All EyeLink Publications
All 12,000+ peer-reviewed EyeLink research publications up until 2023 (with some early 2024s) are listed below by year. You can search the publications library using keywords such as Visual Search, Smooth Pursuit, Parkinson’s, etc. You can also search for individual author names. Eye-tracking studies grouped by research area can be found on the solutions pages. If we missed any EyeLink eye-tracking papers, please email us!
2016 |
Jeff Moher; Joo-Hyun Song Target selection biases from recent experience transfer across effectors Journal Article In: Attention, Perception, and Psychophysics, vol. 78, no. 2, pp. 415–426, 2016. @article{Moher2016, Target selection is often biased by an observer's recent experiences. However, not much is known about whether these selection biases influence behavior across different effectors. For example, does looking at a red object make it easier to subsequently reach towards another red object? In the current study, we asked observers to find the uniquely colored target object on each trial. Randomly intermixed pre-trial cues indicated the mode of action: either an eye movement or a visually guided reach movement to the target. In Experiment 1, we found that priming of popout, reflected in faster responses following repetition of the target color on consecutive trials, occurred regardless of whether the effector was repeated from the previous trial or not. In Experiment 2, we examined whether an inhibitory selection bias away from a feature could transfer across effectors. While priming of popout reflects both enhancement of the repeated target features and suppression of the repeated distractor features, the distractor previewing effect isolates a purely inhibitory component of target selection in which a previewed color is presented in a homogenous display and subsequently inhibited. Much like priming of popout, intertrial suppression biases in the distractor previewing effect transferred across effectors. Together, these results suggest that biases for target selection driven by recent trial history transfer across effectors. This indicates that representations in memory that bias attention towards or away from specific features are largely independent from their associated actions. |
Robert M. Mok; Nicholas E. Myers; George Wallis; Anna C. Nobre Behavioral and neural markers of flexible attention over working memory in aging Journal Article In: Cerebral Cortex, vol. 26, no. 4, pp. 1831–1842, 2016. @article{Mok2016, 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. |
Charlotte B. Montgomery; Carrie Allison; Meng Chuan Lai; Sarah Cassidy; Peter E. Langdon; Simon Baron-Cohen Do adults with high functioning Autism or Asperger syndrome differ in empathy and emotion recognition? Journal Article In: Journal of Autism and Developmental Disorders, vol. 46, no. 6, pp. 1931–1940, 2016. @article{Montgomery2016, The present study examined whether adults with high functioning autism (HFA) showed greater difficulties in (1) their self-reported ability to empathise with others and/or (2) their ability to read mental states in others' eyes than adults with Asperger syndrome (AS). The Empathy Quotient (EQ) and ‘Reading the Mind in the Eyes' Test (Eyes Test) were compared in 43 adults with AS and 43 adults with HFA. No significant difference was observed on EQ score between groups, while adults with AS performed significantly better on the Eyes Test than those with HFA. This suggests that adults with HFA may need more support, particularly in mentalizing and complex emotion recognition, and raises questions about the existence of subgroups within autism spectrum conditions. |
Luis Morales; Daniela Paolieri; Paola E. Dussias; Jorge R. Valdés Kroff; Chip Gerfen; María Teresa Bajo The gender congruency effect during bilingual spoken-word recognition Journal Article In: Bilingualism: Language and Cognition, vol. 19, no. 2, pp. 294–310, 2016. @article{Morales2016, We investigate the 'gender-congruency' effect during a spoken-word recognition task using the visual world paradigm. Eye movements of Italian-Spanish bilinguals and Spanish monolinguals were monitored while they viewed a pair of objects on a computer screen. Participants listened to instructions in Spanish (encuentra la bufanda / 'find the scarf') and clicked on the object named in the instruction. Grammatical gender of the objects' name was manipulated so that pairs of objects had the same (congruent) or different (incongruent) gender in Italian, but gender in Spanish was always congruent. Results showed that bilinguals, but not monolinguals, looked at target objects less when they were incongruent in gender, suggesting a between-language gender competition effect. In addition, bilinguals looked at target objects more when the definite article in the spoken instructions provided a valid cue to anticipate its selection (different-gender condition). The temporal dynamics of gender processing and cross-language activation in bilinguals are discussed. |
Michael Morgan; Kai Schreiber; J. A. Solomon Low-level mediation of directionally specific motion aftereffects: Motion perception is not necessary Journal Article In: Attention, Perception, and Psychophysics, vol. 78, no. 8, pp. 2621–2632, 2016. @article{Morgan2016, Previous psychophysical experiments with normal human observers have shown that adaptation to a moving dot stream causes directionally specific repulsion in the perceived angle of a subsequently viewed moving probe. In this study, we used a two-alternative forced choice task with roving pedestals to determine the conditions that are necessary and sufficient for producing directionally specific repulsion with compound adaptors, each of which contains two oppositely moving, differently colored component streams. Experiment 1 provided a demonstration of repulsion between single-component adaptors and probes moving at approximately 90° or 270°. In Experiment 2, oppositely moving dots in the adaptor were paired to preclude the appearance of motion. Nonetheless, repulsion remained strong when the angle between each probe stream and one component was approximately 30°. In Experiment 3, adapting dot pairs were kept stationary during their limited lifetimes. Their orientation content alone proved insufficient for producing repulsion. In Experiments 4–6, the angle between the probe and both adapting components was approximately 90° or 270°. Directional repulsion was found when observers were asked to visually track one of the adapting components (Exp. 6), but not when they were asked to attentionally track it (Exp. 5), nor while they passively viewed the adaptor (Exp. 4). Our results are consistent with a low-level mechanism for motion adaptation. This mechanism is not selective for stimulus color and is not susceptible to attentional modulation. The most likely cortical locus of adaptation is area V1. |
Chie Nakamura; Manabu Arai Persistence of initial misanalysis with no referential ambiguity Journal Article In: Cognitive Science, vol. 40, no. 4, pp. 909–940, 2016. @article{Nakamura2016, Previous research reported that in processing structurally ambiguous sentences comprehenders often preserve an initial incorrect analysis even after adopting a correct analysis following structural disambiguation. One criticism is that the sentences tested in previous studies involved referential ambiguity and allowed comprehenders to make inferences about the initial interpretation using pragmatic information, suggesting the possibility that the initial analysis persisted due to comprehenders' pragmatic inference but not to their failure to perform complete reanalysis of the initial misanalysis. Our study investigated this by testing locally ambiguous relative clause sentences in Japanese, in which the initial misinterpretation contradicts the correct interpretation. Our study using a self-paced reading technique demonstrated evidence for the persistence of the initial analysis with this structure. The results from an eye-tracking study further suggested that the phenomenon directly reflected the amount of support given to the initial incorrect analysis prior to disambiguating information: The more supported the incorrect main clause analysis was, the more likely comprehenders were to preserve the analysis even after the analysis was falsified. Our results thus demonstrated that the preservation of the initial analysis occurs not due to referential ambiguities but to comprehenders' difficulty to fully revise the highly supported initial interpretation. |
Hamidreza Namazi; Vladimir V. Kulish; Amin Akrami The analysis of the influence of fractal structure of stimuli on fractal dynamics in fixational eye movements and EEG signal Journal Article In: Scientific Reports, vol. 6, pp. 26639, 2016. @article{Namazi2016, One of the major challenges in vision research is to analyze the effect of visual stimuli on human vision. However, no relationship has been yet discovered between the structure of the visual stimulus, and the structure of fixational eye movements. This study reveals the plasticity of human fixational eye movements in relation to the ‘complex' visual stimulus. We demonstrated that the fractal temporal structure of visual dynamics shifts towards the fractal dynamics of the visual stimulus (image). The results showed that images with higher complexity (higher fractality) cause fixational eye movements with lower fractality. Considering the brain, as the main part of nervous system that is engaged in eye movements, we analyzed the governed Electroencephalogram (EEG) signal during fixation. We have found out that there is a coupling between fractality of image, EEG and fixational eye movements. The capability observed in this research can be further investigated and applied for treatment of different vision disorders. |
Marko Nardini; Jennifer Bales; Denis Mareschal Integration of audio-visual information for spatial decisions in children and adults Journal Article In: Developmental Science, vol. 19, no. 5, pp. 803–816, 2016. @article{Nardini2016, In adults, decisions based on multisensory information can be faster and/or more accurate than those relying on a single sense. However, this finding varies significantly across development. Here we studied speeded responding to audio-visual targets, a key multisensory function whose development remains unclear. We found that when judging the locations of targets, children aged 4 to 12 years and adults had faster and less variable response times given auditory and visual information together compared with either alone. Comparison of response time distributions with model predictions indicated that children at all ages were integrating (pooling) sensory information to make decisions but that both the overall speed and the efficiency of sensory integration improved with age. The evidence for pooling comes from comparison with the predictions of Miller's seminal ‘race model', as well as with a major recent extension of this model and a comparable ‘pooling' (coactivation) model. The findings and analyses can reconcile results from previous audio-visual studies, in which infants showed speed gains exceeding race model predictions in a spatial orienting task (Neil et al., 2006) but children below 7 years did not in speeded reaction time tasks (e.g. Barutchu et al., 2009). Our results provide new evidence for early and sustained abilities to integrate visual and auditory signals for spatial localization from a young age. |
Karly N. Neath-Tavares; Roxane J. Itier Neural processing of fearful and happy facial expressions during emotion-relevant and emotion-irrelevant tasks: A fixation-to-feature approach Journal Article In: Biological Psychology, vol. 119, pp. 122–140, 2016. @article{NeathTavares2016, Research suggests an important role of the eyes and mouth for discriminating facial expressions of emotion. A gaze-contingent procedure was used to test the impact of fixation to facial features on the neural response to fearful, happy and neutral facial expressions in an emotion discrimination (Exp.1) and an oddball detection (Exp.2) task. The N170 was the only eye-sensitive ERP component, and this sensitivity did not vary across facial expressions. In both tasks, compared to neutral faces, responses to happy expressions were seen as early as 100–120 ms occipitally, while responses to fearful expressions started around 150 ms, on or after the N170, at both occipital and lateral-posterior sites. Analyses of scalp topographies revealed different distributions of these two emotion effects across most of the epoch. Emotion processing interacted with fixation location at different times between tasks. Results suggest a role of both the eyes and mouth in the neural processing of fearful expressions and of the mouth in the processing of happy expressions, before 350 ms. |
Sujaya Neupane; Daniel Guitton; Christopher C. Pack Dissociation of forward and convergent remapping in primate visual cortex Journal Article In: Current Biology, vol. 26, no. 12, pp. R491–R492, 2016. @article{Neupane2016, A fundamental concept in neuroscience is the receptive field, the area of space over which a neuron gathers information. Until about 25 years ago, visual receptive fields were thought to be determined entirely by the pattern of retinal inputs, so it was quite surprising to find neurons in primate cortex with receptive fields that changed position every time a saccade was executed [1]. Although this discovery has figured prominently into theories of visual perception, there is still much debate about the nature of the phenomenon: Some studies report forward remapping [1–3], in which receptive fields shift to their postsaccadic locations, and others report convergent remapping, in which receptive fields shift toward the saccade target [4]. These two possibilities can be difficult to distinguish, particularly when the two types of remapping lead to receptive field shifts in similar directions [5], as was the case in virtually all previous experiments. Here we report new data from neurons in primate cortical area V4, where both types of remapping have previously been reported [3,6]. Using an experimental configuration in which forward and convergent remapping would lead to receptive field shifts in opposite directions, we show that forward remapping is the dominant type of receptive field shift in V4. |
Daniel P. Newman; Steven W. Lockley; Gerard M. Loughnane; Ana C. P. Martins; Rafael Abe; Marco T. R. Zoratti; Simon P. Kelly; Megan H. O'Neill; Shantha M. W. Rajaratnam; Redmond G. O'Connell; Mark A. Bellgrove Ocular exposure to blue-enriched light has an asymmetric influence on neural activity and spatial attention Journal Article In: Scientific Reports, vol. 6, pp. 27754, 2016. @article{Newman2016, Brain networks subserving alertness in humans interact with those for spatial attention orienting. We employed blue-enriched light to directly manipulate alertness in healthy volunteers. We show for the first time that prior exposure to higher, relative to lower, intensities of blue-enriched light speeds response times to left, but not right, hemifield visual stimuli, via an asymmetric effect on right-hemisphere parieto-occipital α-power. Our data give rise to the tantalising possibility of light-based interventions for right hemisphere disorders of spatial attention. The mechanisms for alertness in humans interact with those for spatial attention orienting in an intriguing fash-ion 1,2 . For example, the debilitating inattention of left space observed in patients suffering from unilateral spatial neglect subsequent to right-hemisphere damage can be temporarily overcome by phasic alerting tones 3 . Sleep deprivation in healthy participants causes relative left hemifield inattention in the visual domain 4 , while a pro-nounced auditory inattention to left space occurs during drowsy periods prior to sleep onset 5 . Brain imaging work in both neglect patients and neurologically healthy participants suggests that the distribution of attention between the hemifields is balanced by competitive activation between the hemispheres, specifically within a bilaterally represented dorsal network for spatial attention orienting 1,6,7 . Current models propose that this bilateral orienting network interacts with the right-hemisphere-lateralised ventral network subserving non-spatial processes such as alertness 1,2 which may be preferentially innervated by the locus-coeruleus/noradrenergic (LC-NA) system 1,8,9 . Despite demonstrations that manipulations of alertness can transiently shift spatial attention bias, neuro-science has thus far failed to identify non-invasive methods of manipulating alertness that lead to an enduring improvement in attention to left space. One promising avenue for manipulating alertness is offered by recent photobiology studies of light. Although it is recognised that light exerts powerful alerting effects on brain and behaviour, its mechanism of action has only recently been studied. Specifically, recent research has identified a set of intrinsically photosensitive retinal ganglion cells (ipRGCs) which are maximally sensitive to short wavelength (blue) light (~480 nm) and which mediate a light induced alerting signal to the human brain, in a dose dependent manner 10–12 |
Adam C. Snyder; Michael J. Morais; Matthew A. Smith Dynamics of excitatory and inhibitory networks are differentially altered by selective attention Journal Article In: Journal of Neurophysiology, vol. 116, no. 4, pp. 1807–1820, 2016. @article{Snyder2016, Inhibition and excitation form two fundamental modes of neuronal interaction, yet we understand relatively little about their distinct roles in service of perceptual and cognitive processes. We developed a multidimensional waveform analysis to identify fast-spiking (putative inhibitory) and regular-spiking (putative excitatory) neurons in vivo and used this method to analyze how attention affects these two cell classes in visual area V4 of rhesus macaques. We found that putative inhibitory neurons had both greater increases in firing rate and decreases in correlated variability with attention when compared to putative excitatory neurons. Moreover, the time course of attention effects for putative inhibitory neurons more closely tracked the temporal statistics of target probability in our task. Finally, the session-to-session variability in a behavioral measure of attention co-varied with the magnitude of this effect. Together, these results suggest that selective targeting of inhibitory neurons and networks is a critical mechanism for attentional modulation. |
Oleg Solopchuk; Andrea Alamia; Etienne Olivier; Alexandre Zénon Chunking improves symbolic sequence processing and relies on working memory gating mechanisms Journal Article In: Learning and Memory, vol. 23, no. 3, pp. 108–112, 2016. @article{Solopchuk2016, Chunking, namely the grouping of sequence elements in clusters, is ubiquitous during sequence processing, but its impact on performance remains debated. Here, we found that participants who adopted a consistent chunking strategy during symbolic sequence learning showed a greater improvement of their performance and a larger decrease in cognitive workload over time. Stronger reliance on chunking was also associated with higher scores in a WM updating task, suggesting the contribution of WM gating mechanisms to sequence chunking. Altogether, these results indicate that chunking is a cost-saving strategy that enhances effectiveness of symbolic sequence learning. |
