EyeLink Clinical and Oculomotor Eye-Tracking Publications
EyeLink clinical and oculomotor research publications up until 2024 (with some early 2025s) 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!
2025 |
Xin Wang; Lizhou Fan; Haiyun Li; Xiaochan Bi; Wenjing Jiang; Xin Ma Skip-AttSeqNet: Leveraging skip connection and attention-driven Seq2seq model to enhance eye movement event detection in Parkinson's disease Journal Article In: Biomedical Signal Processing and Control, vol. 99, pp. 1–17, 2025. @article{Wang2025a,To address the limitations of traditional algorithms in detecting eye movement events, particularly in Parkinson's disease (PD) patients, this study introduces Skip-AttSeqNet. It presents an innovative approach combining skip-connected, one-dimensional convolutional neural networks with an attention-enhanced, bidirectional long short-term memory network. This hybrid architecture significantly advances smooth pursuit (SP) event detection, as evidenced by its performance on both the GazeCom dataset and a unique dataset of PD patient eye movements. Key innovations in this work include the utilization of skip connections and attention mechanisms, along with optimized training–validation set division, collectively enhancing the model's accuracy while mitigating overfitting. Skip-AttSeqNet outperforms existing algorithms, achieving a 3.2% higher sample-level F1 score and a notable 6.2% increase in event-level F1 scores for SP detection. Furthermore, we established a smooth-pursuit experimental paradigm and identified significant differences in saccade and SP features between PD patients and healthy older adults through statistical analysis using the Mann–Whitney test. These findings underscore the potential of eye movement metrics as biomarkers for PD, thereby not only strengthening PD diagnosis but also enriching the intersection of computer vision and biomedical research domains. |
Jing Zhu; Yuanlong Li; Changlin Yang; Hanshu Cai; Xiaowei Li; Bin Hu Transformer-based fusion model for mild depression recognition with EEG and pupil area signals Journal Article In: Medical and Biological Engineering & Computing, pp. 1–17, 2025. @article{Zhu2025,Early detection and treatment are crucial for the prevention and treatment of depression; compared with major depression, current researches pay less attention to mild depression. Meanwhile, analysis of multimodal biosignals such as EEG, eye movement data, and magnetic resonance imaging provides reliable technical means for the quantitative analysis of depression. However, how to effectively capture relevant and complementary information between multimodal data so as to achieve efficient and accurate depression recognition remains a challenge. This paper proposes a novel Transformer-based fusion model using EEG and pupil area signals for mild depression recognition. We first introduce CSP into the Transformer to construct single-modal models of EEG and pupil data and then utilize attention bottleneck to construct a mid-fusion model to facilitate information exchange between the two modalities; this strategy enables the model to learn the most relevant and complementary information for each modality and only share the necessary information, which improves the model accuracy while reducing the computational cost. Experimental results show that the accuracy of the EEG and pupil area signals of single-modal models we constructed is 89.75% and 84.17%, the precision is 92.04% and 95.21%, the recall is 89.5% and 71%, the specificity is 90% and 97.33%, the F1 score is 89.41% and 78.44%, respectively, and the accuracy of mid-fusion model can reach 93.25%. Our study demonstrates that the Transformer model can learn the long-term time-dependent relationship between EEG and pupil area signals, providing an idea for designing a reliable multimodal fusion model for mild depression recognition based on EEG and pupil area signals. |
Andrés Torres Sánchez; Marie Dawant; Venethia Danthine; Inci Cakiroglu; Roberto Santalucia; Enrique Ignacio Germany Morrison; Antoine Nonclercq; Riëm El Tahry VNS-induced dose-dependent pupillary response in refractory epilepsy Journal Article In: Clinical Neurophysiology, vol. 171, pp. 67–75, 2025. @article{TorresSanchez2025,Purpose: The Locus Coeruleus (LC) plays a vital role by releasing norepinephrine, which contributes to the antiepileptic effects of Vagus Nerve Stimulation (VNS). LC activity also influences pupil dilation. Investigating VNS dose-dependent Pupillary Dilation Response (PDR) may provide novel neurophysiological insights into therapeutic response and allow for an objective and personalized optimization of stimulation parameters. Methods: Fourteen VNS-implanted patients (9 responders, 5 non-responders) treated for at least 6 months were retrospectively recruited. VNS intensities were adjusted from 0.25 mA to 2.25 mA, or to the highest tolerable level. Concurrently, we tracked pupil size in the left eye and gathered patients' subjective perception scores. Individual curve fitting was used to explore the relationship between VNS intensity and PDR. Results: PDR increased with stimulation intensity, particularly in responders. In 6 patients, an inverted U-shaped relationship between intensity and PDR was observed 2–3 s after stimulation onset. A significant interaction was found between VNS intensity and responder status, independent of subjective perception. Conclusions: VNS induces a dose-dependent PDR, which differs between responders and non-responders. In nearly half the patients, the dose–response relationship was characterized by an inverted U-shape with a maximal VNS effect. Significance: We propose VNS-induced PDR as a novel biomarker of VNS response. |
Duncan T. Tulimieri; Amelia Decarie; Tarkeshwar Singh; Jennifer A. Semrau Impairments in proprioceptively-referenced limb and eye movements in chronic stroke Journal Article In: Neurorehabilitation and Neural Repair, vol. 39, no. 1, pp. 47 –57, 2025. @article{Tulimieri2025,Background: Upper limb proprioceptive impairments are common after stroke and affect daily function. Recent work has shown that stroke survivors have difficulty using visual information to improve proprioception. It is unclear how eye movements are impacted to guide action of the arm after stroke. Here, we aimed to understand how upper limb proprioceptive impairments impact eye movements in individuals with stroke. Methods: Control (N = 20) and stroke participants (N = 20) performed a proprioceptive matching task with upper limb and eye movements. A KINARM exoskeleton with eye tracking was used to assess limb and eye kinematics. The upper limb was passively moved by the robot and participants matched the location with either an arm or eye movement. Accuracy was measured as the difference between passive robot movement location and active limb matching (Hand-End Point Error) or active eye movement matching (Eye-End Point Error). Results: We found that individuals with stroke had significantly larger Hand (2.1×) and Eye-End Point (1.5×) Errors compared to controls. Further, we found that proprioceptive errors of the hand and eye were highly correlated in stroke participants (r =.67 |
