {published},

tppubtype = {article}

}