Stephen Soncin; Donald C. Brien; Brian C. Coe; Alina Marin; Douglas P. Munoz Contrasting emotion processing and executive functioning in attention-Deficit/hyperactivity disorder and bipolar disorder Journal Article In: Behavioral Neuroscience, vol. 130, no. 5, pp. 531–543, 2016. @article{Soncin2016, Attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BD) are highly comorbid and share executive function and emotion processing deficits, complicating diagnoses despite distinct clinical features. We compared performance on an oculomotor task that assessed these processes to capture subtle differences between ADHD and BD. The interaction between emotion processing and executive functioning may be informative because, although these processes overlap anatomically, certain regions that are compromised in each network are different in ADHD and BD. Adults, aged 18-62, with ADHD ( = 22), BD ( = 20), and healthy controls ( = 21) performed an interleaved pro- and antisaccade task (looking toward vs. looking away from a visual target, respectively). Task irrelevant emotional faces (fear, happy, sad, neutral) were presented on a subset of trials either before or with the target. The ADHD group made more direction errors (looked in the wrong direction) than controls. Presentation of negatively valenced (fear, sad) and ambiguous (neutral) emotional faces increased saccadic reaction time in BD only compared to controls, whereas longer presentation of sad faces modestly increased group differences. The antisaccade task differentiated ADHD from controls. Emotional processing further impaired processing speed in BD. We propose that the dorsolateral prefrontal cortex is critical in both processing systems, but the inhibitory signal this region generates is impacted by dysfunction in the emotion processing network, possibly at the orbitofrontal cortex, in BD. These results suggest there are differences in how emotion processing and executive functioning interact, which could be utilized to improve diagnostic specificity. |
David Souto; Karl R. Gegenfurtner; Alexander C. Schütz Saccade adaptation and visual uncertainty Journal Article In: Frontiers in Human Neuroscience, vol. 10, pp. 227, 2016. @article{Souto2016, Visual uncertainty may affect saccade adaptation in two complementary ways. First, an ideal adaptor should take into account the reliability of visual information for determining the amount of correction, predicting that increasing visual uncertainty should decrease adaptation rates. We tested this by comparing observers' direction discrimination and adaptation rates in an intra-saccadic-step paradigm. Second, clearly visible target steps may generate a slower adaptation rate since the error can be attributed to an external cause, instead of an internal change in the visuo-motor mapping that needs to be compensated. We tested this prediction by measuring saccade adaptation to different step sizes. Most remarkably, we found little correlation between estimates of visual uncertainty and adaptation rates and no slower adaptation rates with more visible step sizes. Additionally, we show that for low contrast targets backward steps are perceived as stationary after the saccade, but that adaptation rates are independent of contrast. We suggest that the saccadic system uses different position signals for adapting dysmetric saccades and for generating a trans-saccadic stable visual percept, explaining that saccade adaptation is found to be independent of visual uncertainty. |
Eelke Spaak; Yvonne Fonken; Ole Jensen; Floris P. Lange The neural mechanisms of prediction in visual search Journal Article In: Cerebral Cortex, vol. 26, no. 11, pp. 4327–4336, 2016. @article{Spaak2016, 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. |
Anja Sperlich; Johannes Meixner; Jochen Laubrock Development of the perceptual span in reading: A longitudinal study Journal Article In: Journal of Experimental Child Psychology, vol. 146, pp. 181–201, 2016. @article{Sperlich2016, The perceptual span is a standard measure of parafoveal processing, which is considered highly important for efficient reading. Is the perceptual span a stable indicator of reading performance? What drives its development? Do initially slower and faster readers converge or diverge over development? Here we present the first longitudinal data on the development of the perceptual span in elementary school children. Using the moving window technique, eye movements of 127 German children in three age groups (Grades 1, 2, and 3 in Year 1) were recorded at two time points (T1 and T2) 1 year apart. Introducing a new measure of the perceptual span, nonlinear mixed-effects modeling was used to separate window size effects from asymptotic reading performance. Cross-sectional differences were well replicated longitudinally. Asymptotic reading rate increased monotonously with grade, but in a decelerating fashion. A significant change in the perceptual span was observed only between Grades 2 and 3. Together with results from a cross-lagged panel model, this suggests that the perceptual span increases as a consequence of relatively well-established word reading. Stabilities of observed and predicted reading rates were high after Grade 1, whereas the perceptual span was only moderately stable for all grades. Comparing faster and slower readers as assessed at T1, in general, a pattern of stable between-group differences emerged rather than a compensatory pattern; second and third graders even showed a Matthew effect in reading rate and the perceptual span, respectively. |
Sara Spotorno; Guillaume S. Masson; Anna Montagnini Fixational saccades during grating detection and discrimination Journal Article In: Vision Research, vol. 118, pp. 105–118, 2016. @article{Spotorno2016, We investigated the patterns of fixational saccades in human observers performing two classical perceptual tasks: grating detection and discrimination. First, participants were asked to detect a vertical or tilted grating with one of three spatial frequencies and one of four luminance contrast levels. In the second experiment, participants had to discriminate the spatial frequency of two supra-threshold gratings. The gratings were always embedded in additive, high- or low-contrast pink noise. We observed that the patterns of fixational saccades were highly idiosyncratic among participants. Moreover, during the grating detection task, the amplitude and the number of saccades were inversely correlated with stimulus visibility. We did not find a systematic relationship between saccade parameters and grating frequency, apart from a slight decrease of saccade amplitude during grating discrimination with higher spatial frequencies. No consistent changes in the number and amplitude of fixational saccades with performance accuracy were reported. Surprisingly, during grating detection, saccade number and amplitude were similar in grating-with-noise and noise-only displays. Grating orientation did not affect substantially saccade direction in either task. The results challenge the idea that, when analyzing low-level spatial properties of visual stimuli, fixational saccades can be adapted in order to extract task-relevant information optimally. Rather, saccadic patterns seem to be overall modulated by task context, stimulus visibility and individual variability. |
William W. Sprague; Emily A. Cooper; Sylvain Reissier; Baladitya Yellapragada; Martin S. Banks The natural statistics of blur Journal Article In: Journal of Vision, vol. 16, no. 10, pp. 1–27, 2016. @article{Sprague2016, Blur from defocus can be both useful and detrimental for visual perception: It can be useful as a source of depth information and detrimental because it degrades image quality. We examined these aspects of blur by measuring the natural statistics of defocus blur across the visual field. Participants wore an eye-and-scene tracker that measured gaze direction, pupil diameter, and scene distances as they perfomed everyday tasks. We found that blur magnitude increases with increasing eccentricity. There is a vertical gradient in the distances that generate defocus blur: Blur below the fovea is generally due to scene points nearer than fixation; blur above the fovea is mostly due to points farther than fixation. There is no systematic horizontal gradient. Large blurs are generally caused by points farther rather than nearer than fixation. Consistent with the statistics, participants in a perceptual experiment perceived vertical blur gradients as slanted top-back whereas horizontal gradients were perceived equally as left-back and right-back. The tendency for people to see sharp as near and blurred as far is also consistent with the observed statistics. We calculated how many observations will be perceived as unsharp and found that perceptible blur is rare. Finally, we found that eye shape in ground-dwelling animals conforms to that required to put likely distances in best focus. |
Eyal Seidemann; Yuzhi Chen; Yoon Bai; Spencer C. Chen; Preeti Mehta; Bridget L. Kajs; Wilson S. Geisler; Boris V. Zemelman Calcium imaging with genetically encoded indicators in behaving primates Journal Article In: eLife, vol. 5, pp. 1–19, 2016. @article{Seidemann2016, Understanding the neural basis of behaviour requires studying brain activity in behaving subjects using complementary techniques that measure neural responses at multiple spatial scales, and developing computational tools for understanding the mapping between these measurements. Here we report the first results of widefield imaging of genetically encoded calcium indicator (GCaMP6f) signals from V1 of behaving macaques. This technique provides a robust readout of visual population responses at the columnar scale over multiple mm(2) and over several months. To determine the quantitative relation between the widefield GCaMP signals and the locally pooled spiking activity, we developed a computational model that sums the responses of V1 neurons characterized by prior single unit measurements. The measured tuning properties of the GCaMP signals to stimulus contrast, orientation and spatial position closely match the predictions of the model, suggesting that widefield GCaMP signals are linearly related to the summed local spiking activity. |
Matthew W. Self; Judith C. Peters; Jessy K. Possel; Joel Reithler; Rainer Goebel; Peterjan Ris; Danique Jeurissen; Leila Reddy; Steven Claus; Johannes C. Baayen; Pieter R. Roelfsema The effects of context and attention on spiking activity in human early visual cortex Journal Article In: PLoS Biology, vol. 14, no. 3, pp. e1002420, 2016. @article{Self2016, Here we report the first quantitative analysis of spiking activity in human early visual cortex. We recorded multi-unit activity from two electrodes in area V2/V3 of a human patient implanted with depth electrodes as part of her treatment for epilepsy. We observed well-localized multi-unit receptive fields with tunings for contrast, orientation, spatial frequency, and size, similar to those reported in the macaque. We also observed pronounced gamma oscillations in the local-field potential that could be used to estimate the underlying spiking response properties. Spiking responses were modulated by visual context and attention. We observed orientation-tuned surround suppression: responses were suppressed by image regions with a uniform orientation and enhanced by orientation contrast. Additionally, responses were enhanced on regions that perceptually segregated from the background, indicating that neurons in the human visual cortex are sensitive to figure-ground structure. Spiking responses were also modulated by object-based attention. When the patient mentally traced a curve through the neurons' receptive fields, the accompanying shift of attention enhanced neuronal activity. These results demonstrate that the tuning properties of cells in the human early visual cortex are similar to those in the macaque and that responses can be modulated by both contextual factors and behavioral relevance. Our results, therefore, imply that the macaque visual system is an excellent model for the human visual cortex. |
Gözde Şentürk; Adam S. Greenberg; Taosheng Liu Saccade latency indexes exogenous and endogenous object-based attention Journal Article In: Attention, Perception, and Psychophysics, vol. 78, no. 7, pp. 1998–2013, 2016. @article{Sentuerk2016, Classic studies of object-based attention have utilized keypress responses as the main dependent measure. However, people typically make saccades to fixate important objects. Recent work has shown that attention may act differently when it is deployed covertly versus in advance of a saccade. We further investigated the link between saccades and attention by examining whether object-based effects can be observed for saccades. We adapted the classical double-rectangle cueing paradigm of Egly, Driver, and Rafal (1994), and measured both the first saccade latency and the keypress reaction time (RT) to a target that appeared at the end of one of the two rectangles. Our results showed that saccade latencies exhibited higher sensitivity than did RTs for detecting effects of attention. We also assessed the generality of the attention effects by testing three types of cues: hybrid (predictive and peripheral), exogenous (nonpredictive and peripheral), and endogenous (predictive and central). We found that both RTs and saccade latencies exhibited effects of both space-based and object-based attentional selection. However, saccade latencies showed a more robust attentional modulation than RTs. For the exogenous cues, we observed a spatial inhibition of return along with an object-based effect, implying that object-based attention is independent of space-based attention. Overall, our results revealed an oculomotor correlate of object-based attention, suggesting that, in addition to spatial priority, object-level priority also affects saccade planning. |
Aasef G. Shaikh; Jorge Otero-Millan; Priyanka Kumar; Fatema F. Ghasia Abnormal fixational eye movements in amblyopia Journal Article In: PLoS ONE, vol. 11, no. 3, pp. e0149953, 2016. @article{Shaikh2016, PURPOSE: Fixational saccades shift the foveal image to counteract visual fading related to neural adaptation. Drifts are slow eye movements between two adjacent fixational saccades. We quantified fixational saccades and asked whether their changes could be attributed to pathologic drifts seen in amblyopia, one of the most common causes of blindness in childhood. METHODS: Thirty-six pediatric subjects with varying severity of amblyopia and eleven healthy age-matched controls held their gaze on a visual target. Eye movements were measured with high-resolution video-oculography during fellow eye-viewing and amblyopic eye-viewing conditions. Fixational saccades and drifts were analyzed in the amblyopic and fellow eye and compared with controls. RESULTS: We found an increase in the amplitude with decreased frequency of fixational saccades in children with amblyopia. These alterations in fixational eye movements correlated with the severity of their amblyopia. There was also an increase in eye position variance during drifts in amblyopes. There was no correlation between the eye position variance or the eye velocity during ocular drifts and the amplitude of subsequent fixational saccade. Our findings suggest that abnormalities in fixational saccades in amblyopia are independent of the ocular drift. DISCUSSION: This investigation of amblyopia in pediatric age group quantitatively characterizes the fixation instability. Impaired properties of fixational saccades could be the consequence of abnormal processing and reorganization of the visual system in amblyopia. Paucity in the visual feedback during amblyopic eye-viewing condition can attribute to the increased eye position variance and drift velocity. |
Naveed A. Sheikh; Debra Titone The embodiment of emotional words in a second language: An eye-movement study Journal Article In: Cognition and Emotion, vol. 30, no. 3, pp. 488–500, 2016. @article{Sheikh2016, The hypothesis that word representations are emotionally impoverished in a second language (L2) has variable support. However, this hypothesis has only been tested using tasks that present words in isolation or that require laboratory-specific decisions. Here, we recorded eye movements for 34 bilinguals who read sentences in their L2 with no goal other than comprehension, and compared them to 43 first language readers taken from our prior study. Positive words were read more quickly than neutral words in the L2 across first-pass reading time measures. However, this emotional advantage was absent for negative words for the earliest measures. Moreover, negative words but not positive words were influenced by concreteness, frequency and L2 proficiency in a manner similar to neutral words. Taken together, the findings suggest that only negative words are at risk of emotional disembodiment during L2 reading, perhaps because a positivity bias in L2 experiences ensures that positive words are emotionally grounded. |
Bin Shen; Meng-Chun Chiu; Shuo-Heng Li; Guo-Joe Huang; Ling-Jun Liu; Ming-Chou Ho Attentional bias to betel quid cues: An eye tracking study Journal Article In: Psychology of Addictive Behaviors, vol. 30, no. 6, pp. 705–711, 2016. @article{Shen2016, The World Health Organization regards betel quid as a human carcinogen, and DSM-IV and ICD-10 dependence symptoms may develop with heavy use. This study, conducted in central Taiwan, investigated whether betel quid chewers can exhibit overt orienting to selectively respond to the betel quid cues. Twenty-four male chewers' and 23 male nonchewers' eye movements to betel-quid-related pictures and matched pictures were assessed during a visual probe task. The eye movement index showed that betel quid chewers were more likely to initially direct their gaze to the betel quid cues, t(23) = 3.70, p < .01 |
Wei Shen; Qingqing Qu; Xingshan Li In: Attention, Perception, and Psychophysics, vol. 78, no. 5, pp. 1267–1284, 2016. @article{Shen2016a, In the present study, we investigated whether the activation of semantic information during spoken word recognition can mediate visual attention's deployment to printed Chinese words. We used a visual-world paradigm with printed words, in which participants listened to a spoken target word embedded in a neutral spoken sentence while looking at a visual display of printed words. We examined whether a semantic competitor effect could be observed in the printed-word version of the visual-world paradigm. In Experiment 1, the relationship between the spoken target words and the printed words was manipulated so that they were semantically related (a semantic competitor), phonologically related (a phonological competitor), or unrelated (distractors). We found that the probability of fixations on semantic competitors was significantly higher than that of fixations on the distractors. In Experiment 2, the orthographic similarity between the spoken target words and their semantic competitors was manipulated to further examine whether the semantic competitor effect was modulated by orthographic similarity. We found significant semantic competitor effects regardless of orthographic similarity. Our study not only reveals that semantic information can affect visual attention, it also provides important new insights into the methodology employed to investigate the semantic processing of spoken words during spoken word recognition using the printed-word version of the visual-world paradigm. |