Carla A. Wall; Caitlin Hudac; Kelsey Dommer; Beibin Li; Adham Atyabi; Claire Foster; Quan Wang; Erin Barney; Yeojin Amy Ahn; Minah Kim; Monique Mahony; Raphael Bernier; Pamela Ventola; Frederick Shic Preserved but un-sustained responses to bids for dyadic engagement in school-age children with Autism Journal Article In: Journal of Autism and Developmental Disorders, pp. 1–9, 2025. @article{Wall2025,Purpose: Dynamic eye-tracking paradigms are an engaging and increasingly used method to study social attention in autism. While prior research has focused primarily on younger populations, there is a need for developmentally appropriate tasks for older children. Methods: This study introduces a novel eye-tracking task designed to assess school-aged children's attention to speakers involved in conversation. We focused on a primary outcome of attention to speakers' faces during conversation between three actors and during emulated bids for dyadic engagement (dyadic bids). Results: In a sample of 161 children (78 autistic, 83 neurotypical), children displayed significantly lower overall attention to faces compared to their neurotypical peers (p <.0001). Contrary to expectations, both groups demonstrated preserved attentional responses to dyadic bids, with no significant group differences. However, a divergence was observed following the dyadic bid: neurotypical children showed more attention to other conversational agents' faces than autistic children (p =.017). Exploratory analyses in the autism group showed that reduced attention to faces was associated with greater autism features during most experimental conditions. Conclusion: These findings highlight key differences in how autistic and neurotypical children engage with social cues, particularly in dynamic and interactive contexts. The preserved response to dyadic bids in autism, alongside the absence of post-bid attentional shifts, suggests nuanced and context-dependent social attention mechanisms that should be considered in future research and intervention strategies. |
Carla A. Wall; Frederick Shic; Elizabeth A. Will; Quan Wang; Jane E. Roberts Similar gap-overlap profiles in children with fragile x syndrome and IQ-matched autism Journal Article In: Journal of Autism and Developmental Disorders, vol. 55, pp. 891–903, 2025. @article{Wall2025a,Purpose: Fragile X syndrome (FXS) is a single-gene disorder characterized by moderate to severe cognitive impairment and a high association with autism spectrum disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD). Atypical visual attention is a feature of FXS, ASD, and ADHD. Thus, studying early attentional patterns in young children with FXS can offer insight into early emerging neurocognitive processes underlying challenges and contribute to our understanding of common and unique features of ASD and ADHD in FXS. Methods: The present study examined visual attention indexed by the gap-overlap paradigm in children with FXS (n = 39) compared to children with ASD matched on intellectual ability and age (n = 40) and age-matched neurotypical controls (n = 34). The relationship between gap-overlap performance and intellectual ability, ASD, and ADHD across groups was characterized. Saccadic reaction times (RT) were collected across baseline, gap, and overlap conditions. Results: Results indicate no group differences in RT for any conditions. However, RT of the ASD and NT groups became slower throughout the experiment whereas RT of the FXS group did not change, suggesting difficulties in habituation for the FXS group. There was no relationship between RT and intellectual ability, ADHD, or ASD symptoms in the FXS and ASD groups. In the NT group, slower RT was related to elevated ADHD symptoms only. Conclusion: Taken together, findings suggest that the social attention differences documented in FXS and ASD may be due to other cognitive factors, such as reward or motivation, rather than oculomotor control of visual attention. |
Alexander J. Shackman; Jason F. Smith; Ryan D. Orth; Christina L. G Savage; Paige R. Didier; Julie M. Mccarthy; Melanie E. Bennett; Jack J. Blanchard Blunted ventral striatal reactivity to social reward is associated with more severe motivation and pleasure deficits in psychosis Journal Article In: Schizophrenia Bulletin, pp. 1–36, 2025. @article{Shackman2025,Background and Hypothesis: Among individuals living with psychotic disorders, social impairment is common, debilitating, and challenging to treat. While the roots of this impairment are undoubtedly complex, converging lines of evidence suggest that social motivation and pleasure (MAP) deficits play a central role. Yet most neuroimaging studies have focused on monetary rewards, precluding deci- sive inferences. Study Design: Here we leveraged parallel social and monetary incentive delay functional magnetic resonance imaging paradigms to test whether blunted reactivity to social incentives in the ventral striatum—a key component of the distributed neural circuit mediating appetitive motivation and hedonic pleasure—is associated with more severe MAP symptoms in a transdiagnostic adult sample enriched for psychosis. To maximize ecological validity and translational relevance, we capitalized on naturalistic audiovisual clips of an established social partner expressing positive feedback. Study Results: Although both paradigms robustly engaged the ventral striatum, only reactivity to social incentives was associated with clinician-rated MAP deficits. This association remained significant when controlling for other symptoms, binary diagnostic status, or striatal reactivity to monetary incentives. Follow-up analyses suggested that this association predominantly reflects diminished activation during the presentation of social reward. Conclusions: These observations provide a neurobiologically grounded framework for conceptualizing the social-anhedonia symptoms and social impairments that characterize many individuals living with psychotic disorders and underscore the need to develop targeted intervention strategies. |
Patrick W. Stroman; Roland Staud; Caroline F. Pukall In: PLoS ONE, vol. 20, no. 1, pp. 1–25, 2025. @article{Stroman2025,Altered neural signaling in fibromyalgia syndrome (FM) was investigated with functional magnetic resonance imaging (fMRI). We employed a novel fMRI network analysis method, Structural and Physiological Modeling (SAPM), which provides more detailed information than previous methods. The study involved brain fMRI data from participants with FM (N = 22) and a control group (HC |
