EyeLink Clinical and Oculomotor Eye-Tracking Publications
EyeLink clinical and oculomotor research publications up until 2021 (with some early 2022s) are listed below by year. You can search the publications using keywords such as Saccadic Adaptation, Schizophrenia, Nystagmus, etc. You can also search for individual author names, and limit searches by year (choose the year then click the search button). If we missed any EyeLink clinical or oculomotor articles, please email us!
Arunava Samaddar; Brooke S. Jackson; Christopher J. Helms; Nicole A. Lazar; Jennifer E. McDowell; Cheolwoo Park
In: Computational Statistics and Data Analysis, vol. 167, pp. 107361, 2022.
In the analysis of functional magnetic resonance imaging (fMRI) data, a common type of analysis is to compare differences across scanning sessions. A challenge to direct comparisons of this type is the low signal-to-noise ratio in fMRI data. By using the property that brain signals from a task-related experiment may exhibit a similar pattern in regions of interest across participants, a semiparametric approach under shape invariance to quantify and test the differences in sessions and groups is developed. The common function is estimated with local polynomial regression and the shape invariance model parameters are estimated using evolutionary optimization methods. The efficacy of the semi-parametric approach is demonstrated on a study of brain activation changes across two sessions associated with practice-related cognitive control. The objective of the study is to evaluate neural circuitry supporting a cognitive control task, and associated practice-related changes via acquisition of blood oxygenation level dependent (BOLD) signal collected using fMRI. By using the proposed approach, BOLD signals in multiple regions of interest for control participants and participants with schizophrenia are compared as they perform a cognitive control task (known as the antisaccade task) at two sessions, and the effects of task practice in these groups are quantified.
Pablo Oyarzo; David Preiss; Diego Cosmelli
In: Psychophysiology, pp. e13994, 2022.
Although eye movements during reading have been studied extensively, their variation due to attentional fluctuations such as spontaneous distractions is not well understood. Here we used a naturalistic reading task combined with an at- tentional sampling method to examine the effects of mind wandering— and the subsequent metacognitive awareness of its occurrence— on eye movements and pupillary dynamics. Our goal was to better understand the attentional and meta- cognitive processes involved in the initiation and termination of mind wander- ing episodes. Our results show that changes in eye behavior are consistent with underlying independent cognitive mechanisms working in tandem to sustain the attentional resources required for focused reading. In addition to changes in blink frequency, blink duration, and the number of saccades, variations in eye movements during unaware distractions point to a loss of the perceptual asym- metry that is usually observed in attentive, left- to- right reading. Also, before self- detected distractions, we observed a specific increase in pupillary diameter, indicating the likely presence of an anticipatory autonomic process that could contribute to becoming aware of the current attentional state. These findings stress the need for further research tackling the temporal structure of attentional dynamics during tasks that have a significant real- world impact.
Alessandro Piras; Aurelio Trofè; Andrea Meoni; Milena Raffi
In: Human Movement Science, vol. 81, pp. 102905, 2022.
The role of optic flow in the control of balance in persons with Parkinson's disease (PD) has yet to be studied. Since basal ganglia are understood to have a role in controlling ocular fixation, we have hypothesized that persons with PD would exhibit impaired performance in fixation tasks, i.e., altered postural balance due to the possible relationships between postural disorders and visual perception. The aim of this preliminary study was to investigate how people affected by PD respond to optic flow stimuli presented with radial expanding motion, with the intention to see how the stimulation of different retinal portions may alter the static postural sway. We measured the body sway using center of pressure parameters recorded from two force platforms during the presentation of the foveal, peripheral and full field radial optic flow stimuli. Persons with PD had different visual responses in terms of fixational eye movement characteristics, with greater postural alteration in the sway area and in the medio-lateral direction than the age-matched control group. Balance impairment in the medio-lateral oscillation is often observed in persons with atypical Parkinsonism, but not in Parkinson's disease. Persons with PD are more dependent on visual feedback with respect to age-matched control subjects, and this could be due to their impaired peripheral kinesthetic feedback. Visual stimulation of standing posture would provide reliable signs in the differential diagnosis of Parkinsonism.
Olivia G. Calancie; Donald C. Brien; Jeff Huang; Brian C. Coe; Linda Booij; Sarosh Khalid-Khan; Douglas P. Munoz
In: Journal of Neuroscience, vol. 42, no. 1, pp. 69–80, 2022.
When presented with a periodic stimulus, humans spontaneously adjust their movements from reacting to predicting the timing of its arrival, but little is known about how this sensorimotor adaptation changes across development. To investigate this, we analyzed saccade behavior in 114 healthy humans (ages 6–24 years) performing the visual metronome task, who were instructed to move their eyes in time with a visual target that alternated between two known locations at a fixed rate, and we compared their behavior to per- formance in a random task, where target onsets were randomized across five interstimulus intervals (ISIs) and thus the timing of appearance was unknown. Saccades initiated before registration of the visual target, thus in anticipation of its appearance, were la- beled predictive [saccade reaction time (SRT),90ms] and saccades that were made in reaction to its appearance were labeled reac- tive (SRT.90ms). Eye-tracking behavior including saccadic metrics (e.g., peak velocity, amplitude), pupil size following saccade to target, and blink behavior all varied as a function of predicting or reacting to periodic targets. Compared with reactive saccades, pre- dictive saccades had a lower peak velocity, a hypometric amplitude, smaller pupil size, and a reduced probability of blink occurrence before target appearance. The percentage of predictive and reactive saccades changed inversely from ages 8–16, at which they reached adult-levels of behavior. Differences in predictive saccades for fast and slow target rates are interpreted by differential maturation of cerebellar-thalamic-striatal pathways.
Christoph Helmchen; Björn Machner; Andreas Sprenger; David S. Zee
Monocular patching attenuates vertical nystagmus in Wernicke's encephalopathy via release of activity in subcortical visual pathways Journal Article
In: Movement Disorders Clinical Practice, vol. 9, no. 1, pp. 107–109, 2022.
Astar Lev; Yoram Braw; Tomer Elbaum; Michael Wagner; Yuri Rassovsky
In: Journal of Attention Disorders, vol. 26, no. 2, pp. 245–255, 2022.
Objective: The use of continuous performance tests (CPTs) for assessing ADHD related cognitive impairment is ubiquitous. Novel psychophysiological measures may enhance the data that is derived from CPTs and thereby improve clinical decision-making regarding diagnosis and treatment. As part of the current study, we integrated an eye tracker with the MOXO-dCPT and assessed the utility of eye movement measures to differentiate ADHD patients and healthy controls. Method: Adult ADHD patients and gender/age-matched healthy controls performed the MOXO-dCPT while their eye movements were monitored (n = 33 per group). Results: ADHD patients spent significantly more time gazing at irrelevant regions, both on the screen and outside of it, than healthy controls. The eye movement measures showed adequate ability to classify ADHD patients. Moreover, a scale that combined eye movement measures enhanced group prediction, compared to the sole use of conventional MOXO-dCPT indices. Conclusions: Integrating an eye tracker with CPTs is a feasible way of enhancing diagnostic precision and shows initial promise for clarifying the cognitive profile of ADHD patients. Pending replication, these findings point toward a promising path for the evolution of existing CPTs.
Joel T. Martin; Annalise H. Whittaker; Stephen J. Johnston
In: European Journal of Neuroscience, vol. 44, pp. 1–22, 2022.
Baseline and task-evoked pupil measures are known to reflect the activity of the nervous system's central arousal mechanisms. With the increasing availability, affordability and flexibility of video-based eye tracking hardware, these measures may one day find practical application in real-time biobehavioral monitoring systems to assess performance or fitness for duty in tasks requiring vigilant attention. But real-world vigilance tasks are predominantly visual in their nature and most research in this area has taken place in the auditory domain. Here we explore the relationship between pupil size—both baseline and task-evoked—and behavioral performance measures in two novel vigilance tasks requiring visual target detection: 1) a traditional vigilance task involving prolonged, continuous, and uninterrupted performance (n = 28), and 2) a psychomotor vigilance task (n = 25). In both tasks, behavioral performance and task-evoked pupil responses declined as time spent on task increased, corroborating previous reports in the literature of a vigilance decrement with a corresponding reduction in task-evoked pupil measures. Also in line with previous findings, baseline pupil size did not show a consistent relationship with performance measures. We discuss our findings considering the adaptive gain theory of locus coeruleus function and question the validity of the assumption that baseline (prestimulus) pupil size and task-evoked (poststimulus) pupil measures correspond to the tonic and phasic firing modes of the LC. ### Competing Interest Statement The authors have declared no competing interest.
Alexis Cheviet; Jana Masselink; Eric Koun; Roméo Salemme; Markus Lappe; Caroline Froment-Tilikete; Denis Pélisson
In: Cerebral Cortex, pp. 1–21, 2022.
Saccadic adaptation (SA) is a cerebellar-dependent learning of motor commands (MC), which aims at preserving saccade accuracy. Since SA alters visual localization during fixation and even more so across saccades, it could also involve changes of target and/or saccade visuospatial representations, the latter (CDv) resulting from a motor-to-visual transformation (forward dynamics model) of the corollary discharge of the MC. In the present study, we investigated if, in addition to its established role in adaptive adjustment of MC, the cerebellum could contribute to the adaptation-associated perceptual changes. Transfer of backward and forward adaptation to spatial perceptual performance (during ocular fixation and trans-saccadically) was assessed in eight cerebellar patients and eight healthy volunteers. In healthy participants, both types of SA altered MC as well as internal representations of the saccade target and of the saccadic eye displacement. In patients, adaptation-related adjustments of MC and adaptation transfer to localization were strongly reduced relative to healthy participants, unraveling abnormal adaptation-related changes of target and CDv. Importantly, the estimated changes of CDv were totally abolished following forward session but mainly preserved in backward session, suggesting that an internal model ensuring trans-saccadic localization could be located in the adaptation-related cerebellar networks or in downstream networks, respectively.
Koji Kuraoka; Kae Nakamura
In: Neuroscience Research, 2022.
Studies in human subjects have revealed that autonomic responses provide objective and biologically relevant information about cognitive and affective states. Measures of autonomic responses can also be applied to studies of non-human primates, which are neuro-anatomically and physically similar to humans. Facial temperature and pupil size are measured remotely and can be applied to physiological experiments in primates, preferably in a head-fixed condition. However, detailed guidelines for the use of these measures in non-human primates is lacking. Here, we review the neuronal circuits and methodological considerations necessary for measuring and analyzing facial temperature and pupil size in non-human primates. Previous studies have shown that the modulation of these measures primarily reflects sympathetic reactions to cognitive and emotional processes, including alertness, attention, and mental effort, over different time scales. Integrated analyses of autonomic, behavioral, and neurophysiological data in primates are promising methods that reflect multiple dimensions of emotion and could potentially provide tools for understanding the mechanisms underlying neuropsychiatric disorders and vulnerabilities characterized by cognitive and affective disturbances.
Marco Esposito; Clarissa Ferrari; Claudia Fracassi; Carlo Miniussi; Debora Brignani
In: European Journal of Neuroscience, pp. 1–45, 2022.
Over the past two decades, the postulated modulatory effects of transcranial direct current stimulation (tDCS) on the human brain have been extensively investigated. However, recent concerns on reliability of tDCS effects have been raised, principally due to reduced replicability This article is protected by copyright. All rights reserved. and to interindividual variability in response to tDCS. These inconsistencies are likely due to the interplay between the level of induced cortical excitability and unaccounted structural and state-dependent functional factors. On these grounds, we aimed at verifying whether the behavioural effects induced by a common tDCS montage (F3-rSOA) were influenced by the participants' arousal levels, as part of a broader mechanism of state-dependency. Pupillary dynamics were recorded during an auditory oddball task while applying either a sham or real tDCS. The tDCS effects were evaluated as a function of subjective and physiological arousal predictors (STAI-Y State scores and pre-stimulus pupil size, respectively). We showed that prefrontal tDCS hindered task learning effects on response speed such that performance improvement occurred during sham, but not real stimulation. Moreover, both subjective and physiological arousal predictors significantly explained performance during real tDCS, with interaction effects showing performance improvement only with moderate arousal levels; likewise, pupil response was affected by real tDCS according to the ongoing levels of arousal, with reduced dilation during higher arousal trials. These findings highlight the potential role of arousal in shaping the neuromodulatory outcome, thus emphasizing a more careful interpretation of null or negative results while also encouraging more individually tailored tDCS applications based on arousal levels, especially in clinical populations.
Delia A. Gheorghe; Muriel T. N. Panouillères; Nicholas D. Walsh
In: Cerebellum and Ataxias, vol. 8, no. 1, pp. 1–11, 2021.
Background: Transcranial Direct Current Stimulation (tDCS) over the prefrontal cortex has been shown to modulate subjective, neuronal and neuroendocrine responses, particularly in the context of stress processing. However, it is currently unknown whether tDCS stimulation over other brain regions, such as the cerebellum, can similarly affect the stress response. Despite increasing evidence linking the cerebellum to stress-related processing, no studies have investigated the hormonal and behavioural effects of cerebellar tDCS. Methods: This study tested the hypothesis of a cerebellar tDCS effect on mood, behaviour and cortisol. To do this we employed a single-blind, sham-controlled design to measure performance on a cerebellar-dependent saccadic adaptation task, together with changes in cortisol output and mood, during online anodal and cathodal stimulation. Forty-five participants were included in the analysis. Stimulation groups were matched on demographic variables, potential confounding factors known to affect cortisol levels, mood and a number of personality characteristics. Results: Results showed that tDCS polarity did not affect cortisol levels or subjective mood, but did affect behaviour. Participants receiving anodal stimulation showed an 8.4% increase in saccadic adaptation, which was significantly larger compared to the cathodal group (1.6%). Conclusion: The stimulation effect on saccadic adaptation contributes to the current body of literature examining the mechanisms of cerebellar stimulation on associated function. We conclude that further studies are needed to understand whether and how cerebellar tDCS may module stress reactivity under challenge conditions.
Mikael Rubin; Michael J. Telch
In: Journal of Traumatic Stress, vol. 34, no. 1, pp. 182–189, 2021.
Posttraumatic stress disorder (PTSD) is related to dysfunctional emotional processing, thus motivating the search for physiological indices that can elucidate this process. Toward this aim, we compared pupillary response patterns in response to angry and fearful auditory stimuli among 99 adults, some with PTSD (n = 14), some trauma-exposed without PTSD (TE; n = 53), and some with no history of trauma exposure (CON; n = 32). We hypothesized that individuals with PTSD would show more pupillary response to angry and fearful auditory stimuli compared to those in the TE and CON groups. Among participants who had experienced a traumatic event, we explored the association between PTSD symptoms and pupillary response; contrary to our prediction, individuals with PTSD displayed the least pupillary response to fearful auditory stimuli compared those in the TE
Lucy L. Russell; Caroline V. Greaves; Rhian S. Convery; Jennifer Nicholas; Jason D. Warren; Diego Kaski; Jonathan D. Rohrer
In: Alzheimer's Research and Therapy, vol. 13, pp. 39, 2021.
Background: Current tasks measuring social cognition are usually ‘pen and paper' tasks, have ceiling effects and include complicated test instructions that may be difficult to understand for those with cognitive impairment. We therefore aimed to develop a set of simple, instructionless, quantitative, tasks of emotion recognition using the methodology of eye tracking, with the subsequent aim of assessing their utility in individuals with behavioural variant frontotemporal dementia (bvFTD). Methods: Using the Eyelink 1000 Plus eye tracker, 18 bvFTD and 22 controls completed tasks of simple and complex emotion recognition that involved viewing four images (one target face (simple) or pair of eyes (complex) and the others non-target) followed by a target emotion word and lastly the original four images alongside the emotion word. A dwell time change score was then calculated as the main outcome measure by subtracting the percentage dwell time for the target image before the emotion word appeared away from the percentage dwell time for the target image after the emotion word appeared. All participants also underwent a standard cognitive battery and volumetric T1-weighted magnetic resonance imaging. Results: Analysis using a mixed effects model showed that the average (standard deviation) mean dwell time change score in the target interest area was 35 (27)% for the control group compared with only 4 (18)% for the bvFTD group (p < 0.05) for the simple emotion recognition task, and 15 (26)% for the control group compared with only 2 (18)% for the bvFTD group (p < 0.05) for the complex emotion recognition task. Worse performance in the bvFTD group correlated with atrophy in the right ventromedial prefrontal and orbitofrontal cortices, brain regions previously implicated in social cognition. Conclusions: In summary, eye tracking is a viable tool for assessing social cognition in individuals with bvFTD, being well-tolerated and able to overcome some of the problems associated with standard psychometric tasks.