Heather Sheridan; Erik D. Reichle; Eyal M. Reingold Why does removing inter-word spaces produce reading deficits? The role of parafoveal processing Journal Article In: Psychonomic Bulletin & Review, vol. 23, no. 5, pp. 1543–1552, 2016. @article{Sheridan2016, To examine the role of inter-word spaces during reading, we used a gaze-contingent boundary paradigm to manipulate parafoveal preview (i.e., valid vs. invalid preview) in a normal text condition that contained spaces (e.g., "John decided to sell the table") and in an unsegmented text condition that contained random numbers instead of spaces (e.g.,"John4decided8to5sell9the7table"). Preview effects on mean first-fixation durations were larger for normal than unsegmented text conditions, and survival analyses revealed a delay in the onset of both preview validity and word-frequency effects on first-fixation durations for unsegmented relative to normal text. Taken together with simulations that were conducted using the E-Z Reader model, the present findings indicated that unsegmented text deficits reflect disruptions to both parafoveal processing and lexical processing. We discuss the implications of our results for models of eye-movement control. |
Hanlin Tang; Jedediah M. Singer; Matias J. Ison; Gnel Pivazyan; Melissa Romaine; Rosa Frias; Elizabeth Meller; Adrianna Boulin; James Carroll; Victoria Perron; Sarah Dowcett; Marlise Arellano; Gabriel Kreiman Predicting episodic memory formation for movie events Journal Article In: Scientific Reports, vol. 6, pp. 30175, 2016. @article{Tang2016, Episodic memories are long lasting and full of detail, yet imperfect and malleable. We quantitatively evaluated recollection of short audiovisual segments from movies as a proxy to real-life memory formation in 161 subjects at 15minutes up to a year after encoding. Memories were reproducible within and across individuals, showed the typical decay with time elapsed between encoding and testing, were fallible yet accurate, and were insensitive to low-level stimulus manipulations but sensitive to high-level stimulus properties. Remarkably, memorability was also high for single movie frames, even one year post-encoding. To evaluate what determines the efficacy of long-term memory formation, we developed an extensive set of content annotations that included actions, emotional valence, visual cues and auditory cues. These annotations enabled us to document the content properties that showed a stronger correlation with recognition memory and to build a machine-learning computational model that accounted for episodic memory formation in single events for group averages and individual subjects with an accuracy of up to 80%. These results provide initial steps towards the development of a quantitative computational theory capable of explaining the subjective filtering steps that lead to how humans learn and consolidate memories. |
A. Caglar Tas; Steven J. Luck; Andrew Hollingworth The relationship between visual attention and visual working memory encoding: A dissociation between covert and overt orienting Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 48, no. 8, pp. 1121–1138, 2016. @article{Tas2016, There is substantial debate over whether visual working memory (VWM) and visual attention constitute a single system for the selection of task-relevant perceptual information or whether they are distinct systems that can be dissociated when their representational demands diverge. In the present study, we focused on the relationship between visual attention and the encoding of objects into VWM. Participants performed a color change-detection task. During the retention interval, a secondary object, irrelevant to the memory task, was presented. Participants were instructed either to execute an overt shift of gaze to this object (Experiments 1–3) or to attend it covertly (Experiments 4 and 5). Our goal was to determine whether these overt and covert shifts of attention disrupted the information held in VWM. We hypothesized that saccades, which typically introduce a memorial demand to bridge perceptual disrup- tion, would lead to automatic encoding of the secondary object. However, purely covert shifts of attention, which introduce no such demand, would not result in automatic memory encoding. The results supported these predictions. Saccades to the secondary object produced substantial interference with VWM performance, but covert shifts of attention to this object produced no interference with VWM performance. These results challenge prevailing theories that consider attention and VWM to reflect a common mechanism. In addition, they indicate that the relationship between attention and VWM is dependent on the memorial demands of the orienting behavior. |
Jessica Taubert; Valerie Goffaux; Goedele Van Belle; Wim Vanduffel; Rufin Vogels The impact of orientation filtering on face-selective neurons in monkey inferior temporal cortex Journal Article In: Scientific Reports, vol. 6, pp. 21189, 2016. @article{Taubert2016, Faces convey complex social signals to primates. These signals are tolerant of some image transformations (e.g. changes in size) but not others (e.g. picture-plane rotation). By filtering face stimuli for orientation content, studies of human behavior and brain responses have shown that face processing is tuned to selective orientation ranges. In the present study, for the first time, we recorded the responses of face-selective neurons in monkey inferior temporal (IT) cortex to intact and scrambled faces that were filtered to selectively preserve horizontal or vertical information. Guided by functional maps, we recorded neurons in the lateral middle patch (ML), the lateral anterior patch (AL), and an additional region located outside of the functionally defined face-patches (CONTROL). We found that neurons in ML preferred horizontal-passed faces over their vertical-passed counterparts. Neurons in AL, however, had a preference for vertical-passed faces, while neurons in CONTROL had no systematic preference. Importantly, orientation filtering did not modulate the firing rate of neurons to phase-scrambled face stimuli in any recording region. Together these results suggest that face-selective neurons found in the face-selective patches are differentially tuned to orientation content, with horizontal tuning in area ML and vertical tuning in area AL. |
Jessica Nelson Taylor; Charles A. Perfetti Eye movements reveal readers' lexical quality and reading experience Journal Article In: Reading and Writing, vol. 29, no. 6, pp. 1069–1103, 2016. @article{Taylor2016, Two experiments demonstrate that individual differences among normal adult readers, including lexical quality, are expressed in silent reading at the word level. In the first of two studies we identified major dimensions of variability among college readers and among words using factor analysis. We then examined the effects of these dimensions of variability on eye movements during paragraph reading. More experienced readers (who also were higher in reading speed) read words more quickly, especially less frequent words, while readers with higher lexical knowledge showed shorter early fixations, especially for more frequent words. These results suggest that individual differences in reading may reflect differences in the quality of lexical representations and in reading experience, which is a source of lexical quality. In a second study, we controlled the lexical knowledge readers obtained from new words through a training paradigm that varied exposure to a word's orthographic, phonological, and meaning constituents. Training exposure to orthographic and phonological constituents affected first pass reading measures, and phonological and meaning training affected second pass measures. Incomplete knowledge of word components slowed first pass reading times, com- pared to both more complete knowledge and no knowledge. Training effects were mediated by individual differences, pointing to lexical quality and reading experi- ence—which, combined reflect reading expertise—as important in word reading as part of text reading. |
Yasuo Terao; Hideki Fukuda; Shinnichi Tokushuge; Yoshiko Nomura; Ritsuko Hanajima; Yoshikazu Ugawa Saccade abnormalities associated with focal cerebral lesions – How cortical and basal ganglia commands shape saccades in humans Journal Article In: Clinical Neurophysiology, vol. 127, no. 8, pp. 2953–2967, 2016. @article{Terao2016, Objective: To study saccade abnormalities associated with focal cerebral lesions, including the cerebral cortex and basal ganglia (BG). Methods: We studied the latency and amplitude of reflexive and voluntary saccades in 37 patients with focal lesions of the frontal and parietal cortices and BG (caudate and putamen), and 51 age-matched controls, along with the ability to inhibit unwanted reflexive saccades. Results: Latencies of reflexive saccades were prolonged in patients with parietal lesions involving the parietal eye field (PEF), whereas their amplitude was decreased with parietal or putaminal lesions. In contrast, latency of voluntary saccades was prolonged and their success rate reduced with frontal lesions including the frontal eye field (FEF) or its outflow tract as well as the dorsolateral/medial prefrontal cortex, and caudate lesions, whereas their amplitude was decreased with parietal lesions. Inhibitory control of reflexive saccades was impaired with frontal, caudate and, less prominently, parietal lesions. Conclusions: PEF is important in triggering reflexive saccades, also determining their amplitude. Whereas FEF and the caudate emit commands for initiating voluntary saccades, their amplitude is mainly determined by PEF. Commands not only from FEF and dorsolateral/medial prefrontal cortex but also from the caudate and PEF serve to inhibit unnecessary reflexive saccades. Significance: The findings suggested how cortical and BG commands shape reflexive and voluntary saccades in humans. |
Louis Thibault; Ronald Van Den Berg; Patrick Cavanagh; Claire Sergent Retrospective attention gates discrete conscious access to past sensory stimuli Journal Article In: PLoS ONE, vol. 11, no. 2, pp. e0148504, 2016. @article{Thibault2016, Cueing attention after the disappearance of visual stimuli biases which items will be remembered best. This observation has historically been attributed to the influence of attention on memory as opposed to subjective visual experience. We recently challenged this view by showing that cueing attention after the stimulus can improve the perception of a single Gabor patch at threshold levels of contrast. Here, we test whether this retro-perception actually increases the frequency of consciously perceiving the stimulus, or simply allows for a more precise recall of its features. We used retro-cues in an orientation-matching task and performed mixture-model analysis to independently estimate the proportion of guesses and the precision of non-guess responses. We find that the improvements in performance conferred by retrospective attention are overwhelmingly determined by a reduction in the proportion of guesses, providing strong evidence that attracting attention to the target's location after its disappearance increases the likelihood of perceiving it consciously. |
Vijay Vitthal Thitme; Akanksha Varghese Image retrieval using vector of locally aggregated descriptors Journal Article In: International Journal of Advance Research in Computer Science and Management Studies, vol. 4, no. 2, pp. 97–104, 2016. @article{Thitme2016, Partial duplicate image retrieval is very powerful and important task in the real world applications such as landmark search, copyright protection, fake image identification. In the internet applications users continuously upload images which may be partially duplicate images on the domains like social sites orkut, facebook, and related applications etc. The partial image is nothing but segment of whole image, and the various methods of transformations are scaling, resolution, illumination, rotation and viewpoint. This method is considered as of much more valuable by different real world aspects and has motivated towards this study. The method of retrieving images which is based on the object methods generally uses the whole image as the query image. In object based image retrieval methods usually use the whole image as the query. This method is compared with text system by using the bag of visual words (BOV) Generally there may be lots of noise on the images so it is impossible to perform operations on large scale dataset of images. This approach is not much more used because no any spatial data is used to retrieve the efficient images.The art of image retrieval methods represent image with a large dimensional vector of visual words by making quantization of local features, such as Scale Invariant Feature Transform, solely on the descriptor space. Quantization of the Local features to visual words are done firstly in descriptor space and then in orientation space. Local Self-Similarity Descriptor (LSSD) value is used which is used to captures the internal geometric layouts in the local text self-similar regions near interest points. |
Kathleen Thomaes; Iris M. Engelhard; Marit Sijbrandij; Danielle C. Cath; Odile A. Heuvel Degrading traumatic memories with eye movements: A pilot functional MRI study in PTSD Journal Article In: European Journal of Psychotraumatology, vol. 7, no. 1, pp. 1–10, 2016. @article{Thomaes2016, 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. |
Paul M. J. Thomas; Lily Fitz Gibbon; Jane E. Raymond Value conditioning modulates visual working memory processes Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 42, no. 1, pp. 6–10, 2016. @article{Thomas2016, Learning allows the value of motivationally salient events to become associated with stimuli that predict those events. Here, we asked whether value associations could facilitate visual working memory (WM), and whether such effects would be valence dependent. Our experiment was specifically designed to isolate value-based effects on WM from value-based effects on selective attention that might be expected to bias encoding. In a simple associative learning task, participants learned to associate the color of tinted faces with gaining or losing money or neither. Tinted faces then served as memoranda in a face identity WM task for which previously learned color associations were irrelevant and no monetary outcomes were forthcoming. Memory was best for faces with gain-associated tints, poorest for faces with loss-associated tints, and average for faces with no-outcome-associated tints. Value associated with 1 item in the WM array did not modulate memory for other items in the array. Eye movements when studying faces did not depend on the valence of previously learned color associations, arguing against value-based biases being due to differential encoding. This valence-sensitive value-conditioning effect on WM appears to result from modulation of WM maintenance processes. |
Xiaoguang Tian; Masatoshi Yoshida; Ziad M. Hafed A microsaccadic account of attentional capture and inhibition of return in Posner cueing Journal Article In: Frontiers in Systems Neuroscience, vol. 10, pp. 23, 2016. @article{Tian2016, Microsaccades exhibit systematic oscillations in direction after spatial cueing, and these oscillations correlate with facilitatory and inhibitory changes in behavioral performance in the same tasks. However, independent of cueing, facilitatory and inhibitory changes in visual sensitivity also arise pre-microsaccadically. Given such pre-microsaccadic modulation, an imperative question to ask becomes: how much of task performance in spatial cueing may be attributable to these peri-movement changes in visual sensitivity? To investigate this question, we adopted a theoretical approach. We developed a minimalist model in which: (1) microsaccades are repetitively generated using a rise-to-threshold mechanism, and (2) pre-microsaccadic target onset is associated with direction-dependent modulation of visual sensitivity, as found experimentally. We asked whether such a model alone is sufficient to account for performance dynamics in spatial cueing. Our model not only explained fine-scale microsaccade frequency and direction modulations after spatial cueing, but it also generated classic facilitatory (i.e., attentional capture) and inhibitory [i.e., inhibition of return (IOR)] effects of the cue on behavioral performance. According to the model, cues reflexively reset the oculomotor system, which unmasks oscillatory processes underlying microsaccade generation; once these oscillatory processes are unmasked, "attentional capture" and "IOR" become direct outcomes of pre-microsaccadic enhancement or suppression, respectively. Interestingly, our model predicted that facilitatory and inhibitory effects on behavior should appear as a function of target onset relative to microsaccades even without prior cues. We experimentally validated this prediction for both saccadic and manual responses. We also established a potential causal mechanism for the microsaccadic oscillatory processes hypothesized by our model. We used retinal-image stabilization to experimentally control instantaneous foveal motor error during the presentation of peripheral cues, and we found that post-cue microsaccadic oscillations were severely disrupted. This suggests that microsaccades in spatial cueing tasks reflect active oculomotor correction of foveal motor error, rather than presumed oscillatory covert attentional processes. Taken together, our results demonstrate that peri-microsaccadic changes in vision can go a long way in accounting for some classic behavioral phenomena. |
Shin-ichi Tokushige; Yasuo Terao; Shun-ichi Matsuda; Satomi Inomata-Terada; Takahiro Shimizu; Nobuyuki Tanaka; Masashi Hamada; Akihiro Yugeta; Ritsuko Hanajima; Harushi Mori; Shoji Tsuji; Yoshikazu Ugawa Motor neuron disease with saccadic abnormalities similar to progressive supranuclear palsy Journal Article In: Neurology and Clinical Neuroscience, vol. 4, pp. 146–152, 2016. @article{Tokushige2016, Background: In recent years, a variety of clinical types of amyotrophic lateral sclerosis have come to be recognized. As some patients present with oculomotor abnormalities both clinically and pathologically, the progressive supranuclear palsy variant of amyotrophic lateral sclerosis has been proposed. Aim: To describe atypical cases of motor neuron disease with abnormal extraocular movements mimicking progressive supranuclear palsy. Methods: We present three motor neuron disease patients with slow saccades, who were aged 57, 63 and 62 years. Neurological examinations found vertical gaze palsy in two patients. The two patients who presented extrapyramidal signs were regarded as motor neuron disease with parkinsonism, whereas the other was diagnosed with amyotrophic lateral sclerosis. Their saccades were investigated by visually-guided saccade and memory-guided saccade tasks, and were compared with those of 14 age-matched normal participants (60.3 +/- 1.9 years). Results: In all these patients, the visually-guided saccade latencies were significantly prolonged compared with normal participants, whereas the memory-guided saccade latencies were not. The velocity and amplitude of saccades of the patients were significantly reduced in visually-guided saccade and memory-guided saccade in comparison with normal participants. Conclusion: The patterns of saccadic abnormalities in the patients were similar to those of progressive supranuclear palsy patients, suggesting that some patients with motor neuron disease show saccade abnormalities similar to those of progressive supranuclear palsy patients from the clinical and physiological perspective. Motor neuron disease with slow saccades and parkinsonism, as reported here, suggest the existence of progressive supranuclear palsy-variant amyotrophic lateral sclerosis. |