Lukas Suveg; Tanvi Thakkar; Emily Burg; Shelly P. Godar; Daniel Lee; Ruth Y. Litovsky The relationship between spatial release from masking and listening effort among cochlear implant users with single-sided deafness Journal Article In: Ear & Hearing, pp. 1–16, 2025. @article{Suveg2025,Objectives: To examine speech intelligibility and listening effort in a group of patients with single-sided deafness (SSD) who received a cochlear implant (CI). There is limited knowledge on how effectively SSD-CI users can integrate electric and acoustic inputs to obtain spatial hearing benefits that are important for navigating everyday noisy environments. The present study examined speech intelligibility in quiet and noise simultaneously with measuring listening effort using pupillometry in individuals with SSD before, and 1 year after, CI activation. The study was designed to examine whether spatial separation between target and interfering speech leads to improved speech understanding (spatial release from masking [SRM]), and is associated with a decreased effort (spatial release from listening effort [SRE]) measured with pupil dilation (PPD). Design: Eight listeners with adult-onset SSD participated in two visits: (1) pre-CI and (2) post-CI (1 year after activation). Target speech consisted of Electrical and Electronics Engineers sentences and masker speech consisted of AzBio sentences. Outcomes were measured in three target-masker configurations with the target fixed at 0° azimuth: (1) quiet, (2) co-located target/maskers, and (3) spatially separated (±90° azimuth) target/maskers. Listening effort was quantified as change in peak proportional PPD on the task relative to baseline dilation. Participants were tested in three listening modes: acoustic-only, CI-only, and SSD-CI (both ears). At visit 1, the acoustic-only mode was tested in all three target-masker configurations. At visit 2, the acoustic-only and CI-only modes were tested in quiet, and the SSD-CI listening mode was tested in all three target-masker configurations. Results: Speech intelligibility scores in quiet were at the ceiling for the acoustic-only mode at both visits, and in the SSD-CI listening mode at visit 2. In quiet, at visit 2, speech intelligibility scores were significantly worse in the CI-only listening modes than in all other listening modes. Comparing SSD-CI listening at visit 2 with pre-CI acoustic-only listening at visit 1, speech intelligibility scores for co-located and spatially separated configurations showed a trend toward improvement (higher scores) that was not significant. However, speech intelligibility was significantly higher in the separated compared with the co-located configuration in acoustic-only and SSD-CI listening modes, indicating SRM. PPD evoked by speech presented in quiet was significantly higher with CI-only listening at visit 2 compared with acoustic-only listening at visit 1. However, there were no significant differences between co-located and spatially separated configurations on PPD, likely due to the variability among this small group of participants. There was a negative correlation between SRM and SRE, indicating that improved speech intelligibility with spatial separation of target and masker is associated with a greater decrease in listening effort on those conditions. Conclusions: The small group of patients with SSD-CI in the present study demonstrated improved speech intelligibility from spatial separation of target and masking speech, but PPD measures did not reveal the effects of spatial separation on listening effort. However, there was an association between the improvement in speech intelligibility (SRM) and the reduction in listening effort (SRE) from spatial separation of target and masking speech. |
Juyoen Hur; Rachael M. Tillman; Hyung Cho Kim3; Paige Didier; Allegra S. Anderson; Samiha Islam; Melissa D. Stockbridge; Andres De Los Reyes; Kathryn A. DeYoung; Jason F. Smith; Alexander J. Shackman In: Journal of Psychopathology and Clinical Science, vol. 134, no. 1, pp. 41–56, 2025. @article{Hur2025,Social anxiety-which typically emerges in adolescence-lies on a continuum and, when extreme, can be devastating. Socially anxious individuals are prone to heightened fear, anxiety, and the avoidance of contexts associated with potential social scrutiny. Yet most neuroimaging research has focused on acute social threat. Much less attention has been devoted to understanding the neural systems recruited during the uncertain anticipation of potential encounters with social threat. Here we used a novel fMRI paradigm to probe the neural circuitry engaged during the anticipation and acute presentation of threatening faces and voices in a racially diverse sample of 66 adolescents selectively recruited to encompass a range of social anxiety and enriched for clinically significant levels of distress and impairment. Results demonstrated that adolescents with more severe social anxiety symptoms experience heightened distress when anticipating encounters with social threat, and reduced discrimination of uncertain social threat and safety in the bed nucleus of the stria terminalis (BST), a key division of the central extended amygdala (EAc). Although the EAc-including the BST and central nucleus of the amygdala-was robustly engaged by the acute presentation of threatening faces and voices, the degree of EAc engagement was unrelated to the severity of social anxiety. Together, these observations provide a neurobiologically grounded framework for conceptualizing adolescent social anxiety and set the stage for the kinds of prospective-longitudinal and mechanistic research that will be necessary to determine causation and, ultimately, to develop improved interventions for this often-debilitating illness. |
Tristan Jurkiewicz; Audrey Vialatte; Yaffa Yeshurun; Laure Pisella Attentional modulation of peripheral pointing hypometria in healthy participants: An insight into optic ataxia? Journal Article In: Neuropsychologia, vol. 208, pp. 1–12, 2025. @article{Jurkiewicz2025,Damage to the superior parietal lobule and intraparietal sulcus (SPL-IPS) causes optic ataxia (OA), characterized by pathological gaze-centered hypometric pointing to targets in the affected peripheral visual field. The SPL-IPS is also involved in covert attention. Here, we investigated the possible link between attention and action. This study investigated the effect of attention on pointing performance in healthy participants and two OA patients. In invalid trials, targets appeared unpredictably across different visual fields and eccentricities. Valid trials involved cued targets at specific locations. The first experiment used a central cue with 75% validity, the second used a peripheral cue with 50% validity. The effect of attention on pointing variability (noise) or time was expected as a confirmation of cueing efficiency. Critically, if OA reflects an attentional deficit, then healthy participants, in the invalid condition (without attention), were expected to produce the gaze-centered hypometric pointing bias characteristic of OA. Results: revealed main effects of validity on pointing biases in all participants with central predictive cueing, but not with peripheral low predictive cueing. This suggests that the typical underestimation of visual eccentricity in OA (visual field effect) at least partially results from impaired endogenous attention orientation toward the affected visual field. |