Anthony J. Ryals; Megan E. Kelly; Anne M. Cleary
Increased pupil dilation during tip-of-the-tongue states Journal Article
In: Consciousness and Cognition, vol. 92, pp. 103152, 2021.
Tip-of-the-tongue states (TOTs) are feelings of impending word retrieval success during a current failure to retrieve a target word. Though much is known and understood about TOT states from decades of research, research on potential psychophysiological correlates of the TOT state is still in its infancy, and existing studies point toward the involvement of neural processes that are associated with enhanced attention, motivation, and information-seeking. In the present study, we demonstrate that, during instances of target retrieval failure, TOT states are associated with greater pupillary dilation (i.e., autonomic arousal) in 91% of our sample. This is the first study to demonstrate a pupillometric correlate of the TOT experience, and this finding provides an important step toward understanding emotional attributes associated with TOT states. Mean pupil dilation also increased such that instances of target identification failure that were unaccompanied by TOT states < instances in which TOTs occurred < instances of target identification success. It is possible that TOTs reflect an intermediary state between complete target retrieval failure and full target retrieval.
Giulia C. Salgari; Geoffrey F. Potts; Joseph Schmidt; Chi C. Chan; Christopher C. Spencer; Jeffrey S. Bedwell
In: Clinical Neurophysiology, vol. 132, no. 7, pp. 1526–1536, 2021.
Objectives: Negative psychiatric symptoms are often resistant to treatments, regardless of the disorder in which they appear. One model for a cause of negative symptoms is impairment in higher-order cognition. The current study examined how particular bottom-up and top-down mechanisms of selective attention relate to severity of negative symptoms across a transdiagnostic psychiatric sample. Methods: The sample consisted of 130 participants: 25 schizophrenia-spectrum disorders, 26 bipolar disorders, 18 unipolar depression, and 61 nonpsychiatric controls. The relationships between attentional event-related potentials following rare visual targets (i.e., N1, N2b, P2a, and P3b) and severity of the negative symptom domains of anhedonia, avolition, and blunted affect were evaluated using frequentist and Bayesian analyses. Results: P3b and N2b mean amplitudes were inversely related to the Positive and Negative Syndrome Scale-Negative Symptom Factor severity score across the entire sample. Subsequent regression analyses showed a significant negative transdiagnostic relationship between P3b amplitude and blunted affect severity. Conclusions: Results indicate that negative symptoms, and particularly blunted affect, may have a stronger association with deficits in top-down mechanisms of selective attention. Significance: This suggests that people with greater severity of blunted affect, independent of diagnosis, do not allocate sufficient cognitive resources when engaging in activities requiring selective attention.
Nichole E. Scheerer; Elina Birmingham; Troy Q. Boucher; Grace Iarocci
In: PLoS ONE, vol. 16, no. 6, pp. e0250763, 2021.
This study examined involuntary capture of attention, overt attention, and stimulus valence and arousal ratings, all factors that can contribute to potential attentional biases to face and train objects in children with and without autism spectrum disorder (ASD). In the visual domain, faces are particularly captivating, and are thought to have a ‘special status' in the attentional system. Research suggests that similar attentional biases may exist for other objects of expertise (e.g. birds for bird experts), providing support for the role of exposure in attention prioritization. Autistic individuals often have circumscribed interests around certain classes of objects, such as trains, that are related to vehicles and mechanical systems. This research aimed to determine whether this propensity in autistic individuals leads to stronger attention capture by trains, and perhaps weaker attention capture by faces, than what would be expected in non-autistic children. In Experiment 1, autistic children (6–14 years old) and age- and IQ-matched non-autistic children performed a visual search task where they manually indicated whether a target butterfly appeared amongst an array of face, train, and neutral distractors while their eye-movements were tracked. Autistic children were no less susceptible to attention capture by faces than non-autistic children. Overall, for both groups, trains captured attention more strongly than face stimuli and, trains had a larger effect on overt attention to the target stimuli, relative to face distractors. In Experiment 2, a new group of children (autistic and non-autistic) rated train stimuli as more interesting and exciting than the face stimuli, with no differences between groups. These results suggest that: (1) other objects (trains) can capture attention in a similar manner as faces, in both autistic and non-autistic children (2) attention capture is driven partly by voluntary attentional processes related to personal interest or affective responses to the stimuli.
Christoph Scheffel; Sven Thomas Graupner; Anne Gärtner; Josephine Zerna; Alexander Strobel; Denise Dörfel
In: Psychophysiology, vol. 58, no. 11, pp. e13908, 2021.
Emotion regulation (ER) can be implemented by different strategies which differ in their capacity to alter emotional responding. What all strategies have in common is that cognitive control must be exercised in order to implement them. The aim of the present preregistered study was to investigate whether the two ER strategies, expressive suppression and distancing, require different amounts of cognitive effort and whether effort is associated with personality traits. Effort was assessed subjectively via ratings and objectively via pupillometry and heart period. In two studies
Elena Selezneva; Michael Brosch; Sanchit Rathi; T. Vighneshvel; Nicole Wetzel
In: Frontiers in Psychology, vol. 12, pp. 754604, 2021.
Pupil dilation in response to unexpected stimuli has been well documented in human as well as in non-human primates; however, this phenomenon has not been systematically compared between the species. This analogy is also crucial for the role of non-human primates as an animal model to investigate neural mechanisms underlying the processing of unexpected stimuli and their evoked pupil dilation response. To assess this qualitatively, we used an auditory oddball paradigm in which we presented subjects a sequence of the same sounds followed by occasional deviants while we measured their evoked pupil dilation response (PDR). We used deviants (a frequency deviant, a pink noise burst, a monkey vocalization and a whistle sound) which differed in the spectral composition and in their ability to induce arousal from the standard. Most deviants elicited a significant pupil dilation in both species with decreased peak latency and increased peak amplitude in monkeys compared to humans. A temporal Principal Component Analysis (PCA) revealed two components underlying the PDRs in both species. The early component is likely associated to the parasympathetic nervous system and the late component to the sympathetic nervous system, respectively. Taken together, the present study demonstrates a qualitative similarity between PDRs to unexpected auditory stimuli in macaque and human subjects suggesting that macaques can be a suitable model for investigating the neuronal bases of pupil dilation. However, the quantitative differences in PDRs between species need to be investigated in further comparative studies.
A. Sfärlea; K. Takano; C. Buhl; J. Loechner; E. Greimel; E. Salemink; G. Schulte-Körne; B. Platt
In: Research on Child and Adolescent Psychopathology, vol. 49, no. 10, pp. 1345–1358, 2021.
Contemporary cognitive models of depression propose that cognitive biases for negative information at the level of attention (attention biases; AB) and interpretation (interpretation biases; IB) increase depression risk by promoting maladaptive emotion regulation (ER). So far, empirical support testing interactions between these variables is restricted to non-clinical and clinical adult samples. The aim of the current study was to extend these findings to a sample of children and adolescents. This cross-sectional study included 109 children aged 9–14 years who completed behavioural measures of AB (passive-viewing task) and IB (scrambled sentences task) as well as self-report measures of ER and depressive symptoms. In order to maximize the variance in these outcomes we included participants with a clinical diagnosis of depression as well as non-depressed youth with an elevated familial risk of depression and non-depressed youth with a low familial risk of depression. Path model analysis indicated that all variables (AB, IB, adaptive and maladaptive ER) had a direct effect on depressive symptoms. IB and AB also had significant indirect effects on depressive symptoms via maladaptive and adaptive ER. These findings provide initial support for the role of ER as a mediator between cognitive biases and depressive symptoms and provide the foundations for future experimental and longitudinal studies. In contrast to studies in adult samples, both adaptive as well as maladaptive ER mediated the effect of cognitive biases on depressive symptoms. This suggests potentially developmental differences in the role of ER across the lifespan.
Anca Sfärlea; Linda Lukas; Gerd Schulte-Körne; Belinda Platt
In: Journal of Eating Disorders, vol. 9, no. 1, pp. 139, 2021.
Background: Anorexia nervosa (AN) is characterized by dysfunctional cognitions including cognitive biases at various levels of information processing. However, less is known about the specificity of these biases, i.e., if they occur for eating-disorder-related information alone or also for non-eating-disorder-related emotional information in AN patients (content-specificity) and if they are unique to individuals with AN or are also shown by individuals with other mental disorders (disorder-specificity). Methods: The present study systematically assesses cognitive biases in 12–18-year-old female adolescents with AN on three levels of information processing (attention, interpretation, and memory) and with regard to two types of information content (eating-disorder-related, i.e., stimuli related to body weight and shape, and non-eating-disorder-related). To address not only content- but also disorder-specificity, adolescents with AN will be compared not only to a healthy control group but also to a clinical control group (adolescents with major depression or particular anxiety disorders). Cognitive biases are assessed within a single experimental paradigm based on the Scrambled Sentences Task. During the task eye movements are recorded in order to assess attention biases while interpretation biases are derived from the behavioural outcome. An incidental free recall test afterwards assesses memory biases. We expect adolescents with AN to show more pronounced negative cognitive biases on all three levels of information processing and for both types of content compared to healthy adolescents. In addition, we expect the specificity of biases to translate into differential results for the two types of content: AN patients are expected to show stronger biases for disorder-related stimuli but similar or less pronounced biases for non-disorder-related stimuli compared to the clinical control group. Discussion: This is the first study to comprehensively assess cognitive biases in adolescents with AN. It will have essential implications not only for cognitive-behavioural models of AN but also for subsequent studies aiming to modify cognitive biases in this population, thereby addressing important maintaining factors already at an early stage of the disorder.
Omer Sharon; Firas Fahoum; Yuval Nir
In: Journal of Neuroscience, vol. 41, no. 2, pp. 320–330, 2021.
Vagus nerve stimulation (VNS) is widely used to treat drug-resistant epilepsy and depression. While the precise mechanisms mediating its long-term therapeutic effects are not fully resolved, they likely involve locus coeruleus (LC) stimulation via the nucleus of the solitary tract, which receives afferent vagal inputs. In rats, VNS elevates LC firing and forebrain noradrenaline levels, whereas LC lesions suppress VNS therapeutic efficacy. Noninvasive transcutaneous VNS (tVNS) uses electrical stimulation that targets the auricular branch of the vagus nerve at the cymba conchae of the ear. However, the extent to which tVNS mimics VNS remains unclear. Here, we investigated the short-term effects of tVNS in healthy human male volunteers (n = 24), using high-density EEG and pupillometry during visual fixation at rest. We compared short (3.4 s) trials of tVNS to sham electrical stimulation at the earlobe (far from the vagus nerve branch) to control for somatosensory stimulation. Although tVNS and sham stimulation did not differ in subjective intensity ratings, tVNS led to robust pupil dilation (peaking 4-5 s after trial onset) that was significantly higher than following sham stimulation. We further quantified, using parallel factor analysis, how tVNS modulates idle occipital alpha (8-13Hz) activity identified in each participant. We found greater attenuation of alpha oscillations by tVNS than by sham stimulation. This demonstrates that tVNS reliably induces pupillary and EEG markers of arousal beyond the effects of somatosensory stimulation, thus supporting the hypothesis that tVNS elevates noradrenaline and other arousal-promoting neuromodulatory signaling, and mimics invasive VNS.
Adi Shechter; David L. Share
In: Psychological Science, vol. 32, no. 1, pp. 80–95, 2021.
Rapid and seemingly effortless word recognition is a virtually unquestioned characteristic of skilled reading, yet the definition and operationalization of the concept of cognitive effort have proven elusive. We investigated the cognitive effort involved in oral and silent word reading using pupillometry among adults (Experiment 1
In: JASA Express Letters, vol. 1, no. 11, pp. 115202, 2021.
Dynamic pitch, also known as intonation, conveys both semantic and pragmatic meaning in speech communica- tion. While alteration of this cue is detrimental to speech intelligibility in noise, the mechanism involved is poorly understood. Using the psychophysiological measure of task-evoked pupillary response, this study examined the perceptual effect of altered dynamic pitch cues on speech perception in noise. The data showed that pupil dilation increased with dynamic pitch strength in a sentence recognition in noise task. Taken together with recognition accuracy data, the results suggest the involvement of perceptual arousal in speech perception with dynamic pitch alteration
Les Sikos; Katharina Stein; Maria Staudte
In: Frontiers in Psychology, vol. 12, pp. 661898, 2021.
Recent work has shown that linguistic and visual contexts jointly modulate linguistic expectancy and, thus, the processing effort for a (more or less) expected critical word. According to these findings, uncertainty about the upcoming referent in a visually-situated sentence can be reduced by exploiting the selectional restrictions of a preceding word (e.g., a verb or an adjective), which then reduces processing effort on the critical word (e.g., a referential noun). Interestingly, however, no such modulation was observed in these studies on the expectation-generating word itself. The goal of the current study is to investigate whether the reduction of uncertainty (i.e., the generation of expectations) simply does not modulate processing effort-or whether the particular subject-verb-object (SVO) sentence structure used in these studies (which emphasizes the referential nature of the noun as direct pointer to visually co-present objects) accounts for the observed pattern. To test these questions, the current design reverses the functional roles of nouns and verbs by using sentence constructions in which the noun reduces uncertainty about upcoming verbs, and the verb provides the disambiguating and reference-resolving piece of information. Experiment 1 (a Visual World Paradigm study) and Experiment 2 (a Grammaticality Maze study) both replicate the effect found in previous work (i.e., the effect of visually-situated context on the word which uniquely identifies the referent), albeit on the verb in the current study. Results on the noun, where uncertainty is reduced and expectations are generated in the current design, were mixed and were most likely influenced by design decisions specific to each experiment. These results show that processing of the reference-resolving word—whether it be a noun or a verb—reliably benefits from the prior linguistic and visual information that lead to the generation of concrete expectations.
Jack W. Silcox; Brennan R. Payne
In: Cortex, vol. 142, pp. 296–316, 2021.
There is an apparent disparity between the fields of cognitive audiology and cognitive electrophysiology as to how linguistic context is used when listening to perceptually challenging speech. To gain a clearer picture of how listening effort impacts context use, we conducted a pre-registered study to simultaneously examine electrophysiological, pupillometric, and behavioral responses when listening to sentences varying in contextual constraint and acoustic challenge in the same sample. Participants (N = 44) listened to sentences that were highly constraining and completed with expected or unexpected sentence-final words (“The prisoners were planning their escape/party”) or were low-constraint sentences with unexpected sentence-final words (“All day she thought about the party”). Sentences were presented either in quiet or with +3 dB SNR background noise. Pupillometry and EEG were simultaneously recorded and subsequent sentence recognition and word recall were measured. While the N400 expectancy effect was diminished by noise, suggesting impaired real-time context use, we simultaneously observed a beneficial effect of constraint on subsequent recognition memory for degraded speech. Importantly, analyses of trial-to-trial coupling between pupil dilation and N400 amplitude showed that when participants' showed increased listening effort (i.e., greater pupil dilation), there was a subsequent recovery of the N400 effect, but at the same time, higher effort was related to poorer subsequent sentence recognition and word recall. Collectively, these findings suggest divergent effects of acoustic challenge and listening effort on context use: while noise impairs the rapid use of context to facilitate lexical semantic processing in general, this negative effect is attenuated when listeners show increased effort in response to noise. However, this effort-induced reliance on context for online word processing comes at the cost of poorer subsequent memory.
Ian Skinner; Markus Hübscher; Hopin Lee; Adrian C. Traeger; G. Lorimer Moseley; Benedict M. Wand; Sylvia M. Gustin; James H. McAuley
In: Scandinavian Journal of Pain, vol. 21, no. 3, pp. 485–494, 2021.