Jianliang Tong; Jun Maruta; Kristin J. Heaton; Alexis L. Maule; Umesh Rajashekar; Lisa A. Spielman; Jamshid Ghajar Degradation of binocular coordination during sleep deprivation Journal Article In: Frontiers in Neurology, vol. 7, pp. 90, 2016. @article{Tong2016, To aid a clear and unified visual perception while tracking a moving target, both eyes must be coordinated, so the image of the target falls on approximately corresponding areas of the fovea of each eye. The movements of the two eyes are decoupled during sleep, suggesting a role of arousal in regulating binocular coordination. While the absence of visual input during sleep may also contribute to binocular decoupling, sleepiness is a state of reduced arousal that still allows for visual input, providing a context within which the role of arousal in binocular coordination can be studied. We examined the effects of sleep deprivation on binocular coordination using a test paradigm that we previously showed to be sensitive to sleep deprivation. We quantified binocular coordination with the SD of the distance between left and right gaze positions on the screen. We also quantified the stability of conjugate gaze on the target, i.e., gaze-target synchronization, with the SD of the distance between the binocular average gaze and the target. Sleep deprivation degraded the stability of both binocular coordination and gaze-target synchronization, but between these two forms of gaze control the horizontal and vertical components were affected differently, suggesting that disconjugate and conjugate eye movements are under different regulation of attentional arousal. The prominent association found between sleep deprivation and degradation of binocular coordination in the horizontal direction may be used for a fit-for-duty assessment. |
Mark Torrance; Roger Johansson; Victoria Johansson; Åsa Wengelin Reading during the composition of multi-sentence texts: An eye-movement study Journal Article In: Psychological Research, vol. 80, no. 5, pp. 729–743, 2016. @article{Torrance2016, Writers composing multi-sentence texts have immediate access to a visual representation of what they have written. Little is known about the detail of writers' eye movements within this text during production. We describe two experiments in which competent adult writ- ers' eye movements were tracked while performing short expository writing tasks. These are contrasted with condi- tions in which participants read and evaluated researcher- provided texts. Writers spent a mean of around 13 % of their time looking back into their text. Initiation of these look-back sequences was strongly predicted by linguisti- cally important boundaries in their ongoing production (e.g., writers were much more likely to look back imme- diately prior to starting a new sentence). 36 %of look-back sequences were associated with sustained reading and the remainder with less patterned forward and backward sac- cades between words (‘‘hopping''). Fixation and gaze durations and the presence of word-length effects sug- gested lexical processing of fixated words in both reading and hopping sequences. Word frequency effects were not present when writers read their own text. Findings demonstrate the technical possibility and potential value of examining writers' fixations within their just-written text. We suggest that these fixations do not serve solely, or even primarily, in monitoring for error, but play an important role in planning ongoing production. |
Matteo Toscani; Sunčica Zdravković; Karl R. Gegenfurtner Lightness perception for surfaces moving through different illumination levels Journal Article In: Journal of Vision, vol. 16, no. 15, pp. 1–18, 2016. @article{Toscani2016, Lightness perception has mainly been studied with static scenes so far. This study presents four experiments investigating lightness perception under dynamic illumination conditions. We asked participants for lightness matches of a virtual three-dimensional target moving through a light field while their eye movements were recorded. We found that the target appeared differently, depending on the direction of motion in the light field and its precise position in the light field. Lightness was also strongly affected by the choice of fixation positions with the spatiotemporal image sequence. Overall, lightness constancy was improved when observers could freely view the object, over when they were forced to fixate certain regions. Our results show that dynamic scenes and nonuniform light fields are particularly challenging for our visual system. Eye movements in such scenarios are chosen to improve lightness constancy. |
Annie Tran; James E. Hoffman Visual attention is required for multiple object tracking Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 42, no. 12, pp. 2103–2114, 2016. @article{Tran2016, In the multiple object tracking task, participants attempt to keep track of a moving set of target objects embedded in an identical set of moving distractors. Depending on several display parameters, observers are usually only able to accurately track 3 to 4 objects. Various proposals attribute this limit to a fixed number of discrete indexes (Pylyshyn, 1989), limits in visual attention (Cavanagh & Alvarez, 2005), or “architectural limits” in visual cortical areas (Franconeri, 2013). The present set of experiments examined the specific role of visual attention in tracking using a dual-task methodology in which participants tracked objects while identifying letter probes appearing on the tracked objects and distractors. As predicted by the visual attention model, probe identification was faster and/or more accurate when probes appeared on tracked objects. This was the case even when probes were more than twice as likely to appear on distractors suggesting that some minimum amount of attention is required to maintain accurate tracking performance. When the need to protect tracking accuracy was relaxed, participants were able to allocate more attention to distractors when probes were likely to appear there but only at the expense of large reductions in tracking accuracy. A final experiment showed that people attend to tracked objects even when letters appearing on them are task-irrelevant, suggesting that allocation of attention to tracked objects is an obligatory process. These results support the claim that visual attention is required for tracking objects. |
Annie Tremblay; Mirjam Broersma; Caitlin E. Coughlin; Jiyoun Choi Effects of the native language on the learning of fundamental frequency in second-language speech segmentation Journal Article In: Frontiers in Psychology, vol. 7, pp. 985, 2016. @article{Tremblay2016, This study investigates whether the learning of prosodic cues to word boundaries in speech segmentation is more difficult if the native and second/foreign languages (L1 and L2) have similar (though non-identical) prosodies than if they have markedly different prosodies (Prosodic-Learning Interference Hypothesis). It does so by comparing French, Korean, and English listeners' use of fundamental-frequency (F0) rise as a cue to word-final boundaries in French. F0 rise signals phrase-final boundaries in French and Korean but word-initial boundaries in English. Korean-speaking and English-speaking L2 learners of French, who were matched in their French proficiency and French experience, and native French listeners completed a visual-world eye-tracking experiment in which they recognized words whose final boundary was or was not cued by an increase in F0. The results showed that Korean listeners had greater difficulty using F0 rise as a cue to word-final boundaries in French than French and English listeners. This suggests that L1-L2 prosodic similarity can make the learning of an L2 segmentation cue difficult, in line with the proposed Prosodic-Learning Interference Hypothesis. We consider mechanisms that may underlie this difficulty and discuss the implications of our findings for understanding listeners' phonological encoding of L2 words. |
Johanne Tromp; Peter Hagoort; Antje S. Meyer Pupillometry reveals increased pupil size during indirect request comprehension Journal Article In: Quarterly Journal of Experimental Psychology, vol. 69, no. 6, pp. 1093–1108, 2016. @article{Tromp2016, Fluctuations in pupil size have been shown to reflect variations in processing demands during lexical and syntactic processing in language comprehension. An issue that has not received attention is whether pupil size also varies due to pragmatic manipulations. In two pupillometry experiments, we investigated whether pupil diameter was sensitive to increased processing demands as a result of comprehending an indirect request versus a direct statement. Adult participants were presented with 120 picture-sentence combinations that could be interpreted either as an indirect request (a picture of a window with the sentence "it's very hot here") or as a statement (a picture of a window with the sentence "it's very nice here"). Based on the hypothesis that understanding indirect utterances requires additional inferences to be made on the part of the listener, we predicted a larger pupil diameter for indirect requests than statements. The results of both experiments are consistent with this expectation. We suggest that the increase in pupil size reflects additional processing demands for the comprehension of indirect requests as compared to statements. This research demonstrates the usefulness of pupillometry as a tool for experimental research in pragmatics. |
Wendy Troop-Gordon; Robert D. Gordon; Laura Vogel-Ciernia; Elizabeth Ewing Lee; Kari J. Visconti Visual attention to dynamic scenes of ambiguous provocation and children's aggressive behavior Journal Article In: Journal of Clinical Child and Adolescent Psychology, pp. 1–16, 2016. @article{TroopGordon2016, Research on biases in attention related to children's aggression has yielded mixed results. Some research suggests that inattention to social cues and reliance on maladaptive social schemas underlie aggression. Other research suggests that maladaptive social schemas lead aggressive individuals to attend to nonhostile cues. The primary objective of this study was to test the proposition that aggression is related to delayed attention to cues followed by selective attention to nonhostile cues after the provocation has occurred. A second objective was to test whether these biases are associated with aggression only when children hold negative social schemas. The eye fixations of70 children (34 boys, 36 girls; Mage = 11.71 years) were monitored with an eye tracker as they watched video clips of child actors portraying scenes of ambiguous provocation. Aggression was measured using peer-, teacher-, and parent-reports, and children completed a measure ofantisocial and prosocial peer beliefs. Aggressive behavior was associated with greater time until fixation on the provocateur among youth who held antisocial peer beliefs. Aggression was also associated with greater time until fixation on an actor displaying empathy for the victim among children reporting low levels of prosocial peer beliefs. After the provocation, aggression was associated with suppressed attention to an amused peer among children who held negative peer beliefs. Increasing attention to cues in a scene ofambiguous provocation, in conjunction with fostering more positive beliefs about peers, may be effective in reducing hostile responding among aggressive youth. |
Martha M. Shiell; François Champoux; Robert J. Zatorre The right hemisphere planum temporale supports enhanced visual motion detection ability in deaf people: Evidence from cortical thickness Journal Article In: Neural Plasticity, vol. 2016, pp. 7217630, 2016. @article{Shiell2016, After sensory loss, the deprived cortex can reorganize to process information from the remaining modalities, a phenomenon known as cross-modal reorganization. In blind people this cross-modal processing supports compensatory behavioural enhancements in the nondeprived modalities. Deaf people also show some compensatory visual enhancements, but a direct relationship between these abilities and cross-modally reorganized auditory cortex has only been established in an animal model, the congenitally deaf cat, and not in humans. Using T1-weighted magnetic resonance imaging, we measured cortical thickness in the planum temporale, Heschl's gyrus and sulcus, the middle temporal area MT+, and the calcarine sulcus, in early-deaf persons. We tested for a correlation between this measure and visual motion detection thresholds, a visual function where deaf people show enhancements as compared to hearing. We found that the cortical thickness of a region in the right hemisphere planum temporale, typically an auditory region, was greater in deaf individuals with better visual motion detection thresholds. This same region has previously been implicated in functional imaging studies as important for functional reorganization. The structure-behaviour correlation observed here demonstrates this area's involvement in compensatory vision and indicates an anatomical correlate, increased cortical thickness, of cross-modal plasticity. |
Yoshihito Shigihara; Hideyuki Hoshi; Semir Zeki Early visual cortical responses produced by checkerboard pattern stimulation Journal Article In: NeuroImage, vol. 134, pp. 532–539, 2016. @article{Shigihara2016, 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. |
Sergei L. Shishkin; Yuri O. Nuzhdin; Evgeny P. Svirin; Alexander G. Trofimov; Anastasia A. Fedorova; Bogdan L. Kozyrskiy; Boris M. Velichkovsky EEG negativity in fixations used for gaze-based control: Toward converting intentions into actions with an eye-brain-computer interface Journal Article In: Frontiers in Neuroscience, vol. 10, pp. 528, 2016. @article{Shishkin2016, We usually look at an object when we are going to manipulate it. Thus, eye tracking can be used to communicate intended actions. An effective human-machine interface, however, should be able to differentiate intentional and spontaneous eye movements. We report an electroencephalogram (EEG) marker that differentiates gaze fixations used for control from spontaneous fixations involved in visual exploration. Eight healthy participants played a game with their eye movements only. Their gaze-synchronized EEG data (fixation-related potentials, FRPs) were collected during game's control-on and control-off conditions. A slow negative wave with a maximum in the parietooccipital region was present in each participant's averaged FRPs in the control-on conditions and was absent or had much lower amplitude in the control-off condition. This wave was similar but not identical to stimulus-preceding negativity, a slow negative wave that can be observed during feedback expectation. Classification of intentional vs. spontaneous fixations was based on amplitude features from 13 EEG channels using 300 ms length segments free from electrooculogram contamination (200..500 ms relative to the fixation onset). For the first fixations in the fixation triplets required to make moves in the game, classified against control-off data, a committee of greedy classifiers provided 0.90 ± 0.07 specificity and 0.38 ± 0.14 sensitivity. Similar (slightly lower) results were obtained for the shrinkage LDA classifier. The second and third fixations in the triplets were classified at lower rate. We expect that, with improved feature sets and classifiers, a hybrid dwell-based Eye-Brain-Computer Interface (EBCI) can be built using the FRP difference between the intended and spontaneous fixations. If this direction of BCI development will be successful, such a multimodal interface may improve the fluency of interaction and can possibly become the basis for a new input device for paralyzed and healthy users, the EBCI “Wish Mouse”. |
Anthony Shook; Viorica Marian The influence of native-language tones on lexical access in the second language Journal Article In: The Journal of the Acoustical Society of America, vol. 139, no. 6, pp. 3102–3109, 2016. @article{Shook2016, When listening to speech in a second language, bilinguals' perception of acoustic-phonetic properties is often influenced by the features that are important in the native language of the bilingual. Furthermore, changes in the perception of segmental contrasts due to L1 experience can influence L2 lexical access during comprehension. The present study investigates whether the effect of L1 experience on L2 processing seen at the segmental level extends to suprasegmental processing. In an eye-tracking task, Mandarin–English bilinguals heard an auditorily presented English word and selected which of two visually presented Chinese characters represented the correct Mandarin translation. The pitch contour of the spoken word was manipulated to either match or mismatch the lexical tone of the Mandarin translation. Results revealed that bilinguals were significantly faster to correctly identify the target and made earlier eye movements to targets when the suprasegmental information of the word spoken in English matched that of its Mandarin translation. The findings provide compelling evidence for bilinguals' sensitivity to suprasegmental tone information, even when listening to a non-tonal language. These results have important implications for the effect of L1 experience on L2 lexical access and language interaction in bilinguals, and are consistent with a highly interactive account of language processing. |
Tarkeshwar Singh; Christopher M. Perry; Troy M. Herter A geometric method for computing ocular kinematics and classifying gaze events using monocular remote eye tracking in a robotic environment Journal Article In: Journal of NeuroEngineering and Rehabilitation, vol. 13, pp. 1–17, 2016. @article{Singh2016, BACKGROUND: Robotic and virtual-reality systems offer tremendous potential for improving assessment and rehabilitation of neurological disorders affecting the upper extremity. A key feature of these systems is that visual stimuli are often presented within the same workspace as the hands (i.e., peripersonal space). Integrating video-based remote eye tracking with robotic and virtual-reality systems can provide an additional tool for investigating how cognitive processes influence visuomotor learning and rehabilitation of the upper extremity. However, remote eye tracking systems typically compute ocular kinematics by assuming eye movements are made in a plane with constant depth (e.g. frontal plane). When visual stimuli are presented at variable depths (e.g. transverse plane), eye movements have a vergence component that may influence reliable detection of gaze events (fixations, smooth pursuits and saccades). To our knowledge, there are no available methods to classify gaze events in the transverse plane for monocular remote eye tracking systems. Here we present a geometrical method to compute ocular kinematics from a monocular remote eye tracking system when visual stimuli are presented in the transverse plane. We then use the obtained kinematics to compute velocity-based thresholds that allow us to accurately identify onsets and offsets of fixations, saccades and smooth pursuits. Finally, we validate our algorithm by comparing the gaze events computed by the algorithm with those obtained from the eye-tracking software and manual digitization. RESULTS: Within the transverse plane, our algorithm reliably differentiates saccades from fixations (static visual stimuli) and smooth pursuits from saccades and fixations when visual stimuli are dynamic. CONCLUSIONS: The proposed methods provide advancements for examining eye movements in robotic and virtual-reality systems. Our methods can also be used with other video-based or tablet-based systems in which eye movements are performed in a peripersonal plane with variable depth. |