Anna R. Knippenberg; Sabrina Yavari; Gregory P. Strauss Negative auditory hallucinations are associated with increased activation of the defensive motivational system in schizophrenia Journal Article In: Schizophrenia Research: Cognition, vol. 39, pp. 1–6, 2025. @article{Knippenberg2025,Auditory hallucinations (AH) are the most common symptom of psychosis. The voices people hear make comments that are benign or even encouraging, but most often voices are threatening and derogatory. Negative AH are often highly distressing and contribute to suicide risk and violent behavior. Biological mechanisms underlying the valence of voices (i.e., positive, negative, neutral) are not well delineated. In the current study, we examined whether AH voice valence was associated with increased activation of the Defensive Motivational System, as indexed by central and autonomic system response to unpleasant stimuli. Data were evaluated from two studies that used a common symptom rating instrument, the Psychotic Symptom Rating Scale (PSY-RATS), to measure AH valence. Participants included outpatients diagnosed with SZ. Tasks included: Study 1: Trier Social Stress Task while heart rate was recorded via electrocardiography (N = 27); Study 2: Passive Viewing Task while participants were exposed to pleasant, unpleasant, and neutral images from the International Affective Picture System (IAPS) library while eye movements, pupil dilation, and electroencephalography were recorded (N = 25). Results indicated that negative voice content was significantly associated with: 1) increased heart rate during an acute social stressor, 2) increased pupil dilation to unpleasant images, 3) higher neural reactivity to unpleasant images, and 4) a greater likelihood of having bottom-up attention drawn to unpleasant stimuli. Findings suggest that negative AH are associated with greater Defensive Motivational System activation in terms of central and autonomic nervous system response. |
Alma Rahimi; Azar Ayaz; Chloe Edgar; Gianna Jeyarajan; Darryl Putzer; Michael Robinson; Matthew Heath; Alma Rahimi; Azar Ayaz; Chloe Edgar; Gianna Jeyarajan; Darryl Putzer; Michael Robinson; Matthew Heath; Feb Sub-symptom Sub-symptom threshold aerobic exercise improves executive function during the early stage of sport-related concussion recovery Journal Article In: Journal of Sports Sciences, pp. 1–14, 2025. @article{Rahimi2025,We examined whether persons with a sport-related concussion (SRC) derive a postexercise executive function (EF) benefit, and whether a putative benefit is related to an exercise-mediated increase in cerebral blood flow (CBF). Participants with an SRC completed the Buffalo Concussion Bike Test to determine the heart rate threshold (HRt) associated with symptom exacerbation and/or voluntary exhaustion. On a separate day, SRC participants – and healthy controls (HC group) – completed 20-min of aerobic exercise at 80% HRt while middle cerebral artery velocity (MCAv) was measured to estimate CBF. The antisaccade task (i.e. saccade mirror-symmetrical to target) was completed pre- and postexercise to evaluate EF. SRC and HC groups showed a comparable exercise-mediated increase in CBF (ps < .001), and both groups elicited a postexercise EF benefit (ps < .001); however, the benefit was unrelated to the magnitude of the MCAv change. Moreover, SRC symptomology was not increased when assessed immediately postexercise and showed a 24 h follow-up benefit. Accordingly, persons with an SRC demonstrated an EF benefit following a single bout of sub-symptom threshold aerobic exercise. Moreover, the exercise intervention did not result in symptom exacerbation and thus demonstrates that a tailored aerobic exercise program may support cognitive and symptom recovery following an SRC. |
Jason F. Rubinstein; Noelia Gabriela Alcalde; Adrien Chopin; Preeti Verghese Oculomotor challenges in macular degeneration impact motion extrapolation Journal Article In: Journal of Vision, vol. 25, no. 1, pp. 1–19, 2025. @article{Rubinstein2025,Macular degeneration (MD), which affects the central visual field including the fovea, has a profound impact on acuity and oculomotor control.We used a motion extrapolation task to investigate the contribution of various factors that potentially impact motion estimation, including the transient disappearance of the target into the scotoma, increased position uncertainty associated with eccentric target positions, and increased oculomotor noise due to the use of a non-foveal locus for fixation and for eye movements. Observers performed a perceptual baseball task where they judged whether the target would intersect or miss a rectangular region (the plate). The target was extinguished before reaching the plate and participants were instructed either to fixate a marker or smoothly track the target before making the judgment.We tested nine eyes of six participants with MD and four control observers with simulated scotomata that matched those of individual participants with MD. Both groups used their habitual oculomotor locus—eccentric preferred retinal locus (PRL) for MD and fovea for controls. In the fixation condition, motion extrapolation was less accurate for controls with simulated scotomata than without, indicating that occlusion by the scotoma impacted the task. In both the fixation and pursuit conditions, MD participants with eccentric preferred retinal loci typically had worse motion extrapolation than controls with a matched artificial scotoma and foveal preferred retinal loci. Statistical analysis revealed occlusion and target eccentricity significantly impacted motion extrapolation in the pursuit condition, indicating that these factors make it challenging to estimate and track the path of a moving target in MD. |