It has been hypothesised that attentional bias to environmental threats can contribute to persistent pain. It is unclear whether people with acute low back pain (LBP) have an attentional bias to environmental threats. We investigated if attentional bias of threat related words is different in people with acute LBP and pain-free controls. People with acute LBP and pain-free people completed a free viewing eye tracking task. Participants were simultaneously presented with two words, a threat related word and a neutral control word. Threat related words were general threat, affective pain and sensory pain. We conducted linear mixed models to detect differences between acute LBP and pain-free participants on five eye tracking outcome measures (dwell time, first fixation, latency to first fixation, first run dwell time and number of fixations). We calculated absolute reliability, (standard error of measure), and relative reliability (intraclass correlation coefficients [ICC 2,1]) for each eye tracking outcome measures. We recruited 65 people with acute LBP and 65 pain-free controls. Participants with acute LBP had a higher proportion of fixations towards the affective pain words (M=0.5009, 95% CI=0.4941, 0.5076) than the pain-free controls had (M=0.4908, 95% CI=0.4836, 0.4979), mean between group difference = -0.0101, 95% CI [-0.0198, -0.0004]
Emma J. Solly; Meaghan Clough; Allison M. McKendrick; Paige Foletta; Owen B. White; Joanne Fielding
In: Scientific Reports, vol. 11, pp. 9607, 2021.
Visual snow syndrome (VSS) is a poorly understood neurological disorder that features a range of disabling sensory changes. Visual processing changes revealed previously in VSS appear consistent with poor attentional control, specifically, with difficulty controlling environmentally driven shifts of attention. This study sought to confirm this proposal by determining whether these changes were similarly evident where attention is internally driven. Sixty seven VSS patients and 37 controls completed two saccade tasks: the endogenously cued saccade task and saccadic Simon task. The endogenously cued saccade task correctly (valid trial) or incorrectly (invalid trial) pre-cues a target location using a centrally presented arrow. VSS patients generated significantly shorter saccade latencies for valid trials (p = 0.03), resulting in a greater magnitude cue effect (p = 0.02), i.e. the difference in latency between valid and invalid trials. The saccadic Simon task presents a peripheral cue which may be spatially congruent or incongruent with the subsequent target location. Latencies on this task were comparable for VSS patients and controls, with a normal Simon effect, i.e. shorter latencies for saccades to targets spatially congruent with the preceding cue. On both tasks, VSS patients generated more erroneous saccades than controls towards non-target locations (Endogenously cued saccade task: p = 0.02, saccadic Simon task: p = 0.04). These results demonstrate that cued shifts of attention differentially affect saccade generation in VSS patients. We propose that these changes are not due to impairment of frontally-mediated inhibitory control, but to heightened saccade-related activity in visual regions. These results contribute to a VSS ocular motor signature that may provide clinical utility as well as an objective measure of dysfunction to facilitate future research.
Marianna Stella; Paul E. Engelhardt
In: Brain Sciences, vol. 11, pp. 915, 2021.
In this study, we examined eye movements and comprehension in sentences containing a relative clause. To date, few studies have focused on syntactic processing in dyslexia and so one goal of the study is to contribute to this gap in the experimental literature. A second goal is to contribute to theoretical psycholinguistic debate concerning the cause and the location of the processing difficulty associated with object-relative clauses. We compared dyslexic readers (n = 50) to a group of non-dyslexic controls (n = 50). We also assessed two key individual differences variables (working memory and verbal intelligence), which have been theorised to impact reading times and comprehension of subject-and object-relative clauses. The results showed that dyslexics and controls had similar comprehension accuracy. However, reading times showed participants with dyslexia spent significantly longer reading the sentences compared to controls (i.e., a main effect of dyslexia). In general, sentence type did not interact with dyslexia status. With respect to individual differences and the theoretical debate, we found that processing difficulty between the subject and object relatives was no longer significant when individual differences in working memory were controlled. Thus, our findings support theories, which assume that working memory demands are responsible for the processing difficulty incurred by (1) individuals with dyslexia and (2) object-relative clauses as compared to subject relative clauses.
Georgia F Symons; Meaghan Clough; Steven Mutimer; Brendan P Major; William T O'Brien; Daniel Costello; Stuart J McDonald; Zhibin Chen; Owen White; Richelle Mychasiuk; Meng Law; David K Wright; Terence J O'Brien; Joanne Fielding; Scott C Kolbe; Sandy R Shultz
In: Brain Communications, vol. 3, no. 3, pp. 1–12, 2021.
A history of concussion has been linked to long-term cognitive deficits; however, the neural underpinnings of these abnormalities are poorly understood. This study recruited 26 asymptomatic male Australian footballers with a remote history of concussion (i.e. at least six months since last concussion), and 23 non-collision sport athlete controls with no history of concussion. Participants completed three ocular motor tasks (prosaccade, antisaccade and a cognitively complex switch task) to assess processing speed, inhibitory control and cognitive flexibility, respectively. Diffusion tensor imaging data were acquired using a 3 T MRI scanner, and analysed using tract-based spatial statistics, to investigate white matter abnormalities and how they relate to ocular motor performance. Australian footballers had significantly slower adjusted antisaccade latencies compared to controls (P = 0.035). A significant switch cost (i.e. switch trial error > repeat trial error) was also found on the switch task, with Australian footballers performing increased magnitude of errors on prosaccade switch trials relative to prosaccade repeat trials (P = 0.023). Diffusion tensor imaging analysis found decreased fractional anisotropy, a marker of white matter damage, in major white matter tracts (i.e. corpus callosum, corticospinal tract) in Australian footballers relative to controls. Notably, a larger prosaccade switch cost was significantly related to reduced fractional anisotropy in anterior white matter regions found to connect to the prefrontal cortex (i.e. a key cortical ocular motor centre involved in executive functioning and task switching). Taken together, Australian footballers with a history of concussion have ocular motor deficits indicative of poorer cognitive processing speed and cognitive flexibility, which are related to reduce white matter integrity in regions projecting to important cognitive ocular motor structures. These findings provide novel insights into the neural mechanisms that may underly chronic cognitive impairments in individuals with a history of concussion.
Vijay K Tailor; Tessa M Dekker; John A Greenwood; Maria Theodorou; Annegret H. Dahlmann- Noor; Tessa M Dekker; John A Greenwood
In: Journal of Vision, vol. 21, no. 13, pp. 1–23, 2021.
Idiopathic infantile nystagmus syndrome is a disorder characterised by involuntary eye movements, which leads to decreased acuity and visual function. One such function is visual crowding – a process whereby objects that are easily recognised in isolation become impaired by nearby flankers. Crowding typically occurs in the peripheral visual field, although elevations in foveal vision have been reported in congenital nystagmus, similar to those found with amblyopia. Here, we examine whether elevated foveal crowding with nystagmus is driven by similar mechanisms to those of amblyopia – long-term neural changes associated with a sensory deficit – or by the momentary displacement of the stimulus through nystagmus eye movements. A Landolt-C orientation identification task was used to measure threshold gap sizes with and without either horizontally or vertically placed Landolt-C flankers. We assume that a sensory deficit should give equivalent crowding in these two dimensions, whereas an origin in eye movements should give stronger crowding with horizontal flankers given the predominantly horizontal eye movements of nystagmus. We observe elevations in nystagmic crowding that are above crowding in typical vision but below that of amblyopia. Consistent with an origin in eye movements, elevations were stronger with horizontal than vertical flankers in nystagmus, but not in typical or amblyopic vision. We further demonstrate the same horizontal elongation in typical vision with stimulus movement that simulates nystagmus. Consequently, we propose that the origin of nystagmic crowding lies in the eye movements, either through image smear of the target and flanker elements or through relocation of the stimulus into the peripheral retina.
Anthony Tapper; David Gonzalez; Mina Nouredanesh; Ewa Niechwiej-Szwedo
Pupillometry provides a psychophysiological index of arousal level and cognitive effort during the performance of a visual-auditory dual-task in individuals with a history of concussion Journal Article
In: Vision Research, vol. 184, pp. 43–51, 2021.
Research shows that concussions cause long-term deficits in executive functions when tested using challenging tasks with high cognitive load. The neurophysiological mechanism(s) associated with executive dysfunction are not well understood. Pupillometry provides a non-invasive index of arousal and cognitive load; therefore, the current study investigated whether pupillometry could help explain the persistent deficits in dual-task performance in individuals with a history of concussion (n = 14) compared to controls (n = 13). Participants were tested using a computerized Corsi block task which increased in difficulty as a function of set size (i.e., number of blocks to be remembered) and task condition (i.e., performed alone and concurrently with an auditory task). Pupil size was measured during the initial fixation prior to the Corsi task to assess arousal level, and during the encoding phase to assess task evoked pupil response. Results showed that: 1) in contrast to the control group, pupil size was not modulated by task condition in the concussed group indicating that arousal level was similar in the single and dual task; 2) task evoked pupil dilation increased as a function of set size in the single task in both groups, 3) in contrast to the control group, those with a history of concussion had similar pupil size during the single and dual task conditions. One interpretation of these results is that individuals with a history of concussion exert greater effort when performing relatively easier tasks, and they reach capacity limits when the cognitive load is lower in comparison to non-concussed individuals. In conclusion, pupillometry may provide insight into persisting deficits in executive functions following concussion(s).
Nathan Tardiff; John D. Medaglia; Danielle S. Bassett; Sharon L. Thompson-Schill
In: NeuroImage, vol. 240, pp. 118369, 2021.
There is growing interest in how neuromodulators shape brain networks. Recent neuroimaging studies provide evidence that brainstem arousal systems, such as the locus coeruleus-norepinephrine system (LC-NE), influence functional connectivity and brain network topology, suggesting they have a role in flexibly reconfiguring brain networks in order to adapt behavior and cognition to environmental demands. To date, however, the relationship between brainstem arousal systems and functional connectivity has not been assessed within the context of a task with an established relationship between arousal and behavior, with most prior studies relying on incidental variations in arousal or pharmacological manipulation and static brain networks constructed over long periods of time. These factors have likely contributed to a heterogeneity of effects across studies. To address these issues, we took advantage of the association between LC-NE-linked arousal and exploration to probe the relationships between exploratory choice, arousal—as measured indirectly via pupil diameter—and brain network dynamics. Exploration in a bandit task was associated with a shift toward fewer, more weakly connected modules that were more segregated in terms of connectivity and topology but more integrated with respect to the diversity of cognitive systems represented in each module. Functional connectivity strength decreased, and changes in connectivity were correlated with changes in pupil diameter, in line with the hypothesis that brainstem arousal systems influence the dynamic reorganization of brain networks. More broadly, we argue that carefully aligning dynamic network analyses with task designs can increase the temporal resolution at which behaviorally- and cognitively-relevant modulations can be identified, and offer these results as a proof of concept of this approach.
Katharine N. Thakkar; Livon Ghermezi; Steven M. Silverstein; Rachael Slate; Beier Yao; Eric D. Achtyes; Jan W. Brascamp
Stronger tilt aftereffects in persons with schizophrenia Journal Article
In: Journal of abnormal psychology, vol. 130, no. 2, pp. 186–197, 2021.
Individuals with schizophrenia may fail to appropriately use temporal context and apply past environmental regularities to the interpretation of incoming sensory information. Here we use the visual system as a test bed for investigating how prior experience shapes perception in individuals with schizophrenia. Specifically, we use visual aftereffects, illusory percepts resulting from prior exposure to visual input, to measure the influence of prior events on current processing. At a neural level, visual aftereffects arise due to attenuation in the responses of neurons that code the features of the prior stimulus (neuronal adaptation) and subsequent disinhibition of neurons signaling activity at the opposite end of the feature dimension. In the current study, we measured tilt aftereffects and negative afterimages, 2 types of aftereffects that reflect, respectively, adaptation of cortical orientation-coding neurons and adaptation of subcortical and retinal luminance-coding cells in persons with schizophrenia (PSZ; n = 36) and demographically matched healthy controls (HC; n = 22). We observed stronger tilt aftereffects in PSZ compared to HC, but no difference in negative afterimages. Stronger tilt aftereffects were related to more severe negative symptoms. These data suggest oversensitivity to recent regularities, in the form of stronger visual adaptation, at cortical, but not subcortical, levels in schizophrenia. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
Bao N. Nguyen; Scott C. Kolbe; Ashika Verghese; Christine Nearchou; Allison M. McKendrick; Gary F. Egan; Trichur R. Vidyasagar
In: Neuropsychologia, vol. 155, pp. 107819, 2021.
Dyslexia is characterised by poor reading ability. Its aetiology is probably multifactorial, with abnormal visual processing playing an important role. Among adults with normal reading ability, there is a larger representation of central visual field in the primary visual cortex (V1) in those with more efficient visuospatial attention. In this study, we tested the hypothesis that poor reading ability in school-aged children (17 children with dyslexia, 14 control children with normal reading ability) is associated with deficits in visuospatial attention using a visual search task. We corroborated the psychophysical findings with neuroimaging, by measuring the functional size of V1 in response to a central 12° visual stimulus. Consistent with other literature, visual search was impaired and less efficient in the dyslexic children, particularly with more distractor elements in the search array (p = 0.04). We also found atypical interhemispheric asymmetry in functional V1 size in the dyslexia group (p = 0.02). Reading impaired children showed poorer visual search efficiency (p = 0.01), needing more time per unit distractor (higher ms/item). Reading ability was also correlated with V1 size asymmetry (p = 0.03), such that poorer readers showed less left hemisphere bias relative to the right hemisphere. Our findings support the view that dyslexic children have abnormal visuospatial attention and interhemispheric V1 asymmetry, relative to chronological age-matched peers, and that these factors may contribute to inter-individual variation in reading performance in children.
J. A. Nij Bijvank; E. M. M. Strijbis; I. M. Nauta; S. D. Kulik; L. J. Balk; C. J. Stam; A. Hillebrand; J. J. G. Geurts; B. M. J. Uitdehaag; L. J. Rijn; A. Petzold; M. M. Schoonheim
In: NeuroImage: Clinical, vol. 32, pp. 102848, 2021.
Background: Impaired eye movements in multiple sclerosis (MS) are common and could represent a non-invasive and accurate measure of (dys)functioning of interconnected areas within the complex brain network. The aim of this study was to test whether altered saccadic eye movements are related to changes in functional connectivity (FC) in patients with MS. Methods: Cross-sectional eye movement (pro-saccades and anti-saccades) and magnetoencephalography (MEG) data from the Amsterdam MS cohort were included from 176 MS patients and 33 healthy controls. FC was calculated between all regions of the Brainnetome atlas in six conventional frequency bands. Cognitive function and disability were evaluated by previously validated measures. The relationships between saccadic parameters and both FC and clinical scores in MS patients were analysed using multivariate linear regression models. Results: In MS pro- and anti-saccades were abnormal compared to healthy controls A relationship of saccadic eye movements was found with FC of the oculomotor network, which was stronger for regional than global FC. In general, abnormal eye movements were related to higher delta and theta FC but lower beta FC. Strongest associations were found for pro-saccadic latency and FC of the precuneus (beta band $beta$ = -0.23
Sean R. O'Bryan; Miranda Scolari
In: Attention, Perception, and Psychophysics, vol. 83, no. 4, pp. 1491–1507, 2021.
Visual attention studies have demonstrated that the shape of space-based selection can be governed by salient object contours: when a portion of an enclosed space is cued, the selected region extends to the full enclosure. Although this form of object-based attention (OBA) is well established, one continuing investigation focuses on whether this selection is obligatory or under voluntary control. We attempt to dissociate between these alternatives by interrogating the locus coeruleus-norepinephrine (LC-NE) system – known to fluctuate with top-down attention – during a classic two-rectangle paradigm in a sample of healthy human participants (N = 36). An endogenous spatial pre-cue directed voluntary space-based attention (SBA) to one end of a rectangular frame. We manipulated the reliability of the cue, such that targets appearing at an uncued location within the frame occurred at low or moderate frequencies. Phasic pupillary responses time-locked to the cue display served to noninvasively measure LC-NE activity, reflecting top-down processing of the spatial cue. If OBA is controlled analogously to SBA, then object selection should emerge only when it is behaviorally expedient and when LC-NE activity reflects a high degree of top-down attention to the cue display. Our results bore this out. Thus, we conclude that OBA was voluntarily controlled, and furthermore show that phasic norepinephrine may modulate attentional strategy.
Julie Ouerfelli-Ethier; Romeo Salemme; Romain Fournet; Christian Urquizar; Laure Pisella; Aarlenne Z Khan
In: Cerebral Cortex Communications, vol. 2, no. 3, pp. 1–15, 2021.