Petra Sinn; Ralf Engbert Small saccades versus microsaccades: Experimental distinction and model-based unification Journal Article In: Vision Research, vol. 118, pp. 132–143, 2016. @article{Sinn2016, Natural vision is characterized by alternating sequences of rapid gaze shifts (saccades) and fixations. During fixations, microsaccades and slower drift movements occur spontaneously, so that the eye is never motionless. Theoretical models of fixational eye movements predict that microsaccades are dynamically coupled to slower drift movements generated immediately before microsaccades, which might be used as a criterion to distinguish microsaccades from small voluntary saccades. Here we investigate a sequential scanning task, where participants generate goal-directed saccades and microsaccades with overlapping amplitude distributions. We show that properties of microsaccades are correlated with precursory drift motion, while amplitudes of goal-directed saccades do not dependent on previous drift epochs. We develop and test a mathematical model that integrates goal-directed and fixational eye movements, including microsaccades. Using model simulations, we reproduce the experimental finding of correlations within fixational eye movement components (i.e., between physiological drift and microsaccades) but not between goal-directed saccades and fixational drift motion. These results lend support to a functional difference between microsaccades and goal-directed saccades, while, at the same time, both types of behavior may be part of an oculomotor continuum that is quantitatively described by our mathematical model. |
Kevin J. Skoblenick; Thilo Womelsdorf; Stefan Everling Ketamine alters outcome-related local field potentials in monkey prefrontal cortex Journal Article In: Cerebral Cortex, vol. 26, no. 6, pp. 2743–2752, 2016. @article{Skoblenick2016, A subanesthetic dose of the noncompetitive N-methyl-d-aspartate receptor antagonist ketamine is known to induce a schizophrenia-like phenotype in humans and nonhuman primates alike. The transient behavioral changes mimic the positive, negative, and cognitive symptoms of the disease but the neural mechanisms behind these changes are poorly understood. A growing body of evidence indicates that the cognitive control processes associated with prefrontal cortex (PFC) regions relies on groups of neurons synchronizing at narrow-band frequencies measurable in the local field potential (LFP). Here,we recorded LFPs from the caudo-lateral PFC of 2 macaque monkeys performing an antisaccade task, which requires the suppression of an automatic saccade toward a stimulus and the initiation of a goal-directed saccade in the opposite direction. Preketamine injection activity showed significant differences in a narrow 20–30 Hz beta frequency band between correct and error trials in the postsaccade response epoch. Ketamine significantly impaired the animals' performance and was associated with a loss of the differences in outcome-specific beta-band power. Instead, we observed a large increase in high-gamma-band activity. Our results suggest that the PFC employs beta-band synchronization to prepare for top–down cognitive control of saccades and the monitoring of task outcome. |
Timothy J. Slattery; Mark Yates; Bernhard Angele Interword and interletter spacing effects during reading revisited: Interactions with word and font characteristics Journal Article In: Journal of Experimental Psychology: Applied, vol. 22, no. 4, pp. 406–422, 2016. @article{Slattery2016, Despite the large number of eye movement studies conducted over the past 30+ years, relatively few have examined the influence that font characteristics have on reading. However, there has been renewed interest in 1 particular font characteristic, letter spacing, which has both theoretical (visual word recognition) and applied (font design) importance. Recently published results that letter spacing has a bigger impact on the reading performance of dyslexic children have perhaps garnered the most attention (Zorzi et al., 2012). Unfortunately, the effects of increased interletter spacing have been mixed with some authors reporting facilitation and others reporting inhibition (van den Boer & Hakvoort, 2015). The authors present findings from 3 experiments designed to resolve the seemingly inconsistent letter-spacing effects and provide clarity to researchers and font designers and researchers. The results indicate that the direction of spacing effects depend on the size of the default spacing chosen by font developers. Experiment 3 found that interletter spacing interacts with interword spacing, as the required space between words depends on the amount of space used between letters. Interword spacing also interacted with word type as the inhibition seen with smaller interword spacing was evident with nouns and verbs but not with function words. |
B. J. Sleezer; M. D. Castagno; Benjamin Y. Hayden Rule encoding in orbitofrontal cortex and striatum guides selection Journal Article In: Journal of Neuroscience, vol. 36, no. 44, pp. 11223–11237, 2016. @article{Sleezer2016a, Active maintenance of rules, like other executive functions, is often thought to be the domain of a discrete executive system. Analternative view is that rule maintenance is a broadly distributed function relying on widespread cortical and subcortical circuits. Tentative evidence supporting this view comes from research showing some rule selectivity in the orbitofrontal cortex and dorsal striatum. We recorded in these regions and in the ventral striatum, which has not been associated previously with rule representation, as macaques performed a Wisconsin Card Sorting Task. We found robust encoding ofrule category (color vs shape) and rule identity (six possible rules) in all three regions. Rule identity modulated responses to potential choice targets, suggesting that rule information guides behavior by highlighting choice targets. The effects that we observed were not explained by differences in behavioral performance across rules and thus cannot be attributed to reward expectation. Our results suggest that rule maintenance and rule-guided selection of options are distributed processes and provide new insight into orbital and striatal contributions to executive control. |
Brianna J. Sleezer; Benjamin Y. Hayden Differential contributions of ventral and dorsal striatum to early and late phases of cognitive set reconfiguration Journal Article In: Journal of Cognitive Neuroscience, vol. 28, no. 12, pp. 1849–1864, 2016. @article{Sleezer2016, Flexible decision-making, a defining feature of human cognition, is typically thought of as a canonical pFC function. Recent work suggests that the striatum may participate as well; however, its role in this process is not well understood. We recorded activity of neurons in both the ventral (VS) and dorsal (DS) striatum while rhesus macaques performed a version of the Wisconsin Card Sorting Test, a classic test of flexibility. Our version of the task involved a trial-and-error phase before monkeys could identify the correct rule on each block. We observed changes in firing rate in both regions when monkeys switched rules. Specifically, VS neurons demonstrated switch-related activity early in the trial-and-error period when the rule needed to be updated, and a portion of these neurons signaled information about the switch context (i.e., whether the switch was intradimensional or extradimensional). Neurons in both VS and DS demonstrated switch-related activity at the end of the trial-and-error period, immediately before the rule was fully established and main- tained, but these signals did not carry any information about switch context. We also observed associative learning signals (i.e., specific responses to options associated with rewards in the presentation period before choice) that followed the same pattern as switch signals (early in VS, later in DS). Taken together, these results endorse the idea that the striatum participates directly in cognitive set reconfiguration and suggest that single neurons in the striatum may contribute to a functional handoff from the VS to the DS during reconfiguration processes. |
Z. K. Sun; J. Y. Wang; F. Luo Experimental pain induces attentional bias that is modified by enhanced motivation: An eye tracking study Journal Article In: European Journal of Pain, vol. 20, no. 8, pp. 1266–1277, 2016. @article{Sun2016, Background: In this study, the effects of prior pain experience and motivation on attentional bias towards pain-related information were investigated within two visual-probe tasks via eye movement behaviours. It is hypothesized that pain experience would induce stronger attentional bias and such bias could be suppressed by the motivation to avoid impeding pain.Methods: All participants took part in visual-probe tasks with pictures and words as stimuli that are typically used in studies of attentional bias. They were allocated to three groups: no-pain (NP) group, performing tasks without experiencing pain; pain-experience (PE) group, performing the same tasks following painful stimuli; and pain-experience-with-motivation (PEM) group, undergoing the same procedure as PE group with additional instructions about avoiding impeding pain. Eye movements were recorded during the tasks.Results: The eye movement data showed that: (1) participants in the PE group exhibited stronger attention bias towards painful pictures than those in the NP group; (2) the attentional bias towards painful pictures was significantly reduced in the PEM group as compared to the PE group. By contrast, the verbal task failed to find these effects using sensory pain words as stimuli.Conclusion: This study was the first that revealed the impact of acute experimental pain on attentional bias towards pain-related information in healthy individuals through eye tracking. It may provide a possible solution to reduce hypervigilance towards pain-related information by altering the motivational relevance. WHAT DOES THIS STUDY ADD?: (1) This study revealed the impact of experimental pain on attentional bias in healthy individuals; (2) This study may provide a possible approach of altering motivational relevance to control the pain-induced attentional bias towards pain-related information. |
Yao-Ting Sung; Jih-Ho Cha; Jung-Yueh Tu; Ming-Da Wu; Wei-Chun Lin Investigating the processing of relative clauses in Mandarin Chinese: Evidence from eye-movement aata Journal Article In: Journal of Psycholinguistic Research, vol. 45, no. 5, pp. 1089–1113, 2016. @article{Sung2016, A number of previous studies on Chinese relative clauses (RC) have reported conflicting results on processing asymmetry. This study aims to revisit the prevalent debate on whether subject-extracted RCs (SRC) or object-extracted RCs (ORC) are easier to process by using the eye-movement technique. In the current study, the data are analyzed in terms of the gaze duration and regression of eye-movement in three critical areas: head noun, embedded verb, and RC-modifying noun phrase as subject. The results show an ORC preference for the processing of RC structures, which supports the word-order account and the Dependency Locality Theory, and a better cross-clausal integration for SRC, which supports the perspective-shift account. The processing asymmetry in Chinese RCs are discussed under relevant theoretical accounts, such as structure-based, memory-based, and perspective shift accounts. We argue that the findings are associated with the syntactic nature of Chinese (a head-initial language with pre-nominal RCs). |
Yao-Ting Sung; Jung-Yueh Tu; Jih-Ho Cha; Ming-Da Wu Processing preference toward object-extracted relative clauses in mandarin chinese by l1 and l2 speakers: An eye-tracking study Journal Article In: Frontiers in Psychology, vol. 7, pp. 4, 2016. @article{Sung2016a, The current study employed an eye-movement technique with an attempt to explore the reading patterns for the two types of Chinese relative clauses, subject-extracted relative clauses (SRCs) and object-extracted relative clauses (ORCs), by native speakers (L1), and Japanese learners (L2) of Chinese. The data were analyzed in terms of gaze duration, regression path duration, and regression rate on the two critical regions, head noun, and embedded verb. The results indicated that both the L1 and L2 participants spent less time on the head nouns in ORCs than in SRCs. Also, the L2 participants spent less time on the embedded verbs in ORCs than in SRCs and their regression rate for embedded verbs was generally lower in ORCs than in SRC. The findings showed that the participants experienced less processing difficulty in ORCs than SRCs. These results suggest an ORC preference in L1 and L2 speakers of Chinese, which provides evidence in support of linear distance hypothesis and implies that the syntactic nature of Chinese is at play in the RC processing. |
John Sustersic; Brad Wyble; Siddharth Advani; Vijaykrishnan Narayanan Towards a unified multiresolution vision model for autonomous ground robots Journal Article In: Robotics and Autonomous Systems, vol. 75, pp. 221–232, 2016. @article{Sustersic2016, While remotely operated unmanned vehicles are increasingly a part of everyday life, truly autonomous robots capable of independent operation in dynamic environments have yet to be realized-particularly in the case of ground robots required to interact with humans and their environment. We present a unified multiresolution vision model for this application designed to provide the wide field of view required to maintain situational awareness and sufficient visual acuity to recognize elements of the environment while permitting feasible implementations in real-time vision applications. The model features a kind of color-constant processing through single-opponent color channels and contrast invariant oriented edge detection using a novel implementation of the Combination of Receptive Fields model. The model provides color and edge-based salience assessment, as well as a compressed color image representation suitable for subsequent object identification. We show that bottom-up visual saliency computed using this model is competitive with the current state-of-the-art while allowing computation in a compressed domain and mimicking the human visual system with nearly half (45%) of computational effort focused within the fovea. This method reduces storage requirement of the image pyramid to less than 5% of the full image, and computation in this domain reduces model complexity in terms of both computational costs and memory requirements accordingly. We also quantitatively evaluate the model for its application domain by using it with a camera/lens system with a 185° field of view capturing 3.5M pixel color images by using a tuned salience model to predict human fixations. |
Benjamin Swets; Christopher A. Kurby Eye movements reveal the influence of event structure on reading behavior Journal Article In: Cognitive Science, vol. 40, no. 2, pp. 466–480, 2016. @article{Swets2016, When we read narrative texts such as novels and newspaper articles, we segment information presented in such texts into discrete events, with distinct boundaries between those events. But do our eyes reflect this event structure while reading? This study examines whether eye movements during the reading of discourse reveal how readers respond online to event structure. Participants read narrative passages as we monitored their eye movements. Several measures revealed that event structure predicted eye movements. In two experiments, we found that both early and overall reading times were longer for event boundaries. We also found that regressive saccades were more likely to land on event boundaries, but that readers were less likely to regress out of an event boundary. Experiment 2 also demonstrated that tracking event structure carries a working memory load. Eye movements provide a rich set of online data to test the cognitive reality of event segmentation during reading. |
Martin Szinte; Donatas Jonikaitis; Martin Rolfs; Patrick Cavanagh; Heiner Deubel Presaccadic motion integration between current and future retinotopic locations of attended objects Journal Article In: Journal of Neurophysiology, vol. 116, no. 4, pp. 1592–1602, 2016. @article{Szinte2016, Object tracking across eye movements is thought to rely on pre-saccadic updating of attention between the object's current and its "remapped" location (i.e., the post-saccadic retinotopic location). Here we report evidence for a bi-focal, pre-saccadic sampling between these two positions. While preparing a saccade, participants viewed four spatially separated random dot kinematograms, one of which was cued by a colored flash. They reported the direction of a coherent motion signal at the cued location while a second signal occurred simultaneously either at the cue's remapped location or at one of several control locations. Motion integration between the signals occurred only when the two motion signals were congruent and were shown at the cue and at its remapped location. This shows that the visual system integrates features between both the current and the future retinotopic locations of an attended object, and that such pre-saccadic sampling is feature-specific. |
Jérôme Tagu; Karine Doré-Mazars; Christelle Lemoine-Lardennois; Dorine Vergilino-Perez How eye dominance strength modulates the influence of a distractor on saccade accuracy Journal Article In: Investigative Ophthalmology & Visual Science, vol. 57, no. 2, pp. 534–543, 2016. @article{Tagu2016, PURPOSE. Neuroimaging studies have shown that the dominant eye is linked preferentially to the ipsilateral primary visual cortex. However, its role in perception still is misunderstood. We examined the influence of eye dominance and eye dominance strength on saccadic parameters, contrasting stimulations presented in the two hemifields. METHODS. Participants with contrasted eye dominance (left or right) and eye dominance strength (strong or weak) were asked to make a saccade toward a target displayed at 5degree or 7degree left or right of a fixation cross. In some trials, a distractor at 3degree of eccentricity also was displayed either in the same hemifield as the target (to induce a global effect on saccade amplitude) or in the opposite hemifield (to induce a remote distractor effect on saccade latency). RESULTS. Eye dominance did influence saccade amplitude as participants with strong eye dominance showed more accurate saccades toward the target (weaker global effect) in the hemifield contralateral to the dominant eye than in the ipsilateral one. Such asymmetry was not found in participants with weak eye dominance or when a remote distractor was used. CONCLUSIONS. We show that eye dominance strength influences saccade target selection. We discuss several arguments supporting the view that such advantage may be linked to the relationship between the dominant eye and ipsilateral hemisphere. |