Ting Xun Li; Chi Wen Liang In: Cognitive Therapy and Research, vol. 49, pp. 62–74, 2025. @article{Li2025,Background: Attentional bias modification (ABM) is a computerized treatment for anxiety. Most ABMs using a dot-probe task aim to direct anxious individuals' attention away from threats. Recently, a new ABM approach using a visual search task (i.e., ABM-positive-search) has been developed to facilitate the allocation of attention toward positive stimuli. This study examined the efficacies of two versions of ABM-positive-search in socially anxious individuals. Methods: Eighty-six participants were randomly assigned to the search positive in threat (SP-T; n = 28), search positive in neutral (SP-N; n = 29), or control training (CT) (n = 29) group. All participants completed four training sessions within two weeks. Attentional bias, attentional control, self-report social anxiety, and anxiety responses (i.e., subjective anxiety, psychophysiological reactivity, and gaze behavior) to the speech task were assessed pre-training and post-training. Results: Results showed that ABM-positive-search trainings facilitated disengagement from threats compared to CT. Regardless of group, participants exhibited a reduction in attention allocation to negative feedback during speech. However, only SP-N increased attention allocation to positive feedback. Participants in three groups showed a decrease in subjective anxiety but no changes in psychophysiological reactivity to speech challenge from pre-training to post-training. ABM-positive-search trainings had no beneficial effects on attentional control or self-report social anxiety when compared with CT. Conclusions: The findings do not support the efficacy of ABM-positive-search trainings for social anxiety. |
Selma Lugtmeijer; Aleksandra M. Sobolewska; The Visual Brain Group; Edward H. F. Haan; H. Steven Scholte Visual feature processing in a large stroke cohort: Evidence against modular organization Journal Article In: Brain, pp. 1–11, 2025. @article{Lugtmeijer2025,Mid-level visual processing represents a crucial stage between basic sensory input and higher-level object recognition. The conventional model posits that fundamental visual qualities, such as colour and motion, are processed in specialized, retinotopic brain regions (e.g. V4 for colour, MT/V5 for motion). Using atlas-based lesion–symptom mapping and disconnectome maps in a cohort of 307 ischaemic stroke patients, we examined the neuroanatomical correlates underlying the processing of eight mid-level visual qualities.Contrary to the predictions of the standard model, our results did not reveal consistent relationships between processing impairments and damage to traditionally associated brain regions. Although we validated our methodology by confirming the established relationship between visual field defects and damage to primary visual areas (V1, V2 and V3), we found no reliable evidence linking processing deficits to specific regions in the posterior brain.These findings challenge the traditional modular view of visual processing and suggest that mid-level visual processing might be more distributed across neural networks than previously thought. This supports alternative models where visual maps represent constellations of co-occurring information rather than specific qualities. |
Rotem Mairon; Ohad Ben-shahar The polar saccadic flow model: Re-modeling the center bias from fixations to saccades Journal Article In: Vision Research, vol. 228, pp. 1–12, 2025. @article{Mairon2025,Research indicates that a significant component of human eye movement behavior constitutes a set of consistent biases independent of visual content, the most well-known of which is the central bias. While all prior art focuses on representing saccadic motion and biases in Cartesian retinotopic coordinates, here we propose the Polar Saccadic Flow model, a novel approach for modeling saccades' space-dependent biases in a polar representation. By breaking saccades into orientation and amplitude, the Polar Saccadic Flow model enables more accurate modeling of these components, leading also to a better understanding of the saccadic bias. Moreover, the polar representation also uncovers hitherto unknown patterns and biases in eye movement data, allowing for a more detailed and nuanced analysis of saccadic behavior. These findings have implications for the study of human visual perception, can help to develop more accurate eye movement models, and also may improve eye tracking technologies. |
Kimberly Meier; Simon Warner; Miriam Spering; Deborah Giaschi Poor fixation stability does not account for motion perception deficits in amblyopia Journal Article In: Scientific Reports, vol. 15, no. 1, pp. 1–14, 2025. @article{Meier2025,People with amblyopia show deficits in global motion perception, especially at slow speeds. These observers are also known to have unstable fixation when viewing stationary fixation targets, relative to healthy controls. It is possible that poor fixation stability during motion viewing interferes with the fidelity of the input to motion-sensitive neurons in visual cortex. To probe these mechanisms at a behavioral level, we assessed motion coherence thresholds in adults with amblyopia while measuring fixation stability. Consistent with prior work, participants with amblyopia had elevated coherence thresholds for the slow speed stimuli, but not the fast speed stimuli, using either the amblyopic or the fellow eye. Fixation stability was elevated in the amblyopic eye relative to controls across all motion stimuli, and not selective for conditions on which perceptual deficits were observed. Fixation stability was not related to visual acuity, nor did it predict coherence thresholds. These results suggest that motion perception deficits might not be a result of poor input to the motion processing system due to unstable fixation, but rather due to processing deficits in motion-sensitive visual areas. |
Julian Gutzeit; Lynn Huestegge The impact of the degree of action voluntariness on sense of agency in saccades Journal Article In: Consciousness and Cognition, vol. 127, pp. 1–15, 2025. @article{Gutzeit2025,Experiencing a sense of agency (SoA), the feeling of being in control over one's actions and their outcomes, typically requires intentional and voluntary actions. Prior research has compared the association of voluntary versus completely involuntary actions with the SoA. Here, we leveraged unique characteristics of oculomotor actions to partially manipulate the degree of action voluntariness. Participants performed either highly automatized prosaccades or highly controlled (voluntary) anti-saccades, triggering a gaze-contingent visual action effect. We assessed explicit SoA ratings and temporal action and effect binding as an implicit SoA measure. Anti-saccades were associated with stronger action binding compared to prosaccades, demonstrating a robust association between higher action voluntariness and a stronger implicit sense of action agency. We conclude that our manipulation of action voluntariness may have impacted the implicit phenomenological feeling of bodily agency, but it did not affect the SoA over effect outcomes or explicit agency perception. |