Anti-saccades are eye movements that require inhibition to stop the automatic saccade to the visual target and to perform instead a saccade in the opposite direction. The inhibitory processes underlying anti-saccades have been primarily associated with frontal cortex areas for their role in executive control. Impaired performance in anti-saccades has also been associated with the parietal cortex, but its role in inhibitory processes remains unclear. Here, we tested the assumption that the dorsal parietal cortex contributes to spatial inhibition processes of contralateral visual target. We measured anti-saccade performance in 2 unilateral optic ataxia patients and 15 age-matched controls. Participants performed 90 degree (across and within visual fields) and 180 degree inversion anti-saccades, as well as pro-saccades. The main result was that our patients took longer to inhibit visually guided saccades when the visual target was presented in the ataxic hemifield and the task required a saccade across hemifields. This was observed through anti-saccades latencies and error rates. These deficits show the crucial role of the dorsal posterior parietal cortex in spatial inhibition of contralateral visual target representations to plan an accurate anti-saccade toward the ipsilesional side.
Woon Ju Park; Kimberly B. Schauder; Oh Sang Kwon; Loisa Bennetto; Duje Tadin
In: Clinical Psychological Science, vol. 9, no. 5, pp. 944–960, 2021.
A recent theory posits that prediction deficits may underlie the core symptoms in autism spectrum disorder (ASD). However, empirical evidence for this hypothesis is minimal. Using a visual extrapolation task, we tested motion-prediction abilities in children and adolescents with and without ASD. We examined the factors known to be important for motion prediction: the central-tendency response bias and smooth-pursuit eye movements. In participants with ASD, response biases followed an atypical trajectory that was dominated by early responses. This differed from control participants, who exhibited response biases that reflected a gradual accumulation of knowledge about stimulus statistics. Moreover, although better smooth-pursuit eye movements for the moving object were linked to more accurate motion prediction in control participants, in participants with ASD, better smooth pursuit was counterintuitively linked to a more pronounced early-response bias. Together, these results demonstrate atypical visual prediction abilities in people with ASD and offer insights into possible mechanisms underlying the observed differences.
Benjamin A. Parris; Nabil Hasshim; Zoltan Dienes
In: European Journal of Neuroscience, vol. 53, no. 8, pp. 2819–2834, 2021.
The mechanisms underpinning the apparently remarkable levels of cognitive and behavioural control following hypnosis and hypnotic suggestion are poorly understood. Numerous independent studies have reported that Stroop interference can be reduced following a post-hypnotic suggestion that asks participants to perceive words as if made up of characters from a foreign language. This effect indicates that frontal executive functions can be more potent than is generally accepted and has been described as resulting from top-down control not normally voluntarily available. We employed eye tracking and pupillometry to investigate whether the effect results from voluntary visuo-attentional strategies (subtly looking away from the word to prevent optimal word processing), reduced response conflict but not overall conflict, Stroop effects being pushed from response selection to response execution (response durations) or increased proactive effortful control given enhanced contextual motivation (as indexed via pupil dilation). We replicated the reduction in Stroop interference following the suggestion despite removing any trials on which eye movements were not consistent with optimal word processing. Our data were inconclusive with regards to conflict type affected by the suggestion in the latency data, although preserved semantic conflict was evident in the pupil data. There was also no evidence of Stroop effects on response durations. However, we show that baseline-corrected pupil sizes were larger following the suggestion indicating the socio-cognitive context and experimental demands motivate participants to marshal greater effortful control.
Mohsen Parto Dezfouli; Saeideh Davoudi; Robert T. Knight; Mohammad Reza Daliri; Elizabeth L. Johnson
In: Cortex, vol. 138, pp. 113–126, 2021.
How does the human brain integrate spatial and temporal information into unified mnemonic representations? Building on classic theories of feature binding, we first define the oscillatory signatures of integrating ‘where' and ‘when' information in working memory (WM) and then investigate the role of prefrontal cortex (PFC) in spatiotemporal integration. Fourteen individuals with lateral PFC damage and 20 healthy controls completed a visuospatial WM task while electroencephalography (EEG) was recorded. On each trial, two shapes were presented sequentially in a top/bottom spatial orientation. We defined EEG signatures of spatiotemporal integration by comparing the maintenance of two possible where-when configurations: the first shape presented on top and the reverse. Frontal delta-theta ($delta$$theta$; 2–7 Hz) activity, frontal-posterior $delta$$theta$ functional connectivity, lateral posterior event-related potentials, and mesial posterior alpha phase-to-gamma amplitude coupling dissociated the two configurations in controls. WM performance and frontal and mesial posterior signatures of spatiotemporal integration were diminished in PFC lesion patients, whereas lateral posterior signatures were intact. These findings reveal both PFC-dependent and independent substrates of spatiotemporal integration and link optimal performance to PFC.
Ivanna M. Pavisic; Yoni Pertzov; Jennifer M. Nicholas; Antoinette O'Connor; Kirsty Lu; Keir X. X. Yong; Masud Husain; Nick C. Fox; Sebastian J. Crutch
In: Scientific Reports, vol. 11, pp. 8696, 2021.
The basis of visual short-term memory (VSTM) impairments in preclinical Alzheimer's disease (AD) remains unclear. Research suggests that eye movements may serve as indirect surrogates to investigate VSTM. Yet, investigations in preclinical populations are lacking. Fifty-two individuals from a familial Alzheimer's disease (FAD) cohort (9 symptomatic carriers, 17 presymptomatic carriers and 26 controls) completed the “Object-localisation” VSTM task while an eye-tracker recorded eye movements during the stimulus presentation. VSTM function and oculomotor performance were compared between groups and their association during encoding investigated. Compared to controls, symptomatic FAD carriers showed eye movement patterns suggestive of an ineffective encoding and presymptomatic FAD carriers within 6 years of their expected age at symptom onset, were more reliant on the stimuli fixation time to achieve accuracy in the localisation of the target. Consequently, for shorter fixation times on the stimuli, presymptomatic carriers were less accurate at localising the target than controls. By contrast, the only deficits detected on behavioural VSTM function was in symptomatic individuals. Our findings provide novel evidence that encoding processes may be vulnerable and weakened in presymptomatic FAD carriers, most prominently for spatial memory, suggesting a possible explanation for the subtle VSTM impairments observed in the preclinical stages of AD.
M. C. Pfaltz; M. M. Plichta; C. J. Bockisch; L. Jellestad; U. Schnyder; K. Stocker
In: Psychiatry Research, vol. 299, pp. 113845, 2021.
Metaphorically, the future can be perceived as approaching us (time-moving metaphor) or as being approached by us (ego-moving metaphor). Also, in line with findings that our eyes look more up when thinking about the future than the past, the future's location can be conceptualized in upwards terms. Eye movements were recorded in 19 participants with PTSD and 20 healthy controls. Participants with PTSD showed downward and healthy controls upward eye movements while processing an ego/time-moving ambiguous phrase, suggesting a passive (time-moving) outlook toward the future. If replicated, our findings may have implications for the conceptualization and treatment of PTSD.
Ella Podvalny; Leana E. King; Biyu J. He
In: eLife, vol. 10, pp. e68265, 2021.
Arousal levels perpetually rise and fall spontaneously. How markers of arousal—pupil size and frequency content of brain activity—relate to each other and influence behavior in humans is poorly understood. We simultaneously monitored magnetoencephalography and pupil in healthy volunteers at rest and during a visual perceptual decision-making task. Spontaneously varying pupil size correlates with power of brain activity in most frequency bands across large-scale resting-state cortical networks. Pupil size recorded at prestimulus baseline correlates with subsequent shifts in detection bias (c) and sensitivity (d'). When dissociated from pupil-linked state, prestimulus spectral power of resting state networks still predicts perceptual behavior. Fast spontaneous pupil constriction and dilation correlate with large-scale brain activity as well but not perceptual behavior. Our results illuminate the relation between central and peripheral arousal markers and their respective roles in human perceptual decision-making.
Dorothee Pöhlchen; Marthe Priouret; Miriam S. Kraft; Florian P. Binder; Deniz A. Gürsel; Götz Berberich; Kathrin Koch; Victor I. Spoormaker
In: Frontiers in Psychiatry, vol. 12, pp. 730742, 2021.
Obsessive-compulsive disorder (OCD) is characterized by recurrent, persistent thoughts and repetitive behaviors causing stress and anxiety. In the associative learning model of OCD, mechanisms of fear extinction are supposed to partly underlie symptom development, maintenance and treatment of OCD, proposing that OCD patients suffer from rigid memory associations and inhibitory learning deficits. To test these assumptions, previous studies have used skin conductance and subjective ratings as readouts in fear conditioning paradigms, finding impaired fear extinction learning, impaired fear extinction recall or no differences between individuals with OCD and healthy controls. Against this heterogeneous background, we tested fear acquisition and extinction in 37 OCD patients and 56 healthy controls, employing skin conductance as well as pupillometry and startle electromyography. Extinction recall was also included in a subsample. We did not observe differences between groups in any of the task phases, except a trend toward higher startle amplitudes during extinction for OCD. Overall, sensitive readouts such as pupillometry and startle responses did not provide evidence for moderate-to-large inhibitory learning deficits using classical fear conditioning, challenging the assumption of generically impaired extinction learning and memory in OCD.
Megan Polden; Trevor J. Crawford
In: Cortex, vol. 142, pp. 169–185, 2021.
The current study investigated a novel visual distracter task as a potential diagnostic marker for the detection of cognitive impairment and the extent to which this compares in healthy ageing across two cultures. The Inhibition of a Recent Distracter Effect (IRD) refers to the inhibition of a saccadic eye movement towards a target that is presented at the location of a previous distracter. Two studies compared the IRD across a large cross-cultural sample comprising of young (N = 75), old European participants (N = 119), old south Asian participants (N = 83), participants with Dementia due to Alzheimer's disease (N = 65) and Mild cognitive impairment (N = 91). Significantly longer saccadic reaction times on the target to distracter trials, in comparison to the target to target trials were evident in all groups and age cohorts. Importantly, the IRD was also preserved in participants with Alzheimer's Disease and mild cognitive impairment demonstrating that the IRD is robust across cultures, age groups and clinical populations. Eye-tracking is increasingly used as a dual diagnostic and experimental probe for the investigation of cognitive control in Alzheimer's disease. As a promising methodology for the early diagnosis of dementia, it is important to understand the cognitive operations in relation to eye-tracking that are well preserved as well as those that are abnormal. Paradigms should also be validated across ethnicity/culture, clinical groups and age cohorts.
Brendan L. Portengen; Carlien Roelofzen; Giorgio L. Porro; Saskia M. Imhof; Alessio Fracasso; Marnix Naber
In: Vision Research, vol. 178, pp. 79–85, 2021.
The pupil can be used as an objective measure for testing sensitivities across the visual field (pupil perimetry; PP). The recently developed gaze-contingent flicker PP (gcFPP) is a promising novel form of PP, with improved sensitivity due to retinotopically stable and repeated flickering stimulations, in a short time span. As a diagnostic tool gcFPP has not yet been benchmarked in healthy individuals. The main aims of the current study were to investigate whether gcFPP has the sensitivity to detect the blind spot, and upper versus lower visual field differences that were found before in previous studies. An additional aim was to test for the effects of attentional requirements and background luminance. A total of thirty individuals were tested with gcFPP across two separate experiments. The results showed that pupil oscillation amplitudes were smaller for stimuli presented inside as compared to outside the blind spot. Amplitudes also decreased as a function of eccentricity (i.e., distance to fixation) and were larger for upper as compared to lower visual fields. We measured the strongest and most sensitive pupil responses to stimuli presented on dark- and mid-gray backgrounds, and when observers covertly focused their attention to the flickering stimulus. GcFPP thus evokes pupil responses that are sensitive enough to detect local, and global differences in pupil sensitivity. The findings further encourage (1) the use of a gray background to prevent straylight without affecting gcFPPs sensitivity and (2) the use of an attention task to enhance pupil sensitivity.
Jonathan E. Prunty; Jolie R. Keemink; David J. Kelly
In: Developmental Science, pp. 13182, 2021.
Facial expressions are one way in which infants and adults communicate emotion. Infants scan expressions similarly to adults, yet it remains unclear whether they are receptive to the affective information they convey. The current study investigates 6-, 9- and 12-month infants' (N = 146) pupillary responses to the six “basic” emotional expressions (happy, sad, surprise, fear, anger, and disgust). To do this we use dynamic stimuli and gaze-contingent eye-tracking to simulate brief interactive exchanges, alongside a static control condition. Infants' arousal responses were stronger for dynamic compared to static stimuli. And for dynamic stimuli we found that, compared to neutral, infants showed dilatory responses for happy and angry expressions only. Although previous work has shown infants can discriminate perceptually between facial expressions, our data suggest that sensitivity to the affective content of all six basic emotional expressions may not fully emerge until later in ontogeny.
Hamed Rahimi-Nasrabadi; Jianzhong Jin; Reece Mazade; Carmen Pons; Sohrab Najafian; Jose Manuel Alonso
Image luminance changes contrast sensitivity in visual cortex Journal Article
In: Cell Reports, vol. 34, no. 5, pp. 1–21, 2021.
Accurate measures of contrast sensitivity are important for evaluating visual disease progression and for navigation safety. Previous measures suggested that cortical contrast sensitivity was constant across widely different luminance ranges experienced indoors and outdoors. Against this notion, here, we show that luminance range changes contrast sensitivity in both cat and human cortex, and the changes are different for dark and light stimuli. As luminance range increases, contrast sensitivity increases more within cortical pathways signaling lights than those signaling darks. Conversely, when the luminance range is constant, light-dark differences in contrast sensitivity remain relatively constant even if background luminance changes. We show that a Naka-Rushton function modified to include luminance range and light-dark polarity accurately replicates both the statistics of light-dark features in natural scenes and the cortical responses to multiple combinations of contrast and luminance. We conclude that differences in light-dark contrast increase with luminance range and are largest in bright environments.
Matti Rantanen; Jarkko Hautala; Otto Loberg; Jaakko Nuorva; Jari K. Hietanen; Lauri Nummenmaa; Piia Astikainen
In: Scandinavian Journal of Psychology, vol. 62, no. 5, pp. 639–647, 2021.
Depressed individuals exhibit an attentional bias towards mood-congruent stimuli, yet evidence for biased processing of threat-related information in human interaction remains scarce. Here, we tested whether an attentional bias towards interpersonally aggressive pictures over interpersonally neutral pictures could be observed to a greater extent in depressed participants than in control participants. Eye movements were recorded while the participants freely viewed visually matched interpersonally aggressive and neutral pictures, which were presented in pairs. Across the groups, participants spent more time looking at neutral pictures than at aggressive pictures, probably reflecting avoidance behavior. When the participants could anticipate the stimulus valence, depressed participants – but not controls – showed an early attentional bias towards interpersonally aggressive pictures, as indexed by their longer first fixation durations on aggressive pictures than on neutral pictures. Our results thus preliminarily suggest both an early attentional bias towards interpersonal aggression, which is present, in depressed participants, also when aggression contents are anticipated, and a later attentional avoidance of aggression. The early depression-related bias in information processing may have maladaptive effects on the way depressed individuals perceive and function in social interaction and can, therefore, maintain depressed mood.
Ryan V. Raut; Abraham Z. Snyder; Anish Mitra; Dov Yellin; Naotaka Fujii; Rafael Malach; Marcus E. Raichle
In: Science Advances, vol. 7, no. 30, pp. eabf2709, 2021.
We propose and empirically support a parsimonious account of intrinsic, brain-wide spatiotemporal organization arising from traveling waves linked to arousal. We hypothesize that these waves are the predominant physiological process reflected in spontaneous functional magnetic resonance imaging (fMRI) signal fluctuations. The correlation structure ("functional connectivity") of these fluctuations recapitulates the large-scale functional organization of the brain. However, a unifying physiological account of this structure has so far been lacking. Here, using fMRI in humans, we show that ongoing arousal fluctuations are associated with global waves of activity that slowly propagate in parallel throughout the neocortex, thalamus, striatum, and cerebellum. We show that these waves can parsimoniously account for many features of spontaneous fMRI signal fluctuations, including topographically organized functional connectivity. Last, we demonstrate similar, cortex-wide propagation of neural activity measured with electrocorticography in macaques. These findings suggest that traveling waves spatiotemporally pattern brain-wide excitability in relation to arousal.