Tobias Talanow; Anna-Maria Kasparbauer; Maria Steffens; Inga Meyhöfer; Bernd Weber; Nikolaos Smyrnis; Ulrich Ettinger Facing competition: Neural mechanisms underlying parallel programming of antisaccades and prosaccades Journal Article In: Brain and Cognition, vol. 107, pp. 37–47, 2016. @article{Talanow2016, 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. |
Heng Ru May Tan; Joachim Gross; P. J. Uhlhaas MEG sensor and source measures of visually induced gamma-band oscillations are highly reliable Journal Article In: NeuroImage, vol. 137, pp. 34–44, 2016. @article{Tan2016, 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 |
Balaji Sriram; Philip M. Meier; Pamela Reinagel Temporal and spatial tuning of dorsal lateral geniculate nucleus neurons in unanesthetized rats Journal Article In: Journal of Neurophysiology, vol. 115, pp. 2658–2671, 2016. @article{Sriram2016, Visual response properties of neurons in the dorsolateral geniculate nucleus (dLGN) have been well de- scribed in several species, but not in rats. Analysis of responses from the unanesthetized rat dLGN will be needed to develop quantitative models that account for visual behavior of rats. We recorded visual responses from 130 single units in the dLGN of 7 unanesthetized rats. We report the response amplitudes, temporal frequency, and spatial frequency sensitivities in this population of cells. In response to 2-Hz visual stimulation, dLGN cells fired 15.9 ⫾ 11.4 spikes/s (mean ⫾ SD) modulated by 10.7 ⫾ 8.4 spikes/s about the mean. The optimal temporal frequency for full-field stimulation ranged from 5.8 to 19.6 Hz across cells. The temporal high-frequency cutoff ranged from 11.7 to 33.6 Hz. Some cells responded best to low temporal frequency stimulation (low pass), and others were strictly bandpass; most cells fell between these extremes. At 2- to 4-Hz temporal modulation, the spatial frequency of drifting grating that drove cells best ranged from 0.008 to 0.18 cycles per degree (cpd) across cells. The high-frequency cutoff ranged from 0.01 to 1.07 cpd across cells. The majority of cells were driven best by the lowest spatial frequency tested, but many were partially or strictly bandpass. We conclude that single units in the rat dLGN can respond vigorously to temporal modulation up to at least 30 Hz and spatial detail up to 1 cpd. Tuning properties were hetero- geneous, but each fell along a continuum; we found no obvious clustering into discrete cell types along these dimensions. |
Mathew Stange; Amanda Barry; Jolene Smyth; Kristen Olson Effects of smiley face scales on visual processing of satisfaction questions in web surveys Journal Article In: Social Science Computer Review, vol. 36, no. 6, pp. 756–766, 2016. @article{Stange2016, Web surveys permit researchers to use graphic or symbolic elements alongside the text of response options to help respondents process the categories. Smiley faces are one example used to communicate positive and negative domains. How respondents visually process these smiley faces, including whether they detract from the question's text, is understudied. We report the results of two eye-tracking experiments in which satisfaction questions were asked with and without smiley faces. Respondents to the questions with smiley faces spent less time reading the question stem and response option text than respondents to the questions without smiley faces, but the response distributions did not differ by version. We also find support that lower literacy respondents rely more on the smiley faces than higher literacy respondents. |
Maria Steffens; B. Becker; C. Neumann; Anna-Maria Kasparbauer; Inga Meyhöfer; Bernd Weber; Mitul A. Mehta; R. Hurlemann; Ulrich Ettinger Effects of ketamine on brain function during smooth pursuit eye movements Journal Article In: Human Brain Mapping, vol. 37, no. 11, pp. 4047–4060, 2016. @article{Steffens2016, 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. |
Neil Stewart; Simon Gächter; Takao Noguchi; Timothy L. Mullett Eye movements in strategic choice Journal Article In: Journal of Behavioral Decision Making, vol. 29, no. 2-3, pp. 137–156, 2016. @article{Stewart2016, In risky and other multiattribute choices, the process of choosing is well described by random walk or drift diffusion models in which evidence is accumulated over time to threshold. In strategic choices, level-k and cognitive hierarchy models have been offered as accounts of the choice process, in which people simulate the choice processes of their opponents or partners. We recorded the eye movements in 2 × 2 symmetric games including dominance-solvable games like prisoner's dilemma and asymmetric coordination games like stag hunt and hawk–dove. The evidence was most consistent with the accumulation of payoff differences over time: we found longer duration choices with more fixations when payoffs differences were more finely balanced, an emerging bias to gaze more at the payoffs for the action ultimately chosen, and that a simple count of transitions between payoffs—whether or not the comparison is strategically informative—was strongly associated with the final choice. The accumulator models do account for these strategic choice process measures, but the level-k and cognitive hierarchy models do not. |
Neil Stewart; Frouke Hermens; William J. Matthews Eye movements in risky choice Journal Article In: Journal of Behavioral Decision Making, vol. 29, no. 2-3, pp. 116–136, 2016. @article{Stewart2016a, We asked participants to make simple risky choices while we recorded their eye movements. We built a complete statistical model of the eye movements and found very little systematic variation in eye movements over the time course of a choice or across the different choices. The only exceptions were finding more (of the same) eye movements when choice options were similar, and an emerging gaze bias in which people looked more at the gamble they ultimately chose. These findings are inconsistent with prospect theory, the priority heuristic, or decision field theory. However, the eye movements made during a choice have a large relationship with the final choice, and this is mostly independent from the contribution of the actual attribute values in the choice options. That is, eye movements tell us not just about the processing of attribute values but also are independently associated with choice. The pattern is simple—people choose the gamble they look at more often, independently of the actual numbers they see—and this pattern is simpler than predicted by decision field theory, decision by sampling, and the parallel constraint satisfaction model. |
Mallory C. Stites; Kara D. Federmeier; Kiel Christianson Do morphemes matter when reading compound words with transposed letters? Evidence from eye-tracking and event-related potentials Journal Article In: Language, Cognition and Neuroscience, pp. 1–23, 2016. @article{Stites2016, The current study investigates the online processing consequences of encountering compound words with transposed letters (TLs), to determine if cross-morpheme TLs are more disruptive to reading than those within a single morpheme, as would be predicted by accounts of obligatory morpho-orthopgrahic decomposition. Two measures of online processing, eye movements and event-related potentials (ERPs), were collected in separate experiments. Participants read sentences containing correctly spelled compound words (cupcake), or compounds with TLs occurring either across morphemes (cucpake) or within one morpheme (cupacke). Results showed that between- and within-morpheme transpositions produced equal processing costs in both measures, in the form of longer reading times (Experiment 1) and a late posterior positivity (Experiment 2) that did not differ between conditions. Findings converge to suggest that within- and between-morpheme TLs are equally disruptive to recognition, providing evidence against obligatory morpho-orthographic processing and in favour of whole-word access of English compound words during sentence reading. |
Viola S. Störmer; George A. Alvarez Attention alters perceived attractiveness Journal Article In: Psychological Science, vol. 27, no. 4, pp. 563–571, 2016. @article{Stoermer2016, Can attention alter the impression of a face? Previous studies showed that attention modulates the appearance of lower-level visual features. For instance, attention can make a simple stimulus appear to have higher contrast than it actually does. We tested whether attention can also alter the perception of a higher-order property—namely, facial attractiveness. We asked participants to judge the relative attractiveness of two faces after summoning their attention to one of the faces using a briefly presented visual cue. Across trials, participants judged the attended face to be more attractive than the same face when it was unattended. This effect was not due to decision or response biases, but rather was due to changes in perceptual processing of the faces. These results show that attention alters perceived facial attractiveness, and broadly demonstrate that attention can influence higher-level perception and may affect people's initial impressions of one another. |
Caleb E. Strait; Brianna J. Sleezer; Tommy C. Blanchard; Habiba Azab; Meghan D. Castagno; Benjamin Y. Hayden Neuronal selectivity for spatial positions of offers and choices in five reward regions Journal Article In: Journal of Neurophysiology, vol. 115, no. 3, pp. 1098–1111, 2016. @article{Strait2016, When we evaluate an option, how is the neural representation of its value linked to information that identifies it, such as its position in space? We hypothesized that value information and identity cues are not bound together at a particular point but are represented together at the single unit level throughout the entirety of the choice process. We examined neuronal responses in two-option gambling tasks with lateralized and asynchronous presentation of offers in five reward regions: orbitofrontal cortex (OFC, area 13), ventromedial prefrontal cortex (vmPFC, area 14), ventral striatum (VS), dorsal anterior cingulate cortex (dACC), and subgenual anterior cingulate cortex (sgACC, area 25). Neuronal responses in all areas are sensitive to the positions of both offers and of choices. This selectivity is strongest in reward-sensitive neurons, indicating that it is not a property of a specialized subpopulation of cells. We did not find consistent contralateral or any other organization to these responses, indicating that they may be difficult to detect with aggregate measures like neuro-imaging or studies of lesion effects. These results suggest that value coding is wed to factors that identify the object throughout the reward system and suggest a possible solution to the binding problem raised by abstract value encoding schemes. |
Gregory P. Strauss; Kathryn L. Ossenfort; Kayla M. Whearty In: PLoS ONE, vol. 11, no. 11, pp. e0162290, 2016. @article{Strauss2016, Multiple emotion regulation strategies have been identified and found to differ in their effectiveness at decreasing negative emotions. One reason for this might be that individual strategies are associated with differing levels of cognitive demand and require distinct patterns of visual attention to achieve their effects. In the current study, we tested this hypothesis in a sample of psychiatrically healthy participants (n = 25) who attempted to down-regulate negative emotion to photographs from the International Affective Picture System using cognitive reappraisal or distraction. Eye movements, pupil dilation, and subjective reports of negative emotionality were obtained for reappraisal, distraction, unpleasant passive viewing, and neutral passive viewing conditions. Behavioral results indicated that reappraisal and distraction successfully decreased self-reported negative affect relative to unpleasant passive viewing. Successful down regulation of negative affect was associated with different patterns of visual attention across regulation strategies. During reappraisal, there was an initial increase in dwell time to arousing scene regions and a subsequent shift away from these regions during later portions of the trial, whereas distraction was associated with reduced total dwell time to arousing interest areas throughout the entire stimulus presentation. Pupil dilation was greater for reappraisal than distraction or unpleasant passive viewing, suggesting that reappraisal may recruit more effortful cognitive control processes. Furthermore, greater decreases in self-reported negative emotion were associated with a lower proportion of dwell time within arousing areas of interest. These findings suggest that different emotion regulation strategies necessitate different patterns of visual attention to be effective and that individual differences in visual attention predict the extent to which individuals can successfully decrease negative emotion using reappraisal and distraction. |
Natale Stucchi; Lisa Scocchia; Alessandro Carlini When geometry constrains vision: Systematic misperceptions within geometrical configurations Journal Article In: PLoS ONE, vol. 11, no. 3, pp. e0151488, 2016. @article{Stucchi2016, How accurate are we in reproducing a point within a simple shape? This is the empirical question we addressed in this work. Participants were presented with a tiny disk embedded in an empty circle (Experiment 1 and 3) or in a square (Experiment 2). Shortly afterwards, the disk vanished and they had to reproduce the previously seen disk position within the empty shape by means of the mouse cursor, as accurately as possible. Several loci inside each shape were tested. We found that the space delimited by a circle and by a square is not homogeneous and the observed distortion appears to be consistent across observers and specific for the two tested shapes. However, a common pattern can be identified when reproducing geometrical loci enclosed in a shape: errors are shifted toward the periphery in the region around the centre and toward the centre in the region nearby the edges. The error absolute value declines progressively as we approach an equilibrium contour line between the centre and the outline of the shape where the error is null. These results suggest that enclosing an empty space within a shape imposes an organization to it an warps its metrics: not only the perceived loci inside a shape are not the same as the geometrical loci, but they are misperceived in a systematic way that is functional to the correct identification of the centre of the shape. Eye movements recordings (Experiment 3) are consistent with this interpretation of the data. |
Alessandro Benedetto; Paola Binda Dissociable saccadic suppression of pupillary and perceptual responses to light Journal Article In: Journal of Neurophysiology, vol. 115, no. 3, pp. 1243–1251, 2016. @article{Benedetto2016, We measured pupillary constrictions in response to full-screen flashes of variable luminance, occurring either at the onset of a saccadic eye movement or well before/after it. A large fraction of perisaccadic flashes were undetectable to the subjects, consistent with saccadic suppression of visual sensitivity. Likewise, pupillary responses to perisaccadic flashes were strongly suppressed. However, the two phenomena appear to be dissociable. Across subjects and luminance levels of the flash stimulus, there were cases in which conscious perception of the flash was completely depleted yet the pupillary response was clearly present, as well as cases in which the opposite occurred. On one hand, the fact that pupillary light responses are subject to saccadic suppression reinforces evidence that this is not a simple reflex but depends on the integration of retinal illumination with complex "extraretinal" cues. On the other hand, the relative independence of pupillary and perceptual responses suggests that suppression acts separately on these systems-consistent with the idea of multiple visual pathways that are differentially affected by saccades. |
Brittany Benjamin; Christopher Macomb; Alisha Martin; Aaron L. Cecala Can color act as a contextual cue in human saccadic adaptation? Journal Article In: Bios, vol. 87, no. 1, pp. 9–20, 2016. @article{Benjamin2016, When the head does not move, rapid movements of the eyes called saccades are used to redirect the line of sight. Saccades are defined by a series of metrical and kinematic (evolution of a movement as a function of time) relationships. For example, the amplitude of a saccade made from one visual target to another is roughly 90% of the distance between the initial fixation point (T0) and the peripheral target (T1). However, this stereotypical relationship between saccade amplitude and initial retinal error (jT1-Initial Eye Positionj) may be altered, either increased or decreased, by surreptitiously displacing a visual target during an ongoing saccade. This form of saccadic adaptation has been described in both humans and monkeys. We investigated the effects of a contextual cue (target color) on the magnitude of human saccadic adaptation using an eye tracker to measure our subjects' eye position. Our results indicate that target color cannot be used by the eye movement control system to elicit differential changes in motor output regardless of whether the color cues are randomly intermixed or presented sequentially. |
Valerie Benson; Monica S. Castelhano; Philippa L. Howard; Nida Latif; Keith Rayner Looking, seeing and believing in autism: Eye movements reveal how subtle cognitive processing differences impact in the social domain Journal Article In: Autism Research, vol. 9, no. 8, pp. 879–887, 2016. @article{Benson2016, Adults with High Functioning Autism Spectrum Disorders (ASD) viewed scenes with people in them, while having their eye movements recorded. The task was to indicate, using a button press, whether the pictures were normal, or in some way weird or odd. Oddities in the pictures were categorized as violations of either perceptual or social norms. Compared to a Typically Developed (TD) control group, the ASD participants were equally able to categorize the scenes as odd or normal, but they took longer to respond. The eye movement patterns showed that the ASD group made more fixations and revisits to the target areas in the odd scenes compared with the TD group. Additionally, when the ASD group first fixated the target areas in the scenes, they failed to initially detect the social oddities. These two findings have clear implications for processing difficulties in ASD for the social domain, where it is important to detect social cues on-line, and where there is little opportunity to go back and recheck possible cues in fast dynamic interactions. |