Maha Habibi; Brian C. Coe; Donald C. Brien; Jeff Huang; Heidi C. Riek; Frank Bremmer; Lars Timmermann; Annette Janzen; Wolfgang H. Oertel; Douglas P. Munoz Saccade, pupil, and blink abnormalities in prodromal and manifest Journal Article In: Journal of Parkinson's Disease, pp. 1–11, 2025. @article{Habibi2025,Background: Saccade, pupil, and blink control are impaired in patients with α-synucleinopathies (αSYN): Parkinson's disease (PD) and multiple system atrophy (MSA). Isolated REM (rapid eye movement) Sleep Behavior Disorder (iRBD) is a prodromal stage of PD and MSA and a prime candidate for investigating early oculo-pupillo-motor abnormalities that may precede or predict conversion to clinically manifest αSYN. Objective: Determine whether saccade, pupil, and blink responses in iRBD are normal or similar to those identified in PD and MSA. Methods: Video-based eye-tracking was conducted with 68 patients with iRBD, 49 with PD, 17 with MSA, and 95 healthy controls (CTRL) performing an interleaved pro-/anti-saccade task that probed sensory, motor, and cognitive processes involved in eye movement control. Results: Horizontal saccade and blink behavior was intact in iRBD, but abnormal in PD and MSA. iRBD patients, however, demonstrated reduced pupil dilation size, which closely resembled the changes found in PD and MSA. In the iRBD group, the extent of these pupillary changes appeared to correlate with the degree of hyposmia and reduction in dopamine trans- porter imaging signal. Conclusions: Pupil abnormalities were present in iRBD, but blink and horizontal saccade responses were intact. Future longitudinal studies are required to determine which prodromal pupil abnormalities predict conversion from iRBD to PD or MSA and to identify the time window, in relation to conversion, when horizontal saccade responses become abnormal. |
Jessica Heeman; Brian J. White; Stefan Van der Stigchel; Jan Theeuwes; Laurent Itti; Douglas P. Munoz Saliency response in superior colliculus at the future saccade goal predicts fixation duration during free viewing of dynamic scenes Journal Article In: The Journal of Neuroscience, vol. 45, no. 3, pp. 1–10, 2025. @article{Heeman2025,Eye movements in daily life occur in rapid succession and often without a predefined goal. Using a free viewing task, we examined how fixation duration prior to a saccade correlates to visual saliency and neuronal activity in the superior colliculus (SC) at the saccade goal. Rhesus monkeys (three male) watched videos of natural, dynamic, scenes while eye movements were tracked and, simultaneously, neurons were recorded in the superficial and intermediate layers of the superior colliculus (SCs and SCi, respectively), a midbrain structure closely associated with gaze, attention, and saliency coding. Saccades that were directed into the neuron's receptive field (RF) were extrapolated from the data. To interpret the complex visual input, saliency at the RF location was computed during the pre-saccadic fixation period using a computational saliency model. We analyzed if visual saliency and neural activity at the saccade goal predicted pre-saccadic fixation duration. We report three major findings: (1) Saliency at the saccade goal inversely correlated with fixation duration, with motion and edge information being the strongest predictors. (2) SC visual saliency responses in both SCs and SCi were inversely related to fixation duration. (3) SCs neurons, and not SCi neurons, showed higher activation for two consecutive short fixations, suggestive of concurrent saccade processing during free viewing. These results reveal a close correspondence between visual saliency, SC processing, and the timing of saccade initiation during free viewing and are discussed in relation to their implication for understanding saccade initiation during real-world gaze behavior. |
Matthias P. Baumann; Anna F. Denninger; Ziad M. Hafed Perisaccadic perceptual mislocalization strength depends on the visual appearance of saccade targets Journal Article In: Journal of Neurophysiology, vol. 133, pp. 85–100, 2025. @article{Baumann2025,We normally perceive a stable visual environment despite eye movements. To achieve such stability, visual processing integrates information across a given saccade, and laboratory hallmarks of such integration are robustly observed by presenting brief perisaccadic visual probes. In one classic phenomenon, probe locations are grossly mislocalized. This mislocalization is believed to depend, at least in part, on corollary discharge associated with saccade-related neuronal movement commands. However, we recently found that superior colliculus motor bursts, a known source of corollary discharge, can be different for different image appearances of the saccade target. Therefore, here we investigated whether perisaccadic mislocalization also depends on saccade target appearance. We asked human participants to generate saccades to either low (0.5 cycles/°) or high (5 cycles/°) spatial frequency gratings. We always placed a high-contrast target spot at grating center, to ensure matched saccades across image types. We presented a single, brief perisaccadic probe, which was high in contrast to avoid saccadic suppression, and the subjects pointed (via mouse cursor) at the seen probe location. We observed stronger perisaccadic mislocalization for low-spatial frequency saccade targets and for upper visual field probe locations. This was despite matched saccade metrics and kinematics across conditions, and it was also despite matched probe visibility for the different saccade target images (low vs. high spatial frequency). Assuming that perisaccadic visual mislocalization depends on corollary discharge, our results suggest that such discharge might relay more than just spatial saccade vectors to the visual system; saccade target visual features can also be transmitted.NEW & NOTEWORTHY Brief visual probes are grossly mislocalized when presented in the temporal vicinity of saccades. Although the mechanisms of such mislocalization are still under investigation, one component of them could derive from corollary discharge signals associated with saccade movement commands. Here, we were motivated by the observation that superior colliculus movement bursts, one source of corollary discharge, vary with saccade target image appearance. If so, then perisaccadic mislocalization should also do so, which we confirmed. |
Sydney Doré; Jonathan Coutinho; Aarlenne Z. Khan; Philippe Lefèvre; Gunnar Blohm Latency and amplitude of catch-up saccades to accelerating targets Journal Article In: Journal of Neurophysiology, vol. 133, no. 1, pp. 3–13, 2025. @article{Dore2025,To track moving targets, humans move their eyes using both saccades and smooth pursuit. If pursuit eye movements fail to accurately track the moving target, catch-up saccades are initiated to rectify the tracking error. It is well known that retinal position and velocity errors determine saccade latency and amplitude, but the extent to which retinal acceleration error influences these aspects is not well quantified. To test this, 13 adult human participants performed an experiment where they pursued accelerating/decelerating targets. During the ongoing pursuit, we introduced a randomly sized target step to evoke a catch-up saccade and analyzed its latency and amplitude. We observed that retinal acceleration error (computed over a 200 ms range centered 100 ms before the saccade) was a statistically significant predictor of saccade amplitude and latency. A multiple linear regression supported our hypothesis that retinal acceleration errors influence saccade amplitude in addition to the influence of retinal position and velocity errors. We also found that saccade latencies were shorter when retinal acceleration error increased the tracking error and vice versa. In summary, our findings support a model in which retinal acceleration error is used to compute a predicted position error ̴100 ms into the future to trigger saccades and determine saccade amplitude. |