Gabrielle E. Reimann; Catherine Walsh; Kelsey D. Csumitta; Patrick McClure; Francisco Pereira; Alex Martin; Michal Ramot
In: Autism Research, vol. 14, no. 8, pp. 1670–1683, 2021.
Eye tracking provides insights into social processing deficits in autism spectrum disorder (ASD), especially in conjunction with dynamic, naturalistic free-viewing stimuli. However, the question remains whether gaze characteristics, such as preference for specific facial features, can be considered a stable individual trait, particularly in those with ASD. If so, how much data are needed for consistent estimations? To address these questions, we assessed the stability and robustness of gaze preference for facial features as incremental amounts of movie data were introduced for analysis. We trained an artificial neural network to create an object-based segmentation of naturalistic movie clips (14 s each, 7410 frames total). Thirty-three high-functioning individuals with ASD and 36 age- and IQ-equated typically developing individuals (age range: 12–30 years) viewed 22 Hollywood movie clips, each depicting a social interaction. As we evaluated combinations of one, three, five, eight, and 11 movie clips, gaze dwell times on core facial features became increasingly stable at within-subject, within-group, and between-group levels. Using a number of movie clips deemed sufficient by our analysis, we found that individuals with ASD displayed significantly less face-centered gaze (centralized on the nose; p < 0.001) but did not significantly differ from typically developing participants in eye or mouth looking times. Our findings validate gaze preference for specific facial features as a stable individual trait and highlight the possibility of misinterpretation with insufficient data. Additionally, we propose the use of a machine learning approach to stimuli segmentation to quickly and flexibly prepare dynamic stimuli for analysis. Lay Summary: Using a data-driven approach to segmenting movie stimuli, we examined varying amounts of data to assess the stability of social gaze in individuals with autism spectrum disorder (ASD). We found a reduction in social fixations in participants with ASD, driven by decreased attention to the center of the face. Our findings further support the validity of gaze preference for face features as a stable individual trait when sufficient data are used.
Miriam Rivero-Contreras; Paul E. Engelhardt; David Saldaña
In: Annals of Dyslexia, vol. 71, no. 1, pp. 170–187, 2021.
Easy-to-read guidelines recommend visual support and lexical simplification to facilitate text processing, but few empirical studies confirm a positive effect from these recommendations in individuals with dyslexia. This study examined the influence of the visual support and lexical simplification on sentence processing through eye movements at both the text- and word-level, and the differences between readers with and without dyslexia. Furthermore, we explored the influence of reading experience and vocabulary, as control variables. We tested 20 young adults with dyslexia and 20 chronological age-matched controls. Participants read 60 sentences in total. Half the sentences contained an image and the other half did not, and half contained a low-frequency word and half a high-frequency word. Results showed that visual support and lexical simplification facilitated sentence processing, potentially by jointly facilitating lexical semantic access. We also found that participants with lower print exposure and lower vocabulary benefited more from word-level lexical simplification. We conclude that both adaptations could benefit readers with low print exposure and smaller vocabularies, and therefore, to many dyslexic readers who show these characteristics.
Kathryn M. Rothenhoefer; Tao Hong; Aydin Alikaya; William R. Stauffer
Rare rewards amplify dopamine responses Journal Article
In: Nature Neuroscience, vol. 24, no. 4, pp. 465–469, 2021.
Dopamine prediction error responses are essential components of universal learning mechanisms. However, it is unknown whether individual dopamine neurons reflect the shape of reward distributions. Here, we used symmetrical distributions with differently weighted tails to investigate how the frequency of rewards and reward prediction errors influence dopamine signals. Rare rewards amplified dopamine responses, even when conventional prediction errors were identical, indicating a mechanism for learning the complexities of real-world incentives.
Yikang Zhu; Lihua Xu; Wenzheng Wang; Qian Guo; Shan Chen; Caidi Zhang; Tianhong Zhang; Xiaochen Hu; Paul Enck; Chunbo Li; Jianhua Sheng; Jijun Wang
In: Asian Journal of Psychiatry, vol. 66, pp. 1–6, 2021.
Interpersonal communication is a specific scenario in which patients with psychiatric symptoms may manifest different behavioral patterns due to psychopathology. This was a pilot study by eye-tracking technology to investigate attentive bias during social information processing in schizophrenia. We enrolled 39 patients with schizophrenia from Shanghai Mental Health Center and 42 age-, gender- and education-matched healthy controls. The experiment was a free-viewing task, in which pictures with three types of degree of interpersonal communication were shown. We used two measures: 1) initial fixation duration, 2) total gaze duration. The Positive and Negative Syndrome Scale (PANSS) was used to determine symptom severity. The ratio of first fixation duration for pictures of communicating vs. non-communicating persons was significantly lower in patients than in controls (Mann-Whitney U = 512
Jumpei Yamashita; Hiroki Terashima; Makoto Yoneya; Kazushi Maruya; Hidetaka Koya; Haruo Oishi; Hiroyuki Nakamura; Takatsune Kumada
In: PLoS ONE, vol. 16, no. 9, pp. 1–22, 2021.
Our daily activities require vigilance. Therefore, it is useful to externally monitor and predict our vigilance level using a straightforward method. It is known that the vigilance level is linked to pupillary fluctuations via Locus Coeruleus and Norepinephrine (LC-NE) system. However, previous methods of estimating long-term vigilance require monitoring pupillary fluctuations at rest over a long period. We developed a method of predicting the short-term vigilance level by monitoring pupillary fluctuation for a shorter period consisting of several seconds. The LC activity also fluctuates at a timescale of seconds. Therefore, we hypothesized that the short-term vigilance level could be estimated using pupillary fluctuations in a short period and quantified their amplitude as the Micro-Pupillary Unrest Index (M-PUI). We found an intra-individual trial-by-trial positive correlation between Reaction Time (RT) reflecting the short-term vigilance level and M-PUI in the period immediately before the target onset in a Psychomotor Vigilance Task (PVT). This relationship was most evident when the fluctuation was smoothed by a Hanning window of approximately 50 to 100 ms (including cases of down-sampled data at 100 and 50 Hz), and M-PUI was calculated in the period up to one or two seconds before the target onset. These results suggest that M-PUI can monitor and predict fluctuating levels of vigilance. M-PUI is also useful for examining pupillary fluctuations in a short period for elucidating the psychophysiological mechanisms of short-term vigilance.
Guoli Yan; Zebo Lan; Zhu Meng; Yingchao Wang; Valerie Benson
In: Scientific Studies of Reading, vol. 25, no. 4, pp. 287–303, 2021.
Phonological coding plays an important role in reading for hearing students. Experimental findings regarding phonological coding in deaf readers are controversial, and whether deaf readers are able to use phonological coding remains unclear. In the current study we examined whether Chinese deaf students could use phonological coding during sentence reading. Deaf middle school students, chronological age-matched hearing students, and reading ability-matched hearing students had their eye movements recorded as they read sentences containing correctly spelled characters, homophones, or unrelated characters. Both hearing groups had shorter total reading times on homophones than they did on unrelated characters. In contrast, no significant difference was found between homophones and unrelated characters for the deaf students. However, when the deaf group was divided into more-skilled and less-skilled readers according to their scores on reading fluency, the homophone advantage noted for the hearing controls was also observed for the more-skilled deaf students.
Haiyan Zheng; Xiaoxiao Ying; Xianghang He; Jia Qu; Fang Hou
In: Investigative Ophthalmology & Visual Science, vol. 62, no. 9, pp. 1–11, 2021.
PURPOSE. To investigate the temporal characteristics of visual processing at the fovea and the periphery in high myopia. METHODS. Eighteen low (LM, ≤ −0.50 and > −6.00 D) and 18 high myopic (HM, ≤ −6.00 D) participants took part in this study. The contrast thresholds in an orientation discrimination task under various stimulus onset asynchrony (SOA) masking conditions were measured at the fovea and a more peripheral area (7°) for the two groups. An elaborated perceptual template model (ePTM) was fit to the behavioral data for each participant. RESULTS. An analysis of variance with three factors (SOA, degree of myopia and eccentricity) was performed on the threshold data. The interaction between SOA and degree of myopia in the fovea was significant (F (4, 128) = 2.66
Beier Yao; Martin Rolfs; Christopher McLaughlin; Emily L. Isenstein; Sylvia B. Guillory; Hannah Grosman; Deborah A. Kashy; Jennifer H. Foss-Feig; Katharine N. Thakkar
In: Journal of Vision, vol. 21, no. 8, pp. 1–20, 2021.
Corollary discharge (CD) signals are “copies” of motor signals sent to sensory regions that allow animals to adjust sensory consequences of self-generated actions. Autism spectrum disorder (ASD) is characterized by sensory and motor deficits, which may be underpinned by altered CD signaling. We evaluated oculomotor CD using the blanking task, which measures the influence of saccades on visual perception, in 30 children with ASD and 35 typically developing (TD) children. Participants were instructed to make a saccade to a visual target. Upon saccade initiation, the presaccadic target disappeared and reappeared to the left or right of the original position. Participants indicated the direction of
Yan-Bo Zhang; Peng-Chong Wang; Yun Ma; Xiang-Yun Yang; Fan-Qiang Meng; Simon A Broadley; Jing Sun; Zhan-Jiang Li
In: World Journal of Psychiatry, vol. 11, no. 3, pp. 73–86, 2021.
BACKGROUND: Illness anxiety disorder (IAD) is a common, distressing, and debilitating condition with the key feature being a persistent conviction of the possibility of having one or more serious or progressive physical disorders. Because eye movements are guided by visual-spatial attention, eye-tracking technology is a comparatively direct, continuous measure of attention direction and speed when stimuli are oriented. Researchers have tried to identify selective visual attention biases by tracking eye movements within dot-probe paradigms because dot-probe paradigm can distinguish these attentional biases more clearly. AIM: To examine the association between IAD and biased processing of illness-related information. METHODS: A case-control study design was used to record eye movements of individuals with IAD and healthy controls while participants viewed a set of pictures from four categories (illness-related, socially threatening, positive, and neutral images). Biases in initial orienting were assessed from the location of the initial shift in gaze, and biases in the maintenance of attention were assessed from the duration of gaze that was initially fixated on the picture per image category. RESULTS: The eye movement of the participants in the IAD group was characterized by an avoidance bias in initial orienting to illness-related pictures. There was no evidence of individuals with IAD spending significantly more time viewing illness-related images compared with other images. Patients with IAD had an attention bias at the early stage and overall attentional avoidance. In addition, this study found that patients with significant anxiety symptoms showed attention bias in the late stages of attention processing. CONCLUSION: Illness-related information processing biases appear to be a robust feature of IAD and may have an important role in explaining the etiology and maintenance of the disorder.
TianHong Zhang; YingYu Yang; LiHua Xu; XiaoChen Tang; YeGang Hu; Xin Xiong; YanYan Wei; HuiRu Cui; YingYing Tang; HaiChun Liu; Tao Chen; Zhi Liu; Li Hui; ChunBo Li; XiaoLi Guo; JiJun Wang
In: The World Journal of Biological Psychiatry, pp. 1–13, 2021.
Objectives: We used eye-tracking to evaluate multiple facial context processing and event-related potential (ERP) to evaluate multiple facial recognition in individuals at clinical high risk (CHR) for psychosis. Methods: In total, 173 subjects (83 CHRs and 90 healthy controls [HCs]) were included and their emotion perception performances were accessed. A total of 40 CHRs and 40 well-matched HCs completed an eye-tracking task where they viewed pictures depicting a person in the foreground, presented as context-free, context-compatible, and context-incompatible. During the two-year follow-up, 26 CHRs developed psychosis, including 17 individuals who developed first-episode schizophrenia (FES). Eighteen well-matched HCs were made to complete the face number detection ERP task with image stimuli of one, two, or three faces. Results: Compared to the HC group, the CHR group showed reduced visual attention to contextual processing when viewing multiple faces. With the increasing complexity of contextual faces, the differences in eye-tracking characteristics also increased. In the ERP task, the N170 amplitude decreased with a higher face number in FES patients, while it increased with a higher face number in HCs. Conclusions: Individuals in the very early phase of psychosis showed facial processing deficits with supporting evidence of different scan paths during context processing and disruption of N170 during multiple facial recognition.
Li Zhang; Guoli Yan; Valerie Benson
In: PLoS ONE, vol. 16, no. 5, pp. 1–14, 2021.
The current study examined how emotional faces impact on attentional control at both involuntary and voluntary levels in children with and without autism spectrum disorder (ASD). A non-face single target was either presented in isolation or synchronously with emotional face distractors namely angry, happy and neutral faces. ASD and typically developing children made more erroneous saccades towards emotional distractors relative to neutral distractors in parafoveal and peripheral conditions. Remote distractor effects were observed on saccade latency in both groups regardless of distractor type, whereby time taken to initiate an eye movement to the target was longest in central distractor conditions, followed by parafoveal and peripheral distractor conditions. The remote distractor effect was greater for angry faces compared to happy faces in the ASD group. Proportions of failed disengagement trials from central distractors, for the first saccade, were higher in the angry distractor condition compared with the other two distractor conditions in ASD, and this effect was absent for the typical group. Eye movement results suggest difficulties in disengaging from fixated angry faces in ASD. Atypical disengagement from angry faces at the voluntary level could have consequences for the development of higher-level socio-communicative skills in ASD.
Elizabeth H. X. Thomas; Maria Steffens; Christopher Harms; Susan L. Rossell; Caroline Gurvich; Ulrich Ettinger
In: Psychophysiology, vol. 58, no. 1, pp. e13706, 2021.
Deficits on saccade tasks, particularly antisaccade performance, have been reliably reported in schizophrenia. However, less evidence is available on saccade performance in relation to schizotypy, a personality constellation harboring risk for schizophrenia. Here, we report a large empirical study of the associations of schizotypy and neuroticism with antisaccade and prosaccade performance (Study I). Additionally, we carried out meta-analyses of the association between schizotypy and antisaccade error rate (Study II). In Study I
Greta Krasimirova Todorova; Frank Earl Pollick; Lars Muckli
In: Neuropsychologia, vol. 163, pp. 108070, 2021.
For autistic individuals, sensory stimulation can be experienced as overwhelming. Models of predictive coding postulate that cortical mechanisms disamplify predictable information and amplify prediction errors that surpass a defined precision level. In autism, the neuronal processing is putting an inflexibly high precision on prediction errors according to the HIPPEA theory (High, Inflexible Precision of Prediction Errors in Autism). We used an apparent motion paradigm to test this prediction. In apparent motion paradigms, the illusory motion of an object creates a prediction about where and when an internally generated token would be moving along the apparent motion trace. This illusion facilitates the perception of a flashing stimulus (target) appearing in-time with the apparent motion token and is perceived as a predictable event (predictable target). In contrast, a flashing stimulus appearing out-of-time with the apparent motion illusion is an unpredictable target that is less often detected even though it produces a prediction error signal. If a prediction error does not surpass a given precision threshold the stimulation event is discounted and therefore less often detected than predictable tokens. In autism, the precision threshold is lower and the same prediction errors (unpredictable target) triggers a detection similar to that of a predictable flash stimulus. To test this hypothesis, we recruited 11 autistic males and 9 neurotypical matched controls. The participants were tasked to detect flashing stimuli placed on an apparent motion trace either in-time or out-of-time with the apparent motion illusion. Descriptively, 66% (6/9) of neurotypical and 64% (7/11) of autistic participants were better at detecting predictable targets. The prediction established by illusory motion appears to assist autistic and neurotypical individuals equally in the detection of predictable over unpredictable targets. Importantly, 55% (6/11) of autistic participants had faster responses for unpredictable targets, whereas only 22% (2/9) of neurotypicals had faster responses to unpredictable compared to predictable targets. Hence, these tentative results suggest that for autistic participants, unpredictable targets produce an above threshold prediction error, which leads to faster response. This difference in unpredictable target detection can be encapsulated under the HIPPEA theory, suggesting that precision setting could be aberrant in autistic individuals with respect to prediction errors. These tentative results should be considered in light of the small sample. For this reason, we provide the full set of materials necessary to replicate and extend the results.
Chiara Tortelli; Marco Turi; David C. Burr; Paola Binda
In: Journal of Autism and Developmental Disorders, vol. 51, no. 8, pp. 2908–2919, 2021.