Palash Bera; Louis Philippe Sirois Displaying background maps in business intelligence dashboards Journal Article In: Iranian Journal of Psychiatry, vol. 18, no. 5, pp. 58–65, 2016. @article{Bera2016, Business data in geographic maps, called data maps, can be displayed via business intelligence dashboards. An important emerging feature is the use of background maps that overlap with existing data maps. Here, the authors examine the usefulness of background maps in dashboards and investigate how much cognitive effort users put in when they use dashboards with background maps as compared to dashboards without them. To test the extent of cognitive effort, the authors conducted an eye-tracking study in which users performed a decision-making task with maps in dashboards. In a separate study, users were asked directly about the mental effort required to perform tasks with the dashboards. Both studies identified that when users use background maps, they required less cognitive effort than users who use dashboards in which the information on the background map is represented in another form, such as a bar chart. |
Jean-Baptiste Bernard; Susana T. L. Chung The role of external features in face recognition with central vision loss Journal Article In: Optometry and Vision Science, vol. 93, no. 5, pp. 510–520, 2016. @article{Bernard2016a, PURPOSE: We evaluated how the performance of recognizing familiar face images depends on the internal (eyebrows, eyes, nose, mouth) and external face features (chin, outline of face, hairline) in individuals with central vision loss. METHODS: In experiment 1, we measured eye movements for four observers with central vision loss to determine whether they fixated more often on the internal or the external features of face images while attempting to recognize the images. We then measured the accuracy for recognizing face images that contained only the internal, only the external, or both internal and external features (experiment 2) and for hybrid images where the internal and external features came from two different source images (experiment 3) for five observers with central vision loss and four age-matched control observers. RESULTS: When recognizing familiar face images, approximately 40% of the fixations of observers with central vision loss was centered on the external features of faces. The recognition accuracy was higher for images containing only external features (66.8 ± 3.3% correct) than for images containing only internal features (35.8 ± 15.0%), a finding contradicting that of control observers. For hybrid face images, observers with central vision loss responded more accurately to the external features (50.4 ± 17.8%) than to the internal features (9.3 ± 4.9%), whereas control observers did not show the same bias toward responding to the external features. CONCLUSIONS: Contrary to people with normal vision who rely more on the internal features of face images for recognizing familiar faces, individuals with central vision loss show a higher dependence on using external features of face images. |
Raymond Bertram; Johanna K. Kaakinen; Frank Bensch; Laura Helle; Eila Lantto; Pekka Niemi; Nina Lundbom Eye movements of radiologists reflect expertise in CT study interpretation: A potential tool to measure resident development Journal Article In: Radiology, vol. 281, no. 3, pp. 805–815, 2016. @article{Bertram2016, PURPOSE: To establish potential markers of visual expertise in eye movement (EM) patterns of early residents, advanced residents, and specialists who interpret abdominal computed tomography (CT) studies. MATERIAL AND METHODS: The institutional review board approved use of anonymized CT studies as research materials and to obtain anonymized eye-tracking data from volunteers. Participants gave written informed consent. RESULTS: Early residents (n = 15), advanced residents (n = 14), and specialists (n = 12) viewed 26 abdominal CT studies as a sequence of images at either 3 or 5 frames per second while EMs were recorded. Data were analyzed by using linear mixed-effects models. Early residents' detection rate decreased with working hours (odds ratio, 0.81; 95% confidence interval [CI]: 0.73, 0.91; P = .001). They detected less of the low visual contrast (but not of the high visual contrast) lesions (45% [13 of 29]) than did specialists (62% [18 of 29]) (odds ratio, 0.39; 95% CI: 0.25, 0.61; P , .001) or advanced residents (56% [16 of 29]) (odds ratio, 0.55; 95% CI: 0.33, 0.93; P = .024). Specialists and advanced residents had longer fixation durations at 5 than at 3 frames per second (specialists: b = .01; 95% CI: .004, .026; P = .008; advanced residents: b = .04; 95% CI: .03, .05; P , .001). In the presence of lesions, saccade lengths of specialists shortened more than those of advanced (b = .02; 95% CI: .007, .04; P = .003) and of early residents (b = .02; 95% CI: .008, 0.04; P = .003). Irrespective of expertise, high detection rate correlated with greater reduction of saccade length in the presence of lesions (b = 2.10; 95% CI: 2.16, 2.04; P = .002) and greater increase at higher presentation speed (b = .11; 95% CI: .04, .17; P = .001). CONCLUSION: Expertise in CT reading is characterized by greater adaptivity in EM patterns in response to the demands of the task and environment. |
Federica Bianchi; Sébastien Santurette; Dorothea Wendt; Torsten Dau Pitch discrimination in musicians and non-musicians: Effects of harmonic resolvability and processing effort Journal Article In: JARO - Journal of the Association for Research in Otolaryngology, vol. 17, no. 1, pp. 69–79, 2016. @article{Bianchi2016, Musicians typically show enhanced pitch discrimination abilities compared to non-musicians. The present study investigated this perceptual enhancement behaviorally and objectively for resolved and unresolved complex tones to clarify whether the enhanced performance in musicians can be ascribed to increased peripheral frequency selectivity and/or to a different processing effort in performing the task. In a first experiment, pitch discrimination thresholds were obtained for harmonic complex tones with fundamental frequencies (F0s) between 100 and 500 Hz, filtered in either a low- or a high-frequency region, leading to variations in the resolvability of audible harmonics. The results showed that pitch discrimination performance in musicians was enhanced for resolved and unresolved complexes to a similar extent. Additionally, the harmonics became resolved at a similar F0 in musicians and non-musicians, suggesting similar peripheral frequency selectivity in the two groups of listeners. In a follow-up experiment, listeners' pupil dilations were measured as an indicator of the required effort in performing the same pitch discrimination task for conditions of varying resolvability and task difficulty. Pupillometry responses indicated a lower processing effort in the musicians versus the non-musicians, although the processing demand imposed by the pitch discrimination task was individually adjusted according to the behavioral thresholds. Overall, these findings indicate that the enhanced pitch discrimination abilities in musicians are unlikely to be related to higher peripheral frequency selectivity and may suggest an enhanced pitch representation at more central stages of the auditory system in musically trained listeners. |
Jutta Billino; Jürgen Hennig; Karl R. Gegenfurtner The role of dopamine in anticipatory pursuit eye movements: Insights from genetic polymorphisms in healthy adults Journal Article In: eNeuro, vol. 3, no. 6, pp. 1–13, 2016. @article{Billino2016, There is a long history of eye movement research in patients with psychiatric diseases for which dysfunctions of neurotransmission are considered to be the major pathologic mechanism. However, neuromodulation of oculomotor control is still hardly understood. We aimed to investigate in particular the impact of dopamine on smooth pursuit eye movements. Systematic variability in dopaminergic transmission due to genetic polymorphisms in healthy subjects offers a noninvasive opportunity to determine functional associations. We measured smooth pursuit in 110 healthy subjects genotyped for two well-documented polymorphisms, the COMT Val158Met polymorphism and the SLC6A3 3′-UTR-VNTR polymorphism. Pursuit paradigms were chosen to particularly assess the ability of the pursuit system to initiate tracking when target motion onset is blanked, reflecting the impact of extraretinal signals. In contrast, when following a fully visible target sensory, retinal signals are available. Our results highlight the crucial functional role of dopamine for anticipatory, but not for sensory-driven, pursuit processes. We found the COMT Val158Met polymorphism specifically associated with anticipatory pursuit parameters, emphasizing the dominant impact of prefrontal dopamine activity on complex oculomotor control. In contrast, modulation of striatal dopamine activity by the SLC6A3 3′-UTR-VNTR polymorphism had no significant functional effect. Though often neglected so far, individual differences in healthy subjects provide a promising approach to uncovering functional mechanisms and can be used as a bridge to understanding deficits in patients. |
Nicola Binetti; Charlotte Harrison; Alan Johnston; Isabelle Mareschal Pupil dilation as an index of preferred mutual gaze duration Journal Article In: Royal Society Open Science, vol. 3, no. 16008, pp. 1–11, 2016. @article{Binetti2016, Most animals look at each other to signal threat or interest. In humans, this social interaction is usually punctuated with brief periods of mutual eye contact. Deviations from this pattern of gazing behaviour generally make us feel uncomfortable and are a defining characteristic of clinical conditions such as autism or schizophrenia, yet it is unclear what constitutes normal eye contact.Here, we measured, across a wide range of ages, cultures and personality types, the period of direct gaze that feels comfortable and examined whether autonomic factors linked to arousal were indicative of people's preferred amount of eye contact. Surprisingly, we find that preferred period of gaze duration is not dependent on fundamental characteristics such as gender, personality traits or attractiveness. However, we do find that subtle pupillary changes, indicative of physiological arousal, correlate with the amount of eye contact people find comfortable. Specifically, people preferring longer durations of eye contact display faster increases in pupil size when viewing another person than those preferring shorter durations. These results reveal that a person's preferred duration of eye contact is signalled by physiological indices (pupil dilation) beyond volitional control that may play a modulatory role in gaze behaviour. |
Julia Bahnmueller; Stefan Huber; Hans-Christoph Nuerk; Silke M. Göbel; Korbinian Moeller Processing multi-digit numbers: a translingual eye-tracking study Journal Article In: Psychological Research, vol. 80, no. 3, pp. 422–433, 2016. @article{Bahnmueller2016, The present study aimed at investigating the underlying cognitive processes and language specificities of three-digit number processing. More specifically, it was intended to clarify whether the single digits of three-digit numbers are processed in parallel and/or sequentially and whether processing strategies are influenced by the inversion of number words with respect to the Arabic digits [e.g., 43: dreiundvierzig (“three and forty”)] and/or by differences in reading behavior of the respective first language. Therefore, English- and German-speaking adults had to complete a three-digit number comparison task while their eye-fixation behavior was recorded. Replicating previous results, reliable hundred-decade-compatibility effects (e.g., 742_896: hundred-decade compatible because 7 < 8 and 4 < 9; 362_517: hundred-decade incompatible because 3 < 5 but 6 > 1) for English- as well as hundred-unit-compatibility effects for English- and German-speaking participants were observed, indicating parallel processing strategies. While no indices of partial sequential processing were found for the English-speaking group, about half of the German-speaking participants showed an inverse hundred-decade-compatibility effect accompanied by longer inspection time on the hundred digit indicating additional sequential processes. Thereby, the present data revealed that in transition from two- to higher multi-digit numbers, the homogeneity of underlying processing strategies varies between language groups. The regular German orthography (allowing for letter-by-letter reading) and its associated more sequential reading behavior may have promoted sequential processing strategies in multi-digit number processing. Furthermore, these results indicated that the inversion of number words alone is not sufficient to explain all observed language differences in three-digit number processing. |
Akram Bakkour; Christina Leuker; Ashleigh M. Hover; Nathan Giles; Russell A. Poldrack; Tom Schonberg Mechanisms of choice behavior shift using cue-approach training Journal Article In: Frontiers in Psychology, vol. 7, pp. 421, 2016. @article{Bakkour2016, Cue-approach training has been shown to effectively shift choices for snack food items by associating a cued button-press motor response to particular food items. Furthermore, attention is biased toward previously cued items, even when the cued item is not chosen for real consumption during a choice phase. However, the exact mechanism by which preferences shift during cue-approach training is not entirely clear. In three experiments, we shed light on the possible underlying mechanisms at play during this novel paradigm: 1) Uncued, wholly predictable motor responses paired with particular food items were not sufficient to elicit a preference shift; 2) Cueing motor responses early – concurrently with food item onset – and thus eliminating the need for heightened top-down attention to the food stimulus in preparation for a motor response also eliminated the shift in food preferences. This finding reinforces our hypothesis that heightened attention at behaviorally relevant points in time is key to changing choice behavior in the cue-approach task; 3) Crucially, indicating choice using eye movements rather than manual button presses preserves the effect, thus demonstrating that the shift in preferences is not governed by a learned motor response but more likely via modulation of subjective value in higher associative regions, consistent with previous neuroimaging results. Cue-approach training drives attention at behaviorally relevant points in time to modulate the subjective value of individual items, providing a mechanism for behavior change that does not rely on external reinforcement and that holds great promise for developing real world behavioral interventions. |
Anjuli L. A. Barber; Dania Randi; Corsin A. Muller; Ludwig Huber The processing of human emotional faces by pet and lab dogs: Evidence for lateralization and experience effects Journal Article In: PLoS ONE, vol. 11, no. 4, pp. e0152393, 2016. @article{Barber2016, From all non-human animals dogs are very likely the best decoders of human behavior. In addition to a high sensitivity to human attentive status and to ostensive cues, they are able to distinguish between individual human faces and even between human facial expressions. However, so far little is known about how they process human faces and to what extent this is influenced by experience. Here we present an eye-tracking study with dogs emanating from two different living environments and varying experience with humans: pet and lab dogs. The dogs were shown pictures of familiar and unfamiliar human faces expressing four different emotions. The results, extracted from several different eye-tracking measurements, revealed pronounced differences in the face processing of pet and lab dogs, thus indicating an influence of the amount of exposure to humans. In addition, there was some evidence for the influences of both, the familiarity and the emotional expression of the face, and strong evidence for a left gaze bias. These findings, together with recent evidence for the dog's ability to discriminate human facial expressions, indicate that dogs are sensitive to some emotions expressed in human faces. |
Adrienne E. Barnes; Young-Suk Kim Low-skilled adult readers look like typically developing child readers: A comparison of reading skills and eye movement behavior Journal Article In: Reading and Writing, vol. 29, no. 9, pp. 1889–1914, 2016. @article{Barnes2016, The paper documents 41 European case histories that describe the seismogenic response of crystalline and sedimentary rocks to fluid injection. It is part of an on-going study to identify factors that have a bearing on the seismic hazard associated with fluid injection. The data generally support the view that injection in sedimentary rocks tends to be less seismogenic than in crystalline rocks. In both cases, the presence of faults near the wells that allow pressures to penetrate significant distances vertically and laterally can be expected to increase the risk of producing felt events. All cases of injection into crystalline rocks produce seismic events, albeit usually of non-damaging magnitudes, and all crystalline rock masses were found to be critically stressed, regardless of the strength of their seismogenic responses to injection. Thus, these data suggest that criticality of stress, whilst a necessary condition for producing earthquakes that would disturb (or be felt by) the local population, is not a sufficient condition. The data considered here are not fully consistent with the concept that injection into deeper crystalline formations tends to produce larger magnitude events. The data are too few to evaluate the combined effect of depth and injected fluid volume on the size of the largest events. Injection at sites with low natural seismicity, defined by the expectation that the local peak ground acceleration has less than a 10% chance of exceeding 0.07 g in 50 years, has not produced felt events. Although the database is limited, this suggests that low natural seismicity, corresponding to hazard levels at or below 0.07 g, may be a useful indicator of a low propensity for fluid injection to produce felt or damaging events. However, higher values do not necessarily imply a high propensity. |
Pablo A. Barrionuevo; Dingcai Cao Luminance and chromatic signals interact differently with melanopsin activation to control the pupil light response Journal Article In: Journal of Vision, vol. 16, no. 11, pp. 29, 2016. @article{Barrionuevo2016, Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin. These cells receive afferent inputs from rods and cones, which provide inputs to the postreceptoral visual pathways. It is unknown, however, how melanopsin activation is integrated with postreceptoral signals to control the pupillary light reflex. This study reports human flicker pupillary responses measured using stimuli generated with a five-primary photostimulator that selectively modulated melanopsin, rod, S-, M-, and L-cone excitations in isolation, or in combination to produce postreceptoral signals. We first analyzed the light adaptation behavior of melanopsin activation and rod and cones signals. Second, we determined how melanopsin is integrated with postreceptoral signals by testing with cone luminance, chromatic blue-yellow, and chromatic red-green stimuli that were processed by magnocellular (MC), koniocellular (KC), and parvocellular (PC) pathways, respectively. A combined rod and melanopsin response was also measured. The relative phase of the postreceptoral signals was varied with respect to the melanopsin phase. The results showed that light adaptation behavior for all conditions was weaker than typical Weber adaptation. Melanopsin activation combined linearly with luminance, S-cone, and rod inputs, suggesting the locus of integration with MC and KC signals was retinal. The melanopsin contribution to phasic pupil responses was lower than luminance contributions, but much higher than S-cone contributions. Chromatic red-green modulation interacted with melanopsin activation nonlinearly as described by a "winner-takes-all" process, suggesting the integration with PC signals might be mediated by a postretinal site. |