Elana J. Forbes; Jeggan Tiego; Joshua Langmead; Kathryn E. Unruh; Matthew W. Mosconi; Amy Finlay; Kathryn Kallady; Lydia Maclachlan; Mia Moses; Kai Cappel; Rachael Knott; Tracey Chau; Vishnu Priya Mohanakumar Sindhu; Alessio Bellato; Madeleine J. Groom; Rebecca Kerestes; Mark A. Bellgrove; Beth P. Johnson Oculomotor function in children and adolescents with autism, ADHD or co-occurring autism and ADHD Journal Article In: Journal of Autism and Developmental Disorders, pp. 1–17, 2025. @article{Forbes2025,Oculomotor characteristics, including accuracy, timing, and sensorimotor processing, are considered sensitive intermediate phenotypes for understanding the etiology of neurodevelopmental conditions, such as autism and ADHD. Oculomotor characteristics have predominantly been studied separately in autism and ADHD. Despite the high rates of co-occurrence between these conditions, only one study has investigated oculomotor processes among those with co-occurring autism + ADHD. Four hundred and five (n = 405; 226 males) Australian children and adolescents aged 4 to 18 years (M = 9.64 years; SD = 3.20 years) with ADHD (n = 64), autism (n = 66), autism + ADHD (n = 146), or neurotypical individuals (n = 129) were compared across four different oculomotor tasks: visually guided saccade, anti-saccade, sinusoidal pursuit and step-ramp pursuit. Confirmatory analyses were conducted using separate datasets acquired from the University of Nottingham UK (n = 17 autism |
Yao-Tung Lee; Ying-Hsuan Tai; Yi-Hsuan Chang; Cesar Barquero; Shu-Ping Chao; Chin-An Wang Disrupted microsaccade responses in late-life depression Journal Article In: Scientific Reports, vol. 15, no. 1, pp. 1–11, 2025. @article{Lee2025,Late-life depression (LLD) is a psychiatric disorder in older adults, characterized by high prevalence and significant mortality rates. Thus, it is imperative to develop objective and cost-effective methods for detecting LLD. Individuals with depression often exhibit disrupted levels of arousal, and microsaccades, as a type of fixational eye movement that can be measured non-invasively, are known to be modulated by arousal. This makes microsaccades a promising candidate as biomarkers for LLD. In this study, we used a high-resolution, video-based eye-tracker to examine microsaccade behavior in a visual fixation task between LLD patients and age-matched healthy controls (CTRL). Our goal was to determine whether microsaccade responses are disrupted in LLD compared to CTRL. LLD patients exhibited significantly higher microsaccade peak velocities and larger amplitudes compared to CTRL. Although microsaccade rates were lower in LLD than in CTRL, these differences were not statistically significant. Additionally, while both groups displayed microsaccadic inhibition and rebound in response to changes in background luminance, this modulation was significantly blunted in LLD patients, suggesting dysfunction in the neural circuits responsible for microsaccade generation. Together, these findings, for the first time, demonstrate significant alterations in microsaccade behavior in LLD patients compared to CTRL, highlighting the potential of these disrupted responses as behavioral biomarkers for identifying individuals at risk for LLD. |
Matthew Lehet; Beier Yao; Ivy F. Tso; Vaibhav A. Diwadkar; Jessica Fattal; Jacqueline Bao; Katharine N. Thakkar Altered effective connectivity within a thalamocortical corollary discharge network in individuals with schizophrenia Journal Article In: Schizophrenia Bulletin, pp. 1–14, 2025. @article{Lehet2025,Background and Hypothesis: Sequential saccade planning requires corollary discharge (CD) signals that provide information about the planned landing location of an eye movement. These CD signals may be altered among individuals with schizophrenia (SZ), providing a potential mechanism to explain passivity and anomalous self-experiences broadly. In healthy controls (HC), a key oculomotor CD network transmits CD signals from the thalamus to the frontal eye fields (FEF) and the intraparietal sulcus (IPS) and also remaps signals from FEF to IPS. Study Design: Here, we modeled fMRI data using dynamic causal modeling (DCM) to examine patient-control differences in effective connectivity evoked by a double-step (DS) task (30 SZ, 29 HC). The interrogated network was formed from a combination of (1) functionally identified FEF and IPS regions that robustly responded on DS trials and (2) anatomically identified thalamic regions involved in CD transmission. We also examined the relationship between clinical symptoms and effective connectivity parameters associated with task modulation of network pathways. Study Results: Network connectivity was indeed modulated by the DS task, which involves CD transmission. More importantly, we found reduced effective connectivity from thalamus to IPS in SZ, which was further correlated with passivity symptom severity. Conclusions: These results reaffirm the importance of IPS and thalamocortical connections in oculomotor CD signaling and provide mechanistic insights into CD alterations and consequently agency disturbances in schizophrenia. |