We measured the pupil response to a light stimulus subject to a size illusion and found that stimuli perceived as larger evoke a stronger pupillary response. The size illusion depends on combining retinal signals with contextual 3D information; contextual processing is thought to vary across individuals, being weaker in individuals with stronger autistic traits. Consistent with this theory, autistic traits correlated negatively with the magnitude of pupil modulations in our sample of neurotypical adults; however, psychophysical measurements of the illusion did not correlate with autistic traits, or with the pupil modulations. This shows that pupillometry provides an accurate objective index of complex perceptual processes, particularly useful for quantifying interindividual differences, and potentially more informative than standard psychophysical measures.
Chiara Tortelli; Marco Turi; David C. Burr; Paola Binda
In: eLife, vol. 10, pp. 1–13, 2021.
We measured the modulation of pupil-size (in constant lighting) elicited by observing transparent surfaces of black and white moving dots, perceived as a cylinder rotating about its vertical axis. The direction of rotation was swapped periodically by flipping stereo-depth of the two surfaces. Pupil size modulated in synchrony with the changes in front-surface color (dilating when black). The magnitude of pupillary modulation was larger for human participants with higher Autism-Spectrum Quotient (AQ), consistent with a local perceptual style, with attention focused on the front surface. The modulation with surface color, and its correlation with AQ, was equally strong when participants passively viewed the stimulus. No other indicator, including involuntary pursuit eye-movements, covaried with AQ. These results reinforce our previous report with a similar bistable stimulus (Turi, Burr, & Binda, 2018), and go on to show that bistable illusory motion is not necessary for the effect, or its dependence on AQ.
Matthew J. Traxler; Timothy Banh; Madeline M. Craft; Kurt Winsler; Trevor A. Brothers; Liv J. Hoversten; Pilar Piñar; David P. Corina
In: Applied Psycholinguistics, vol. 42, no. 3, pp. 601–630, 2021.
Deaf readers may have larger perceptual spans than ability-matched hearing native English readers, allowing them to read more efficiently (Belanger & Rayner, 2015). To further test the hypothesis that deaf and hearing readers have different perceptual spans, the current study uses eye-movement data from two experiments in which deaf American Sign Language-English bilinguals, hearing native English speakers, and hearing Chinese-English bilinguals read semantically unrelated sentences and answered comprehension questions after a proportion of them. We analyzed skip rates, fixation times, and accuracy on comprehension questions. In addition, we analyzed how lexical properties of words affected skipping behavior and fixation durations. Deaf readers skipped words more often than native English speakers, who skipped words more often than Chinese-English bilinguals. Deaf readers had shorter first-pass fixation times than the other two groups. All groups' skipping behaviors were affected by lexical frequency. Deaf readers' comprehension did not differ from hearing Chinese-English bilinguals, despite greater skipping and shorter fixation times. Overall, the eye-tracking findings align with Belanger's word processing efficiency hypothesis. Effects of lexical frequency on skipping behavior indicated further that eye movements during reading remain under cognitive control in deaf readers.
Hamid B. Turker; Elizabeth Riley; Wen Ming Luh; Stan J. Colcombe; Khena M. Swallow
In: NeuroImage, vol. 236, pp. 118047, 2021.
The locus coeruleus (LC) plays a central role in regulating human cognition, arousal, and autonomic states. Efforts to characterize the LC's function in humans using functional magnetic resonance imaging have been hampered by its small size and location near a large source of noise, the fourth ventricle. We tested whether the ability to characterize LC function is improved by employing neuromelanin-T1 weighted images (nmT1) for LC localization and multi-echo functional magnetic resonance imaging (ME-fMRI) for estimating intrinsic functional connectivity (iFC). Analyses indicated that, relative to a probabilistic atlas, utilizing nmT1 images to individually localize the LC increases the specificity of seed time series and clusters in the iFC maps. When combined with independent components analysis (ME-ICA), ME-fMRI data provided significant improvements in the temporal signal to noise ratio and DVARS relative to denoised single echo data (1E-fMRI). The effects of acquiring nmT1 images and ME-fMRI data did not appear to only reflect increases in power: iFC maps for each approach overlapped only moderately. This is consistent with findings that ME-fMRI offers substantial advantages over 1E-fMRI acquisition and denoising. It also suggests that individually identifying LC with nmT1 scans is likely to reduce the influence of other nearby brainstem regions on estimates of LC function.
Kathryn E. Unruh; Walker S. McKinney; Erin K. Bojanek; Kandace K. Fleming; John A. Sweeney; Matthew W. Mosconi
In: Molecular Autism, vol. 12, no. 1, pp. 1–25, 2021.
Background: Sensorimotor issues are common in autism spectrum disorder (ASD), related to core symptoms, and predictive of worse functional outcomes. Deficits in rapid behaviors supported primarily by feedforward mechanisms, and continuous, feedback-guided motor behaviors each have been reported, but the degrees to which they are distinct or co-segregate within individuals and across development are not well understood. Methods: We characterized behaviors that varied in their involvement of feedforward control relative to feedback control across skeletomotor (precision grip force) and oculomotor (saccades) control systems in 109 individuals with ASD and 101 age-matched typically developing controls (range: 5–29 years) including 58 individuals with ASD and 57 controls who completed both grip and saccade tests. Grip force was examined across multiple force (15, 45, and 85% MVC) and visual gain levels (low, medium, high). Maximum grip force also was examined. During grip force tests, reaction time, initial force output accuracy, variability, and entropy were examined. For the saccade test, latency, accuracy, and trial-wise variability of latency and accuracy were examined. Results: Relative to controls, individuals with ASD showed similar accuracy of initial grip force but reduced accuracy of saccadic eye movements specific to older ages of our sample. Force variability was greater in ASD relative to controls, but saccade gain variability (across trials) was not different between groups. Force entropy was reduced in ASD, especially at older ages. We also find reduced grip strength in ASD that was more severe in dominant compared to non-dominant hands. Limitations: Our age-related findings rely on cross-sectional data. Longitudinal studies of sensorimotor behaviors and their associations with ASD symptoms are needed. Conclusions: We identify reduced accuracy of initial motor output in ASD that was specific to the oculomotor system implicating deficient feedforward control that may be mitigated during slower occurring behaviors executed in the periphery. Individuals with ASD showed increased continuous force variability but similar levels of trial-to-trial saccade accuracy variability suggesting that feedback-guided refinement of motor commands is deficient specifically when adjustments occur rapidly during continuous behavior. We also document reduced lateralization of grip strength in ASD implicating atypical hemispheric specialization.
Michael A. Urbin; Charles W. Lafe; Tyler W. Simpson; George F. Wittenberg; Bharath Chandrasekaran; Douglas J. Weber
In: Brain Stimulation, vol. 14, no. 4, pp. 990–1001, 2021.
Background: Transcutaneous stimulation of the external ear is thought to recruit afferents of the auricular vagus nerve, providing a means to activate noradrenergic pathways in the central nervous system. Findings from human studies examining the effects of auricular stimulation on noradrenergic biomarkers have been mixed, possibly relating to the limited and variable parameter space explored to date. Objective: We tested the extent to which brief pulse trains applied to locations of auricular innervation (canal and concha) elicit acute pupillary responses (PRs) compared to a sham location (lobe). Pulse amplitude and frequency were varied systematically to examine effects on PR features. Methods: Participants (n = 19) underwent testing in three separate experiments, each with stimulation applied to a different external ear location. Perceptual threshold (PT) was measured at the beginning of each experiment. Pulse trains (∼600 ms) consisting of different amplitude (0.0xPT, 0.8xPT, 1.0xPT, 1.5xPT, 2.0xPT) and frequency (25 Hz, 300 Hz) combinations were administered during eye tracking procedures. Results: Stimulation to all locations elicited PRs which began approximately halfway through the pulse train and peaked shortly after the final pulse (≤1 s). PR size and incidence increased with pulse amplitude and tended to be greatest with canal stimulation. Higher pulse frequency shortened the latency of PR onset and peak dilation. Changes in pupil diameter elicited by pulse trains were weakly associated with baseline pupil diameter. Conclusion: (s): Auricular stimulation elicits acute PRs, providing a basis to synchronize neuromodulator release with task-related neural spiking which preclinical studies show is a critical determinant of therapeutic effects. Further work is needed to dissociate contributions from vagal and non-vagal afferents mediating activation of the biomarker.
Nathan Van der Stoep; M. J. Van der Smagt; C. Notaro; Z. Spock; M. Naber
In: Scientific Reports, vol. 11, pp. 707, 2021.
Pupillometry has received increased interest for its usefulness in measuring various sensory processes as an alternative to behavioural assessments. This is also apparent for multisensory investigations. Studies of the multisensory pupil response, however, have produced conflicting results. Some studies observed super-additive multisensory pupil responses, indicative of multisensory integration (MSI). Others observed additive multisensory pupil responses even though reaction time (RT) measures were indicative of MSI. Therefore, in the present study, we investigated the nature of the multisensory pupil response by combining methodological approaches of previous studies while using supra-threshold stimuli only. In two experiments we presented auditory and visual stimuli to observers that evoked a(n) (onset) response (be it constriction or dilation) in a simple detection task and a change detection task. In both experiments, the RT data indicated MSI as shown by race model inequality violation. Still, the multisensory pupil response in both experiments could best be explained by linear summation of the unisensory pupil responses. We conclude that the multisensory pupil response for supra-threshold stimuli is additive in nature and cannot be used as a measure of MSI, as only a departure from additivity can unequivocally demonstrate an interaction between the senses.
Chiara Visentin; Chiara Valzolgher; Matteo Pellegatti; Paola Potente; Francesco Pavani; Nicola Prodi
In: International Journal of Audiology, pp. 1–13, 2021.
Objective: The aim of this study was to assess to what extent simultaneousl-obtained measures of listening effort (task-evoked pupil dilation, verbal response time [RT], and self-rating) could be sensitive to auditory and cognitive manipulations in a speech perception task. The study also aimed to explore the possible relationship between RT and pupil dilation. Design: A within-group design was adopted. All participants were administered the Matrix Sentence Test in 12 conditions (signal-to-noise ratios [SNR] of −3, −6, −9 dB; attentional resources focussed vs divided; spatial priors present vs absent). Study sample: Twenty-four normal-hearing adults, 20–41 years old (M = 23.5), were recruited in the study. Results: A significant effect of the SNR was found for all measures. However, pupil dilation discriminated only partially between the SNRs. Neither of the cognitive manipulations were effective in modulating the measures. No relationship emerged between pupil dilation, RT and self-ratings. Conclusions: RT, pupil dilation, and self-ratings can be obtained simultaneously when administering speech perception tasks, even though some limitations remain related to the absence of a retention period after the listening phase. The sensitivity of the three measures to changes in the auditory environment differs. RTs and self-ratings proved most sensitive to changes in SNR.
Renée M. Visser; Joe Bathelt; H. Steven Scholte; Merel Kindt
In: Journal of Neuroscience, vol. 41, no. 50, pp. 10278–10292, 2021.
Most of our knowledge about human emotional memory comes from animal research. Based on this work, the amygdala is often labelled the brain's "fear center", but it is unclear to what degree neural circuitries underlying fear and extinction learning are conserved across species. Neuroimaging studies in humans yield conflicting findings, with many studies failing to show amygdala activation in response to learned threat. Such null-findings are often treated as resulting from MRI-specific problems related to measuring deep brain structures. Here we test this assumption in a mega-analysis of three studies on fear acquisition (n=98; 68 female) and extinction learning (n=79; 53 female). The conditioning procedure involved presentation of two pictures of faces and two pictures of houses: one of each pair was followed by an electric shock (CS+), the other one was never followed by a shock (CS-), and participants were instructed to learn these contingencies. Results revealed widespread responses to the CS+ compared to CS- in the fear network, including anterior insula, midcingulate cortex, thalamus and bed nucleus of the stria terminalis, but not the amygdala, which actually responded stronger to the CS-. Results were independent of spatial smoothing, and individual differences in trait anxiety and conditioned pupil responses. In contrast, robust amygdala activation distinguished faces from houses, refuting the idea that poor signal could account for the absence of effects. Moving forward, we suggest that apart from imaging larger samples at higher resolution, alternative statistical approaches may be employed to identify cross-species similarities in fear and extinction learning.
Christoph J Völter; Ludwig Huber; Christoph J Völter
In: Biology Letters, vol. 17, pp. 1–5, 2021.
Contact causality is one of the fundamental principles allowing us to make sense of our physical environment. From an early age, humans perceive spatio-temporally contiguous launching events as causal. Surprisingly little is known about causal perception in non-human animals, particularly outside the primate order. Violation-of-expectation paradigms in combination with eye-tracking and pupillometry have been used to study physical expectations in human infants. In the current study, we establish this approach for dogs (Canis familiaris). We presented dogs with realistic three-dimensional animations of launching events with contact (regular launching event) or without contact between the involved objects. In both conditions, the objects moved with the same timing and kinematic properties. The dogs tracked the object movements closely throughout the study but their pupils were larger in the no-contact condition and they looked longer at the object initiating the launch after the no-contact event compared to the contact event. We conclude that dogs have implicit expectations about contact causality.
Cécile Vullings; Preeti Verghese
Mapping the binocular scotoma in macular degeneration Journal Article
In: Journal of Vision, vol. 21, no. 3, pp. 1–12, 2021.
When the scotoma is binocular in macular degeneration (MD), it often obscures objects of interest, causing individuals to miss information. To map the binocular scotoma as precisely as current methods that map the monocular scotoma, we propose an iterative eye-tracker method. Study participants included nine individuals with MD and four age-matched controls. We measured the extent of the monocular scotomata using a scanning laser ophthalmoscope/optical coherence tomography (SLO/OCT). Then, we precisely mapped monocular and binocular scotomata with an eye tracker, while fixation was monitored. Participants responded whenever they detected briefly flashed dots, which were first presented on a coarse grid, and then at manually selected points to refine the shape and edges of the scotoma. Monocular scotomata measured in the SLO and eye tracker are highly similar, validating the eye-tracking method for scotoma mapping. Moreover, all participants used clustered fixation loci corresponding to their dominant preferred fixation locus. Critically, for individuals with binocular scotomata, the binocular map from the eye tracker was consistent with the overlap of the monocular scotoma profiles from the SLO. Thus, eye-tracker-based perimetry offers a reliable and sensitive tool for measuring both monocular and binocular scotomata, unlike the SLO/OCT that is limited to monocular viewing.
Josefine Waldthaler; Lena Stock; Charlotte Krüger-Zechlin; Lars Timmermann
In: Neuropsychologia, vol. 163, pp. 108082, 2021.
The antisaccade task is an established eye-tracking paradigm to explore response inhibition. While many studies showed that antisaccade performance is impaired in Parkinson's disease (PD), the effect of dopaminergic medication is still an area of debate. According to the dopamine overdose hypothesis, intrinsic basal dopamine levels in ventral parts of the striatum determine whether levodopa intake has beneficial or detrimental effects on dopamine-dependent cognitive tasks. The objective of this study was therefore to explore the effect of several disease-related factors on changes in antisaccade performance after levodopa intake in PD. Thirty-five individuals with PD (and 30 healthy controls) performed antisaccades in OFF and ON medication state. Multiple linear regressions were calculated to predict the change in antisaccade latency, directive errors and express saccade rate based on age at PD onset, disease duration, levodopa-equivalent daily dose, motor symptom severity and executive functions. Levodopa intake did not alter antisaccade performance on a group level. However, the effect of levodopa was differentially modulated by age at PD onset and motor symptom severity. Earlier disease onset and milder motor symptoms in OFF medication state were associated with reduced response inhibition capacity after levodopa intake measured as increased express saccade and error rates. Our results indicate that levodopa may have opposing effects on oculomotor response inhibition dependent on the age at PD onset and motor disease severity. Assuming less dopaminergic loss in ventral parts of the striatum in early compared to late onset PD, these findings support the dopamine overdose hypothesis.
Wendy Wang; Meaghan Clough; Owen White; Neil Shuey; Anneke Van Der Walt; Joanne Fielding
In: Frontiers in Neurology, vol. 12, pp. 772513, 2021.