Tom J. Barry; Bram Vervliet; Dirk Hermans Threat‐related gaze fixation and its relationship with the speed and generalisability of extinction learning Journal Article In: Australian Journal of Psychology, vol. 68, no. 3, pp. 200–208, 2016. @article{Barry2016, Objective: Attention plays an important role in the treatment of anxiety. Research has yet to elucidate how individual differences in attention or, particularly, gaze fixation can influence learning during treatment. The present investigation used an experimental analogue of the acquisition, treatment, and relapse of fear to examine this issue. Method: After pairing a stimulus (A) with an aversive electrocutaneous shock, such that participants come to fear this previously neutral stimulus, participants are repeatedly presented with a second stimulus (B) that possessed some common features with A as well as some of its own unique features. During presentations of B, fear was expected to reduce or extinguish. After this, participants were presented with C, which possessed some features of A that were not present in B as well as some features of B that were not present in A, and return of fear was assessed. Throughout this procedure, differences in gaze were measured so that this could be compared with indices for extinction and return of fear. Fear was measured in terms of skin conductance response. Results: Participants who spent more time looking at the unique features of B or who avoided the features in common with A showed slower extinction of their fear response. The same participants also showed reduced return of fear when C was presented. Conclusions: These findings are interpreted in terms of how attentional avoidance of threat-related stimuli might influence the inhibitory learning that takes place during extinction in experimental settings and exposure in clinical settings. |
Joseph E. Barton; Valentina Graci; Charlene Hafer-Macko; John D. Sorkin; Richard F. Macko Dynamic balanced reach: A temporal and spectral analysis across increasing performance demands Journal Article In: Journal of Biomechanical Engineering, vol. 138, pp. 1–13, 2016. @article{Barton2016a, Standing balanced reach is a fundamental task involved in many activities of daily living that has not been well analyzed quantitatively to assess and characterize the multiseg- mental nature of the body's movements. We developed a dynamic balanced reach test (BRT) to analyze performance in this activity; in which a standing subject is required to maintain balance while reaching and pointing to a target disk moving across a large pro- jection screen according to a sum-of-sines function. This tracking and balance task is made progressively more difficult by increasing the disk's overall excursion amplitude. Using kinematic and ground reaction force data from 32 young healthy subjects, we investigated how the motions ofthe tracking finger and whole-body center ofmass (CoM) varied in response to the motion ofthe disk across five overall disk excursion amplitudes. Group representative performance statistics for the cohort revealed a monotonically increasing root mean squared (RMS) tracking error (RMSE) and RMS deviation (RMSD) between whole-body CoM (projected onto the ground plane) and the center ofthe base of support (BoS) with increasing amplitude (p<0.03). Tracking and CoM response delays remained constant, however, at 0.5 s and 1.0 s, respectively. We also performed detailed spectral analyses ofgroup-representative response data for each ofthe five overall excur- sion amplitudes. We derived empirical and analytical transfer functions between the motion of the disk and that of the tracking finger and CoM, computed tracking and CoM responses to a step input, and RMSE and RMSD as functions ofdisk frequency. We found that for frequencies less than 1.0 Hz, RMSE generally decreased, while RMSE normalized to disk motion amplitude generally increased. RMSD, on the other hand, decreased monotonically. These findings quantitatively characterize the amplitude- and frequency- dependent nature ofyoung healthy tracking and balance in this task. The BRT is not sub- ject to floor or ceiling effects, overcoming an important deficiency associated with most research and clinical instruments used to assess balance. This makes a comprehensive quantification of young healthy balance performance possible. The results of such analy- ses could be used in work space design and in fall-prevention instructional materials, for both the home and work place. Young healthy performance represents “exemplar” per- formance and can also be used as a reference against which to compare the performance ofaging and other clinical populations at risk for falling. |
Joseph E. Barton; Anindo Roy; John D. Sorkin; Mark W. Rogers; Richard F. Macko An engineering model of human balance control—Part I: Biomechanical model Journal Article In: Journal of Biomechanical Engineering, vol. 138, no. 1, pp. 1–11, 2016. @article{Barton2016, We developed a balance measurement tool (the balanced reach test (BRT)) to assess standing balance while reaching and pointing to a target moving in three-dimensional space according to a sum-of-sines function. We also developed a three-dimensional, 13-segment biomechanical model to analyze performance in this task. Using kinematic and ground reaction force (GRF) data from the BRT, we performed an inverse dynamics analysis to compute the forces and torques applied at each of the joints during the course of a 90 s test. We also performed spectral analyses of each joint's force activations. We found that the joints act in a different but highly coordinated manner to accomplish the tracking task-with individual joints responding congruently to different portions of the target disk's frequency spectrum. The test and the model also identified clear differences between a young healthy subject (YHS), an older high fall risk (HFR) subject before participating in a balance training intervention; and in the older subject's performance after training (which improved to the point that his performance approached that of the young subject). This is the first phase of an effort to model the balance control system with sufficient physiological detail and complexity to accurately simulate the multisegmental control of balance during functional reach across the spectra of aging, medical, and neurological conditions that affect performance. Such a model would provide insight into the function and interaction of the biomechanical and neurophysiological elements making up this system; and system adaptations to changes in these elements' performance and capabilities. |
Vanessa Beanland; Rebecca K. Le; Jamie E. M. Byrne Object-scene relationships vary the magnitude of target prevalence effects in visual search Journal Article In: Journal of Experimental Psychology: Human Perception and Performance, vol. 42, no. 6, pp. 766–775, 2016. @article{Beanland2016, Efficiency of visual search in real-world tasks is affected by several factors, including scene context and target prevalence. Observers are more efficient at detecting target objects in congruent locations, and less efficient at detecting rare targets. Although target prevalence and placement often covary, previous research has investigated context and prevalence effects independently. We conducted 2 experiments to explore the potential interaction between scene context and target prevalence effects. In Experiment 1, we varied target prevalence (high, low) and context (congruent, incongruent), and, for congruent contexts, target location (typical, atypical). Experiment 2 focused on the interaction between target prevalence (high, low) and location (typical, atypical) for congruent contexts, and recorded observers' eye movements to examine search strategies. Observers were poorer at detecting low versus high prevalence targets; however, prevalence effects were significantly reduced for targets in typical, con-gruent locations compared with atypical or incongruent locations. Eye movement analyses in Experiment 2 revealed this was related to observers dwelling disproportionately on the most typical target locations within a scene. This suggests that a byproduct of contextual guidance within scenes is that placing targets in unexpected or atypical locations will further increase miss rates for uncommon targets, which has implications for real-world situations in which rare targets appear in unexpected locations. Although prevalence effects are robust, our results suggest potential for mitigating the negative consequences of low prevalence through targeted training that teaches observers where to focus their search. |
Yvonne Behnke How textbook design may influence learning with geography textbooks Journal Article In: Nordidactica – Journal of Humanities and Social Science Education, vol. 1, pp. 38–62, 2016. @article{Behnke2016, This paper investigates how textbook design may influence students' visual attention to graphics, photos and text in current geography textbooks. Eye tracking, a visual method of data collection and analysis, was utilised to precisely monitor students' eye movements while observing geography textbook spreads. In an exploratory study utilising random sampling, the eye movements of 20 students (secondary school students 15–17 years of age and university students 20–24 years of age) were recorded. The research entities were double- page spreads of current German geography textbooks covering an identical topic, taken from five separate textbooks. A two-stage test was developed. Each participant was given the task of first looking at the entire textbook spread to determine what was being explained on the pages. In the second stage, participants solved one of the tasks from the exercise section. Overall, each participant studied five different textbook spreads and completed five set tasks. After the eye tracking study, each participant completed a questionnaire. The results may verify textbook design as one crucial factor for successful knowledge acquisition from textbooks. Based on the eye tracking documentation, learning-related challenges posed by images and complex image-text structures in textbooks are elucidated and related to educational psychology insights and findings from visual communication and textbook analysis. |
Steven Beighley; Helene Intraub Does inversion affect boundary extension for briefly-presented views? Journal Article In: Visual Cognition, vol. 24, no. 3, pp. 252–259, 2016. @article{Beighley2016, Inverting scenes interferes with visual perception and memory on many tasks. Might scene inversion eliminate boundary extension (BE) for briefly-presented photographs? In Experiment 1, an upright or inverted photograph (133, 258, or 383 ms) was followed by a 258 ms masked interval and a test photograph showing the identical view. Test photographs were rated as “same”, “closer”,or “farther away” (5-point scale). BE was just as great for inverted as upright views at the 133 and 383 ms durations, but surprisingly was greater for inverted views at the 258 ms duration. In Experiment 2, 258-ms views yielded greater BE when the study photographs were always tested in the opposite orientation, indicating that the difference in BE was related to encoding. Results suggest that scene construction beyond the view boundaries occurs rapidly and is not impeded by scene inversion, but that changes in the relative quality of visual details available for upright and inverted views may sometimes yield increased BE for inverted scenes. |
Manabu Arai; Chie Nakamura It's harder to break a relationship when you commit long Journal Article In: PLoS ONE, vol. 11, no. 6, pp. e0156482, 2016. @article{Arai2016, Past research has produced evidence that parsing commitments strengthen over the processing of additional linguistic elements that are consistent with the commitments and undoing strong commitments takes more time than undoing weak commitments. It remains unclear, however, whether this so-called digging-in effect is exclusively due to the length of an ambiguous region or at least partly to the extra cost of processing these additional phrases. The current study addressed this issue by testing Japanese relative clause structure, where lexical content and sentence meaning were controlled for. The results showed evidence for a digging-in effect reflecting the strengthened commitment to an incorrect analysis caused by the processing of additional adjuncts. Our study provides strong support for the dynamical, self-organizing models of sentence processing but poses a problem for other models including serial two-stage models as well as frequency-based probabilistic models such as the surprisal theory. |
Iñigo Arandia-Romero; Seiji Tanabe; Jan Drugowitsch; Adam Kohn; Rubén Moreno-Bote Multiplicative and additive modulation of neuronal tuning with population activity affects encoded information Journal Article In: Neuron, vol. 89, no. 6, pp. 1305–1316, 2016. @article{ArandiaRomero2016, Numerous studies have shown that neuronal responses are modulated by stimulus properties and also by the state of the local network. However, little is known about how activity fluctuations of neuronal populations modulate the sensory tuning of cells and affect their encoded information. We found that fluctuations in ongoing and stimulus-evoked population activity in primate visual cortex modulate the tuning of neurons in a multiplicative and additive manner. While distributed on a continuum, neurons with stronger multiplicative effects tended to have less additive modulation and vice versa. The information encoded by multiplicatively modulated neurons increased with greater population activity, while that of additively modulated neurons decreased. These effects offset each other so that population activity had little effect on total information. Our results thus suggest that intrinsic activity fluctuations may act as a "traffic light" that determines which subset of neurons is most informative. |
Scott P. Ardoin; Katherine S. Binder; Tori E. Foster; Andrea M. Zawoyski Repeated versus wide reading: A randomized control design study examining the impact of fluency interventions on underlying reading behavior Journal Article In: Journal of School Psychology, vol. 59, pp. 13–38, 2016. @article{Ardoin2016, Repeated readings (RR) has garnered much attention as an evidence based intervention designed to improve all components of reading fluency (rate, accuracy, prosody, and comprehension). Despite this attention, there is not an abundance of research comparing its effectiveness to other potential interventions. The current study presents the findings from a randomized control trial study involving the assignment of 168 second grade students to a RR, wide reading (WR), or business as usual condition. Intervention students were provided with 9–10 weeks of intervention with sessions occurring four times per week. Pre- and post-testing were conducted using Woodcock-Johnson III reading achievement measures (Woodcock, McGrew, & Mather, 2001, curriculum-based measurement (CBM) probes, measures of prosody, and measures of students' eye movements when reading. Changes in fluency were also monitored using weekly CBM progress monitoring procedures. Data were collected on the amount of time students spent reading and the number of words read by students during each intervention session. Results indicate substantial gains made by students across conditions, with some measures indicating greater gains by students in the two intervention conditions. Analyses do not indicate that RR was superior to WR. In addition to expanding the RR literature, this study greatly expands research evaluating changes in reading behaviors that occur with improvements in reading fluency. Implications regarding whether schools should provide more opportunities to repeatedly practice the same text (i.e., RR) or practice a wide range of text (i.e., WR) are provided. |
Joseph Arizpe; Dwight J. Kravitz; Vincent Walsh; Galit Yovel; Chris I. Baker Differences in looking at own-and other-race faces are subtle and analysis-dependent: An account of discrepant reports Journal Article In: PLoS ONE, vol. 11, no. 2, pp. e0148253, 2016. @article{Arizpe2016, The Other-Race Effect (ORE) is the robust and well-established finding that people are generally poorer at facial recognition of individuals of another race than of their own race. Over the past four decades, much research has focused on the ORE because understanding this phenomenon is expected to elucidate fundamental face processingmechanisms and the influence of experience on such mechanisms. Several recent studies of the ORE in which the eye-movements of participants viewing own- and other-race faces were tracked have, however, reported highly conflicting results regarding the presence or absence of differential patterns of eye-movements to own- versus other-race faces. This discrepancy, of course, leads to conflicting theoretical interpretations of the perceptual basis for the ORE. Here we investigate fixation patterns to own- versus other-race (African and Chinese) faces for Caucasian participants using |
Serguei V. Astafiev; Kristina L. Zinn; Gordon L. Shulman; Maurizio Corbetta Exploring the physiological correlates of chronic mild traumatic brain injury symptoms Journal Article In: NeuroImage: Clinical, vol. 11, pp. 10–19, 2016. @article{Astafiev2016, 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. |
Natsuki Atagi; Melissa DeWolf; James W. Stigler; Scott P. Johnson The role of visual representations in college students' understanding of mathematical notation Journal Article In: Journal of Experimental Psychology: Applied, vol. 22, no. 3, pp. 295–304, 2016. @article{Atagi2016, Developing understanding of fractions involves connections between nonsymbolic visual representations and symbolic representations. Initially, teachers introduce fraction concepts with visual representations before moving to symbolic representations. Once the focus is shifted to symbolic representations, the connections between visual representations and symbolic notation are considered to be less useful, and students are rarely asked to connect symbolic notation back to visual representations. In 2 experiments, we ask whether visual representations affect understanding of symbolic notation for adults who understand symbolic notation. In a conceptual fraction comparison task (e.g., Which is larger, 5 / a or 8 / a?), participants were given comparisons paired with accurate, helpful visual representations, misleading visual representations, or no visual representations. The results show that even college students perform significantly better when accurate visuals are provided over misleading or no visuals. Further, eye-tracking data suggest that these visual representations may affect performance even when only briefly looked at. Implications for theories of fraction understanding and education are discussed. |