Objective: To determine whether cognitive impairments in patients with Idiopathic Intracranial Hypertension (IIH) are correlated with changes in visual processing, weight, waist circumference, mood or headache, and whether they change over time. Methods: Twenty-two newly diagnosed IIH patients participated, with a subset assessed longitudinally at 3 and 6 months. Both conventional and novel ocular motor tests of cognition were included: Symbol Digit Modalities Test (SDMT), Stroop Colour and Word Test (SCWT), Digit Span, California Verbal Learning Test (CVLT), prosaccade (PS) task, antisaccade (AS) task, interleaved antisaccade-prosaccade (AS-PS) task. Patients also completed headache, mood, and visual functioning questionnaires. Results: IIH patients performed more poorly than controls on the SDMT (p< 0.001), SCWT (p = 0.021), Digit Span test (p< 0.001) and CVLT (p = 0.004) at baseline, and generated a higher proportion of AS errors in both the AS (p< 0.001) and AS-PS tasks (p = 0.007). Further, IIH patients exhibited prolonged latencies on the cognitively complex AS-PS task (p = 0.034). While weight, waist circumference, headache and mood did not predict performance on any experimental measure, increased retinal nerve fibre layer (RNFL) was associated with AS error rate on both the block [F(3, 19)=3.22
Thomas D. W. Wilcockson; Emmanuel M. Pothos; Ashley M. Osborne; Trevor J. Crawford
In: Addictive Behaviors, vol. 118, pp. 1–7, 2021.
Introduction: Substance use causes attentional biases for substance-related stimuli. Both bottom-up (preferential processing) and top-down (inhibitory control) processes are involved in attentional biases. We explored these aspects of attentional bias by using dependent and non-dependent cigarette smokers in order to see whether these two groups would differ in terms of general inhibitory control, bottom-up attentional bias, and top-down attentional biases. This enables us to see whether consumption behaviour would affect these cognitive responses to smoking-related stimuli. Methods: Smokers were categorised as either dependent (N = 26) or non-dependent (N = 34) smokers. A further group of non-smokers (N = 32) were recruited to act as controls. Participants then completed a behavioural inhibition task with general stimuli, a smoking-related eye tracking version of the dot-probe task, and an eye-tracking inhibition task with smoking-related stimuli. Results: Results indicated that dependent smokers had decreased inhibition and increased attentional bias for smoking-related stimuli (and not control stimuli). By contrast, a decreased inhibition for smoking-related stimuli (in comparison to control stimuli) was not observed for non-dependent smokers. Conclusions: Preferential processing of substance-related stimuli may indicate usage of a substance, whereas poor inhibitory control for substance-related stimuli may only emerge if dependence develops. The results suggest that how people engage with substance abuse is important for top-down attentional biases.
Lauren H. Williams; Ann J. Carrigan; Megan Mills; William F. Auffermann; Anina N. Rich; Trafton Drew
In: Journal of Medical Imaging, vol. 8, no. 04, pp. 1–24, 2021.
Purpose: Experienced radiologists have enhanced global processing ability relative to novices, allowing experts to rapidly detect medical abnormalities without performing an exhaustive search. However, evidence for global processing models is primarily limited to two-dimensional image interpretation, and it is unclear whether these findings generalize to volumetric images, which are widely used in clinical practice. We examined whether radiologists searching volumetric images use methods consistent with global processing models of expertise. In addition, we investigated whether search strategy (scanning/drilling) differs with experience level.
Approach: Fifty radiologists with a wide range of experience evaluated chest computed-tomography scans for lung nodules while their eye movements and scrolling behaviors were tracked. Multiple linear regressions were used to determine: (1) how search behaviors differed with years of experience and the number of chest CTs evaluated per week and (2) which search behaviors predicted better performance.
Results: Contrary to global processing models based on 2D images, experience was unrelated to measures of global processing (saccadic amplitude, coverage, time to first fixation, search time, and depth passes) in this task. Drilling behavior was associated with better accuracy than scanning behavior when controlling for observer experience. Greater image coverage was a strong predictor of task accuracy.
Conclusions: Global processing ability may play a relatively small role in volumetric image interpretation, where global scene statistics are not available to radiologists in a single glance. Rather, in volumetric images, it may be more important to engage in search strategies that support a more thorough search of the image.
Lena Wimmer; Gregory Currie; Stacie Friend; Heather Jane Ferguson
In: Imagination, Cognition and Personality, vol. 41, no. 1, pp. 54–86, 2021.
Two pre-registered studies investigated associations of lifetime exposure to fiction, applying a battery of self-report, explicit and implicit indicators. Study 1 ( N = 150 university students) tested the relationships between exposure to fiction and social and moral cognitive abilities in a lab setting, using a correlational design. Results failed to reveal evidence for enhanced social or moral cognition with increasing lifetime exposure to narrative fiction. Study 2 followed a cross-sectional design and compared 50–80 year-old fiction experts ( N = 66), non-fiction experts ( N = 53), and infrequent readers ( N = 77) regarding social cognition, general knowledge, imaginability, and creativity in an online setting. Fiction experts outperformed the remaining groups regarding creativity, but not regarding social cognition or imaginability. In addition, both fiction and non-fiction experts demonstrated higher general knowledge than infrequent readers. Taken together, the present results do not support theories postulating benefits of narrative fiction for social cognition, but suggest that reading fiction may be associated with a specific gain in creativity, and that print (fiction or non-fiction) exposure has a general enhancement effect on world knowledge.
Matthew B. Winn; Katherine H. Teece
In: Ear and Hearing, vol. 42, no. 3, pp. 584–595, 2021.
OBJECTIVES: Slowed speaking rate was examined for its effects on speech intelligibility, its interaction with the benefit of contextual cues, and the impact of these factors on listening effort in adults with cochlear implants. DESIGN: Participants (n = 21 cochlear implant users) heard high- and low-context sentences that were played at the original speaking rate, as well as a slowed (1.4× duration) speaking rate, using uniform pitch-synchronous time warping. In addition to intelligibility measures, changes in pupil dilation were measured as a time-varying index of processing load or listening effort. Slope of pupil size recovery to baseline after the sentence was used as an index of resolution of perceptual ambiguity. RESULTS: Speech intelligibility was better for high-context compared to low-context sentences and slightly better for slower compared to original-rate speech. Speech rate did not affect magnitude and latency of peak pupil dilation relative to sentence offset. However, baseline pupil size recovered more substantially for slower-rate sentences, suggesting easier processing in the moment after the sentence was over. The effect of slowing speech rate was comparable to changing a sentence from low context to high context. The effect of context on pupil dilation was not observed until after the sentence was over, and one of two analyses suggested that context had greater beneficial effects on listening effort when the speaking rate was slower. These patterns maintained even at perfect sentence intelligibility, suggesting that correct speech repetition does not guarantee efficient or effortless processing. With slower speaking rates, there was less variability in pupil dilation slopes following the sentence, implying mitigation of some of the difficulties shown by individual listeners who would otherwise demonstrate prolonged effort after a sentence is heard. CONCLUSIONS: Slowed speaking rate provides release from listening effort when hearing an utterance, particularly relieving effort that would have lingered after a sentence is over. Context arguably provides even more release from listening effort when speaking rate is slower. The pattern of prolonged pupil dilation for faster speech is consistent with increased need to mentally correct errors, although that exact interpretation cannot be verified with intelligibility data alone or with pupil data alone. A pattern of needing to dwell on a sentence to disambiguate misperceptions likely contributes to difficulty in running conversation where there are few opportunities to pause and resolve recently heard utterances.
Léa Entzmann; Nathalie Guyader; Louise Kauffmann; Juliette Lenouvel; Clémence Charles; Carole Peyrin; Roman Vuillaume; Martial Mermillod
In: Cognitive Science, vol. 45, no. 10, pp. e13042, 2021.
Previous studies have shown that the human visual system can detect a face and elicit a saccadic eye movement toward it very efficiently compared to other categories of visual stimuli. In the first experiment, we tested the influence of facial expressions on fast face detection using a saccadic choice task. Face-vehicle pairs were simultaneously presented and participants were asked to saccade toward the target (the face or the vehicle). We observed that saccades toward faces were initiated faster, and more often in the correct direction, than saccades toward vehicles, regardless of the facial expressions (happy, fearful, or neutral). We also observed that saccade endpoints on face images were lower when the face was happy and higher when it was neutral. In the second experiment, we explicitly tested the detection of facial expressions. We used a saccadic choice task with emotional-neutral pairs of faces and participants were asked to saccade toward the emotional (happy or fearful) or the neutral face. Participants were faster when they were asked to saccade toward the emotional face. They also made fewer errors, especially when the emotional face was happy. Using computational modeling, we showed that this happy face advantage can, at least partly, be explained by perceptual factors. Also, saccade endpoints were lower when the target was happy than when it was fearful. Overall, we suggest that there is no automatic prioritization of emotional faces, at least for saccades with short latencies, but that salient local face features can automatically attract attention.
Peter Essig; Yannick Sauer; Siegfried Wahl
In: Translational Vision Science and Technology, vol. 10, no. 12, pp. 12, 2021.
Purpose: The aim of the current study was to develop and validate an automated contrast sensitivity (CS) test using a live-detection of optokinetic nystagmus (OKN) and an adaptive psychometric procedure. In addition, the study sought to replicate the known effect of defocus on CS for the OKN-based measurements in emmetropic partic-ipants. Methods: Fifteen participants viewed a horizontally moving grating while their eyes were tracked with an infra-red (IR) eye-tracker. To simulate the clinical conditions of the CS measurements, the participants were stimulated monocularly as the left eye was occluded by an IR filter. The horizontal eye position was continuously analyzed for OKN responses, and the stimulus contrast was changed by an adaptive psychometric method depending on the outcome. Furthermore, the newly proposed OKN live-detection was verified against an offline analysis and an expert-observer judgement. The OKN-based CS was measured for six spatial frequencies at normal vision and three levels of defocus using spherical convex lenses. Results: The newly proposed OKN live-detection method showed a sufficient detection performance for implementation of adaptive procedures, and the detection rate is similar or better compared to offline detection methods. Spatial frequency and defocus had a significant effect on the OKN-based CS (P < 0.0001 for both). Conclusions: The current study presents a novel method to measure motion CS in an automated way, combining the real-time detection of OKN and an adaptive psychometric procedure. Furthermore, the known effect of defocus on CS was successfully repli-cated with the newly developed tool. Translational Relevance: OKN-based CS is a novel approach to assess spatial vision, which is sensitive to subtle effects of defocus, allowing use with nonverbal patients and infants. Furthermore, the newly developed tool may improve the performance of such measurements.
Barbara Feulner; Danilo Postin; Caspar M. Schwiedrzik; Arezoo Pooresmaeili
In: eNeuro, vol. 8, no. 5, pp. 1–17, 2021.
Humans can use their previous experience in form of statistical priors to improve decisions. It is, however, unclear how such priors are learned and represented. Importantly, it has remained elusive whether prior learning is independent of the sensorimotor system involved in the learning process or not, as both modality-specific and modality-general learning have been reported in the past. Here, we used a saccadic eye movement task to probe the learning and representation of a spatial prior across a few trials. In this task, learning occurs in an unsupervised manner and through encountering trial-by-trial visual hints drawn from a distribution centered on the target location. Using a model-comparison approach, we found that participants' prior knowledge is largely represented in the form of their previous motor actions, with minimal influence from the previously seen visual hints. By using two different motor contexts for response (looking either at the estimated target lo-cation, or exactly opposite to it), we could further compare whether prior experience obtained in one motor context can be transferred to the other. Although learning curves were highly similar, and participants seemed to use the same strategy for both response types, they could not fully transfer their knowledge between con-texts, as performance and confidence ratings dropped after a switch of the required response. Together, our results suggest that humans preferably use the internal representations of their previous motor actions, rather than past incoming sensory information, to form statistical sensorimotor priors on the timescale of a few trials.
Jolande Fooken; Pooja Patel; Christina B. Jones; Martin J. McKeown; Miriam Spering
In: Journal of Neuroscience, vol. 42, no. 3, pp. 487–499, 2021.
Parkinson's disease (PD) is a neurodegenerative disease that includes motor impairments, such as tremor, bradykinesia, and postural instability. Although eye movement deficits are commonly found in saccade and pursuit tasks, preservation of oculo- motor function has also been reported. Here we investigate specific task and stimulus conditions under which oculomotor function in PD is preserved. Sixteen PD patients and 18 healthy, age-matched controls completed a battery of movement tasks that included stationary or moving targets eliciting reactive or deliberate eye movements: pro-saccades, anti-saccades, visually guided pursuit, and rapid go/no-go manual interception. Compared with controls, patients demonstrated systematic impairments in tasks with stationary targets: pro-saccades were hypometric and anti-saccades were incorrectly initiated to- ward the cued target in ;35% of trials compared with 14% errors in controls. In patients, task errors were linked to short la- tency saccades, indicating abnormalities in inhibitory control. However, patients' eye movements in response to dynamic targets were relatively preserved. PD patients were able to track and predict a disappearing moving target and make quick go/no-go decisions as accurately as controls. Patients' interceptive hand movements were slower on average but initiated ear- lier, indicating adaptive processes to compensate for motor slowing. We conclude that PD patients demonstrate stimulus and task dependency of oculomotor impairments, and we propose that preservation of eye and hand movement function in PD is linked to a separate functional pathway through the superior colliculus-brainstem loop that bypasses the fronto-basal ganglia network. Our results demonstrate that studying oculomotor and hand movement function in PD can support disease diagno- sis and further our understanding of disease progression and dynamics.
Markus Frey; Matthias Nau; Christian F. Doeller
Magnetic resonance-based eye tracking using deep neural networks Journal Article
In: Nature Neuroscience, vol. 24, no. 12, pp. 1772–1779, 2021.
Viewing behavior provides a window into many central aspects of human cognition and health, and it is an important variable of interest or confound in many functional magnetic resonance imaging (fMRI) studies. To make eye tracking freely and widely available for MRI research, we developed DeepMReye, a convolutional neural network (CNN) that decodes gaze position from the magnetic resonance signal of the eyeballs. It performs cameraless eye tracking at subimaging temporal resolution in held-out participants with little training data and across a broad range of scanning protocols. Critically, it works even in existing datasets and when the eyes are closed. Decoded eye movements explain network-wide brain activity also in regions not associated with oculomotor function. This work emphasizes the importance of eye tracking for the interpretation of fMRI results and provides an open source software solution that is widely applicable in research and clinical settings.
Lee Friedman; Timothy Hanson; Dillon Lohr; Oleg V. Komogortsev
In: Journal of Eye Movement Research, vol. 14, no. 3, pp. 2, 2021.
Typically, the position error of an eye-tracking device is measured as the distance of the eye-position from the target position in two-dimensional space (angular offset). Accuracy is the mean angular offset. The mean is a highly interpretable measure of central tendency if the underlying error distribution is unimodal and normal. However, in the context of an underlying multimodal distribution, the mean is less interpretable. We will present evidence that the majority of such distributions are multimodal. Only 14.7% of fixation angular offset distributions were unimodal, and of these, only 11.5% were normally distributed. (Of the entire dataset, 1.7% were unimodal and normal.) This multimodality is true even if there is only a single, continuous tracking fixation segment per trial. We present several ap-proaches to measure accuracy in the face of multimodality. We also address the role of fixation drift in partially explaining multimodality.
Lee Friedman; Oleg V Komogortsev
In: Journal of Eye Movement Research, vol. 14, no. 3, pp. 4, 2021.
This paper is a follow-on to our earlier paper (Friedman, Lohr, Hanson, & Komogortsev, 2021), which focused on the multimodality of angular offsets. This paper applies the same analysis to the measurement of spatial precision. Following the literature, we refer these measurements as estimates of device precision, but, in fact, subject characteristics clearly affect the measurements. One typical measure of the spatial precision of an eye-tracking device is the standard deviation (SD) of the position signals (horizontal and vertical) during a fixation. The SD is a highly interpretable measure of spread if the underlying error distri- bution is unimodal and normal. However, in the context of an underlying multimodal dis- tribution, the SD is less interpretable. We will present evidence that the majority of such distributions are multimodal (68-70% strongly multimodal). Only 21-23% of position dis- tributions were unimodal. We present an alternative method for measuring precision that is appropriate for both unimodal and multimodal distributions. This alternative method pro- duces precision estimates that are substantially smaller than classic measures. We present illustrations of both unimodality and multimodality with either drift or a microsaccade pre- sent during fixation. At present, these observations apply only to the EyeLink 1000, and the subjects evaluated herein.
Virginia T. Gallagher; Prianka Murthy; Jane Stocks; Brian Vesci; Jeffrey Mjaanes; Yufen Chen; Hans C. Breiter; Cynthia LaBella; Amy A. Herrold; James L. Reilly
In: Neurotrauma Reports, vol. 2, no. 1, pp. 440–452, 2021.
Although neuroimaging studies of collision (COLL) sport athletes demonstrate alterations in brain structure and function from pre-to post-season, reliable tools to detect behavioral/cognitive change relevant to functional networks associated with participation in collision sports are lacking. This study evaluated the use of eye-movement testing to detect change in cognitive and sensorimotor processing among male club collegiate athletes after one season of participation in collision sports of variable exposure. We predicted that COLL (High Dose [hockey]
Agostino Gibaldi; Noah C. Benson; Martin S. Banks
In: Proceedings of the National Academy of Sciences, vol. 118, no. 7, pp. e2015651118, 2021.
In mammals with frontal eyes, optic-nerve fibers from nasal retina project to the contralateral hemisphere of the brain, and fibers from temporal retina project ipsilaterally. The division between crossed and uncrossed projections occurs at or near the vertical meridian. If the division was precise, a problem would arise. Small objects near midline, but nearer or farther than current fixation, would produce signals that travel to opposite hemispheres, making the binocular disparity of those objects difficult to compute. However, in species that have been studied, the division is not precise. Rather, there are overlapping crossed and uncrossed projections such that some fibers from nasal retina project ipsilaterally as well as contralaterally and some from temporal retina project contralaterally as well as ipsilaterally. This increases the probability that signals from an object near vertical midline travel to the same hemisphere, thereby aiding disparity estimation. We investigated whether there is a deficit in binocular vision near the vertical meridian in humans and found no evidence for one. We also investigated the effectiveness of the observed decussation pattern, quantified from anatomical data in monkeys and humans. We used measurements of naturally occurring disparities in humans to determine disparity distributions across the visual field. We then used those distributions to calculate the probability of natural disparities transmitting to the same hemisphere, thereby aiding disparity computation. We found that the pattern of overlapping projections is quite effective. Thus, crossed and uncrossed projections from the retinas are well designed for aiding disparity estimation and stereopsis.
Agostino Gibaldi; Silvio P. Sabatini
In: Behavior Research Methods, vol. 53, no. 1, pp. 167–187, 2021.
Saccades are rapid ballistic eye movements that humans make to direct the fovea to an object of interest. Their kinematics is well defined, showing regular relationships between amplitude, duration, and velocity: the saccadic 'main sequence'. Deviations of eye movements from the main sequence can be used as markers of specific neurological disorders. Despite its significance, there is no general methodological consensus for reliable and repeatable measurements of the main sequence. In this work, we propose a novel approach for standard indicators of oculomotor performance. The obtained measurements are characterized by high repeatability, allowing for fine assessments of inter- and intra-subject variability, and inter-ocular differences. The designed experimental procedure is natural and non-fatiguing, thus it is well suited for fragile or non-collaborative subjects like neurological patients and infants. The method has been released as a software toolbox for public use. This framework lays the foundation for a normative dataset of healthy oculomotor performance for the assessment of oculomotor dysfunctions.
In: Journal of Vision, vol. 21, no. 1, pp. 1–19, 2021.
The oculomotor system makes use of an integration of previous stimulus velocities (the prior) and current sensory inputs to adjust initial eye speeds. The present study extended this research by investigating the roles of different retinal or extra-retinal signals for this process. To test for this, participants viewed movement sequences that all ended with the same test trial. Earlier in the sequence, the prior was manipulated by presenting targets that either had different velocities, different starting positions, or target movements designed to elicit differential oculomotor behavior (tracked with or without additional corrective saccades). Additionally, these prior targets could vary in terms of contrast to manipulate reliability. When the velocity of prior trials differed from test trials, the reliability-weighted integration of prior information was replicated. When the prior trials differed in starting position, significant effects on subsequent oculomotor behavior were only observed for the reliable target. Although there were also differences in eye velocity across the different manipulations, they could not explain the observed reliability-weighted integration. When comparing the same physical prior trials but tracked with additional corrective saccades, the eye velocity in the test trial also differed systematically (slower for forward saccades, and faster for backward saccades). The direction of the observed effect contradicts the expectations based on perceived speed and eye velocity, but can be predicted by a combination of retinal velocity and position error signals. Together, these results suggest that general fluctuations in eye velocity as well as retinal error signals are related to oculomotor behavior in subsequent trials.
Doria M. Gold; John-Ross Rizzo; Yuen Shan Christine Lee; Amanda Childs; Todd E. Hudson; John Martone; Yuka K. Matsuzawa; Felicia Fraser; Joseph H. Ricker; Weiwei Dai; Ivan Selesnick; Laura J. Balcer; Steven L. Galetta; Janet C. Rucker
In: Brain Sciences, vol. 11, pp. 1571, 2021.
(1) Background: The King-Devick (KD) rapid number naming test is sensitive for concussion diagnosis, with increased test time from baseline as the outcome measure. Eye tracking during KD performance in concussed individuals shows an association between inter-saccadic interval (ISI) (the time between saccades) prolongation and prolonged testing time. This pilot study retrospectively assesses the relation between ISI prolongation during KD testing and cognitive performance in persistently-symptomatic individuals post-concussion. (2) Results: Fourteen participants (median age 34 years; 6 women) with prior neuropsychological assessment and KD testing with eye tracking were included. KD test times (72.6 ± 20.7 s) and median ISI (379.1 ± 199.1 msec) were prolonged compared to published normative values. Greater ISI prolongation was associated with lower scores for processing speed (WAIS-IV Coding
Henry Griffith; Dillon Lohr; Evgeny Abdulin; Oleg Komogortsev
In: Scientific Data, vol. 8, no. 1, pp. 1–9, 2021.
This manuscript presents GazeBase, a large-scale longitudinal dataset containing 12,334 monocular eye-movement recordings captured from 322 college-aged participants. Participants completed a battery of seven tasks in two contiguous sessions during each round of recording, including a – (1) fixation task, (2) horizontal saccade task, (3) random oblique saccade task, (4) reading task, (5/6) free viewing of cinematic video task, and (7) gaze-driven gaming task. Nine rounds of recording were conducted over a 37 month period, with participants in each subsequent round recruited exclusively from prior rounds. All data was collected using an EyeLink 1000 eye tracker at a 1,000 Hz sampling rate, with a calibration and validation protocol performed before each task to ensure data quality. Due to its large number of participants and longitudinal nature, GazeBase is well suited for exploring research hypotheses in eye movement biometrics, along with other applications applying machine learning to eye movement signal analysis. Classification labels produced by the instrument's real-time parser are provided for a subset of GazeBase, along with pupil area.
Palak Gupta; Sinem Beylergil; Jordan Murray; Jonathan Jacobs; Camilla Kilbane; Aasef G. Shaikh; Fatema F. Ghasia
In: Journal of Neuro-Ophthalmology, vol. 41, no. 4, pp. 442–451, 2021.
Synchronous movements of the 2 eyes in the opposite direction, disconjugate movements such as vergence, facilitate depth perception. The vergence eye movements are affected in Parkinson disease (PD). Visual blur (accommodation) and fusion (retinal disparity) are important triggers for the vergence. The neural circuit responsible for blur-driven and disparity-driven vergence is tightly coupled. We investigated the effect of PD on these 2 vergence paradigms. In the experiment involving 14 patients with PD and 6 healthy controls, substantial differences between blur-driven and disparity-driven vergence were found. The gain (ratio of actual vs desired eye movements) was reduced in patients with PD in case of disparity-driven vergence but not in blur-driven vergence. The latency of disparity-driven vergence onset was significantly longer for patients with PD compared with healthy controls. Four strategies were used to drive disparity-driven vergence: a) pure disconjugate vergence, b) conjugate saccadic movements, c) disconjugate vergence followed by saccadic movements, and d) conjugate saccades followed by disconjugate vergence movements. Blur-driven vergence had only 2 strategies: a) conjugate saccades followed by disconjugate vergence and b) conjugate saccadic movements only. The results are consistent with the prediction that PD primarily affects disparity-driven vergence, but there are some effects on the strategies to execute blur-driven vergence. We speculate that the deep cerebellar nuclei and the supraoculomotor area of the midbrain that carry the disparity-driven and blur-driven vergence are affected in PD. It is possible to modulate their function through projections to the subthalamic nuclei.
Palak Gupta; Sinem Beylergil; Jordan Murray; Camilla Kilbane; Fatema F. Ghasia; Aasef G. Shaikh
In: Journal of Neural Engineering, vol. 18, no. 4, pp. 0460a5, 2021.
Objective: Parkinson's disease (PD) frequently affects vergence eye movements interfering with the perception of depth and dimensionality critical for mitigating falls. We examined neural strategies that compensate for abnormal vergence and their mechanistic underpinning in PD. Approach: The a priori hypothesis was that impaired vergence is compensated by incorporating rapid eye movements (saccades) to accomplish gaze shifts at different depths. Our experiments examined the hypothesis by simulating biologically plausible computational models of saccade-vergence interactions in PD and validating predictions in the actual patient data. Main results: We found four strategies to accomplish 3D gaze shift; pure vergence eye movements, pure saccadic eye movements, combinations of vergence followed by a saccade, and combination of saccade followed by vergence. The gaze shifting strategy of the two eyes was incongruent in PD. The latency of vergence was prolonged, and it was more so when the saccades preceded the vergence or when the saccades only made 3D gaze shift. Computational models predicted at least two possible mechanisms triggering saccades along with vergence. One is based on the lack of foveal accuracy when the vergence gain is suboptimal. The second mechanism reflects the noise in the gating mechanism, the omnipause neurons, for vergence and saccades. None of the two model predictions alone were completely supported by the patient data. However, a combined model incorporating both abnormal vergence velocity gain and impaired gating accurately simulated the results from PD patients. Significance: The combined strategy is biologically plausible for two reasons: (a) The basal ganglia that is prominently affected in PD projects to the vergence velocity neurons in the midbrain via the cerebellum. The projection directly affects the vergence velocity gain. (b) The basal ganglia, via superior colliculus, influences the pattern of omnipause neuronal activity. Abnormal basal ganglia activity may introduce noise in the omnipause neurons.
Rakesh Nanjappa; Robert M. McPeek
In: Journal of Vision, vol. 21, no. 2, pp. 1–15, 2021.
While aiming and shooting, we make tiny eye movements called microsaccades that shift gaze between task-relevant objects within a small region of the visual field. However, in the brief period before pressing the trigger, microsaccades are suppressed. This might be due to the lack of a requirement to shift gaze as the retinal images of the two objects begin to overlap on the fovea. Alternatively, we might actively suppress microsaccades to prevent any disturbances in visual perception caused by microsaccades around the time of their occurrence and their subsequent effect on shooting performance. In this study we looked at microsaccade rates while participants performed a simulated shooting task under two conditions: a normal condition in which they moved their eyes freely, and an eccentric condition in which they maintained gaze on a fixed target while performing the shooting task at 5° eccentricity. As expected, microsaccade rate dropped near the end of the task in the normal viewing condition. However, we also found the same decrease for the eccentric condition in which microsaccades did not shift gaze between the task objects. Microsaccades are also produced in response to shifts in covert attention. To test whether disengagement of covert attention from the eccentric shooting location caused the drop in microsaccade rate, we monitored the location of participants' spatial attention by using a Rapid Serial Visual Presentation (RSVP) task simultaneously at a location opposite to the shooting task. Target letter detection at the RSVP location did not improve during the drop in microsaccade rate, suggesting that covert attention was maintained at the shooting task location.We conclude that in addition to their usual gaze-shifting function, microsaccades during fine-acuity tasks might be modulated by cognitive processes other than spatial attention.
Jenny A. Nij Bijvank; Esther Sánchez Aliaga; Lisanne J. Balk; Danko Coric; Indran Davagnanam; H. Stevie Tan; Bernard M. J. Uitdehaag; Laurentius J. Rijn; Axel Petzold
In: European Journal of Neurology, vol. 28, no. 5, pp. 1617–1626, 2021.
Background and purpose: The clinico-radiological paradox in multiple sclerosis (MS) is well recognized, relevant and yet poorly understood. The suitability of an in vivo model for the clinico-radiological paradox was tested, using internuclear ophthalmoplegia (INO) and the medial longitudinal fasciculus (MLF). Methods: In this cross-sectional study lesions of the MLF were rated by an experienced MS neuroradiologist blinded to all other information. The presence of an INO was objectively determined by a validated infrared oculography protocol (DEMoNS). Clinical information, including the National Eye Institute Visual Function Questionnaire, was obtained. Results: This study included 202 patients with MS. The clinico-radiological paradox occurred in 50 patients (25%). This consisted of 45 patients having an INO without an MLF lesion and five patients with an MLF lesion but without an INO. The visual function overall score was related to the presence of an INO (p = 0.016), but not to MLF lesions seen on magnetic resonance imaging (MRI) (p = 0.207). A consensus list of potential causes for the clinico-radiological paradox was compiled and the MRI images were deposited in a repository. Conclusion: This study provides an objective and quantitative model to investigate the clinico-radiological paradox. Our data suggest that pathology of the MLF is more frequently detected and more clinically relevant by infrared oculography than by MLF lesion rating on MRI.
Marcus Nyström; Diederick C. Niehorster; Richard Andersson; Ignace Hooge
In: Behavior Research Methods, vol. 53, no. 1, pp. 335–353, 2021.
Due to its reported high sampling frequency and precision, the Tobii Pro Spectrum is of potential interest to researchers who want to study small eye movements during fixation. We test how suitable the Tobii Pro Spectrum is for research on microsaccades by computing data-quality measures and common properties of microsaccades and comparing these to the currently most used system in this field: the EyeLink 1000 Plus. Results show that the EyeLink data provide higher RMS precision and microsaccade rates compared with data acquired with the Tobii Pro Spectrum. However, both systems provide microsaccades with similar directions and shapes, as well as rates consistent with previous literature. Data acquired at 1200 Hz with the Tobii Pro Spectrum provide results that are more similar to the EyeLink, compared to data acquired at 600 Hz. We conclude that the Tobii Pro Spectrum is a useful tool for researchers investigating microsaccades.
Jessie R. Oldham; William P. Meehan; David R. Howell
In: Journal of Sport and Health Science, vol. 10, no. 2, pp. 138–144, 2021.
Purpose: The purpose of the study was to (1) examine the relationship between self-reported symptoms and concussion-related eye tracking impairments, and (2) compare gait performance between (a) adolescents with a concussion who have normal eye tracking, (b) adolescents with a concussion who have abnormal eye tracking, and (c) healthy controls. Methods: A total of 30 concussed participants (age: 14.4 ± 2.2 years, mean ± SD, 50% female) and 30 controls (age: 14.2 ± 2.2 years, 47% female) completed eye tracking and gait assessments. The BOX score is a metric of pupillary disconjugacy, with scores <10 classified as normal and ≥10 abnormal. Symptoms were collected using the Post-Concussion Symptom Scale (PCSS), and gait speed was measured with triaxial inertial measurement units. We conducted a linear regression to examine the relationship between PCSS and BOX scores and a two-way mixed effects analysis of variance to examine the effect of group (abnormal BOX, normal BOX, and healthy control) on single- and dual-task gait speed. Results: There was a significant association between total PCSS score and BOX score in the concussion group ($beta$ = 0.16
Yumie Ono; Takahiro Niida; Yuma Shinomiya; Kenji Suzuki; Naoto Hara; Yasuhiko Azegami; Taeko Sato; Chigusa Mimori; Hideo Shimoizumi
In: Advanced Biomedical Engineering, vol. 10, pp. 70–79, 2021.
Visually guided saccadic eye movement has been considered a promising screening tool for cognitive function because of its simple and objective nature. However, its application to young children, especially those with developmental disorders, is limited due to the lack of sustained attention required to complete the measurement using the traditional electrophysiological protocol. We have previously reported that saccades can be reliably evaluated in typically developing young children using an eye tracker, which allows non-contact measurement of eye movement with a sufficiently short preparation time. Using the eye tracker system combined with an in-house developed analysis software, we investigated the changes in saccadic behavior between typically developing children (n = 30) and children with developmental disorders (attention-deficit/hyperactivity disorder [ADHD] and autism spectrum disorder [ASD]