Jui‐Tai T. Chen; Yi Hsuan Chang; Cesar Barquero; Moeka Mong Jia Teo; Nai Wen Kan; Chin An Wang Microsaccade behavior associated with inhibitory control in athletes in the antisaccade task Journal Article In: Psychology of Sport and Exercise, vol. 78, pp. 1–13, 2025. @article{Chen2025a,The ability to achieve a state of readiness before upcoming tasks, known as a preparatory set, is critical for athletic performance. Here, we investigated these preparatory processes associated with inhibitory control using the anti-saccade paradigm, in which participants are instructed, prior to target appearance, either to automatically look at the target (pro-saccade) or to suppress this automatic response and intentionally look in the opposite direction (anti-saccade). We focused on microsaccadic eye movements that happen before saccade responses in either pro- or anti-saccade tasks, as these microsaccades reflect ongoing preparatory processes during saccade planning before execution. We hypothesized that athletes, compared to non-athletes, would demonstrate better preparation, given research generally indicating higher inhibitory control in athletes. Our findings showed that microsaccade rates decreased before target appearance, with lower rates observed during anti-saccade preparation compared to pro-saccade preparation. However, microsaccade rates and metrics did not differ significantly between athletes and non-athletes. Moreover, reduced microsaccade rates were associated with improved task performance in non-athletes, leading to higher accuracy and faster saccade reaction times (SRTs) in trials without microsaccades. For athletes, only SRTs were affected by microsaccade occurrence. Moreover, the modulation of microsaccadic inhibition on accuracy was more pronounced in non-athletes compared to athletes. In conclusion, while microsaccade responses were modulated by task preparation, differences between athletes and non-athletes were non-significant. These findings, for the first time, highlight the potential of using microsaccades as an online objective index to study preparatory sets in sports science research. |
Ignace T. C. Hooge; Roy S. Hessels; Diederick C. Niehorster; Richard Andersson; Marta K. Skrok; Robert Konklewski; Patrycjusz Stremplewski; Maciej Nowakowski; Szymon Tamborski; Anna Szkulmowska; Maciej Szkulmowski; Marcus Nyström Eye tracker calibration: How well can humans refixate a target? Journal Article In: Behavior Research Methods, vol. 57, no. 1, pp. 1–10, 2025. @article{Hooge2025,Irrespective of the precision, the inaccuracy of a pupil-based eye tracker is about 0.5∘. This paper delves into two factors that potentially increase the inaccuracy of the gaze signal, namely, 1) Pupil-size changes and the pupil-size artefact (PSA) and 2) the putative inability of experienced individuals to precisely refixate a visual target. Experiment 1 utilizes a traditional pupil-CR eye tracker, while Experiment 2 employs a retinal eye tracker, the FreezeEye tracker, eliminating the pupil-based estimation. Results reveal that the PSA significantly affects gaze accuracy, introducing up to 0.5∘ inaccuracies during calibration and validation. Corrections based on the relation between pupil size and apparent gaze shift substantially reduce inaccuracies, underscoring the PSA's influence on eye-tracking quality. Conversely, Experiment 2 demonstrates humans' precise refixation abilities, suggesting that the accuracy of the gaze signal is not limited by human refixation inconsistencies. |
Juliano Setsuo Violin Kanamota; Gerson Yukio Tomanari; William J. McIlvane Tracking eye fixations during stimulus generalization tests Journal Article In: Psychological Record, pp. 1–10, 2025. @article{Kanamota2025,In the analysis of operant behavior, there is little empirical research on the relationship between observing responses and primary stimulus generalization. This work aimed to investigate eye fixations when S+ and S- dimensions were varied on generalization tests. Ten university students participated. Their training consisted of a MULT VI 1 s EXT schedule followed by MULT VI 2 s EXT schedule. Discriminative stimuli were three Gabor line tilts. S+ and S- had 45º and 135º slopes, respectively. After participants achieved discrimination indices of 75%, generalization tests in extinction began. There were two different conditions: (1) S+ was replaced by stimuli with angles of 15ο, 30ο, 45ο, 60ο, and 75ο (five participants). (2) S- was replaced by 105ο, 120ο, 135ο,, 150º, and 165º (five participants). In both training and tests, eye tracking equipment recorded observing responses defined as visual fixations. S+ variations yielded sharp observing response gradients. However, S- variations yielded flattened, bell-shaped, and U-shaped observing response gradients. These data contribute to the limited information on human observing during tests of primary stimulus generalization. The study provides a methodology for accomplishing a more complete characterization of behavioral processes that may be operative when normally capable adults are exposed to variations in S+ and S- on generalization tasks. |
Dmytro Katrychuk; Dillon J. Lohr; Oleg V. Komogortsev Oculomotor plan mathematical model in Kalman filter form with peak velocity-based neural pulse for continuous gaze prediction Journal Article In: IEEE Access, vol. 13, pp. 11544–11559, 2025. @article{Katrychuk2025,An oculomotor plant mathematical model (OPMM) employs physical and neurological characteristics of human visual system to define its dynamics. One of its most prominent applications in modern eye-tracking pipelines was hypothesized to be latency reduction via the means of eye movement prediction. However, this use case was only explored with OPMMs originally designed for saccade simulation. Such models typically relied on the neural pulse control being estimated from intended saccade amplitude - a property that becomes fully observed only after a saccade already ended, which greatly limits the model's prediction capabilities. We present the first OPMM designed with the prediction task in mind. We draw our inspiration from a "peak velocity - amplitude" main sequence relationship and propose to use saccade's peak velocity for neural pulse estimation. We additionally extend the prior work by evaluating the proposed model on the largest to date pool of 322 subjects against the naive zero displacement baseline and a long short-term memory (LSTM) neural network. |
Rita Cersosimo; Paul E. Engelhardt; Leigh Fernandez; Filippo Domaneschi Novel metaphor processing in dyslexia: A visual world eye-tracking study Journal Article In: Discourse Processes, pp. 1–21, 2025. @article{Cersosimo2025,Metaphor comprehension has been investigated in neurodevelopmental disorders, but studies devoted to adults with dyslexia are few and present inconsistent results. The present study sought to investigate how adults with dyslexia process novel metaphors. Individual differences in vocabulary, working memory, and Theory of Mind were also assessed. An online metaphor comprehension task based on the Visual World Paradigm was carried out with eye-tracking. Metaphors and corresponding literal sentences were aurally presented in isolation, and participants were asked to select a picture that best corresponded to the sentence they heard. Our results indicated that participants with dyslexia chose metaphor interpretations at a similar rate as did the control group. However, online processing data indicated generally slower response times, with a particular delay in processing metaphorical utterances. Eye movement analyses provided further insights into the underlying nature of the processing slowdowns, highlighting specific challenges encountered by individuals with dyslexia when interpreting figurative language. |
Jürgen Cholewa; Annika Kirschenkern; Frederike Steinke; Thomas Günther In: Journal of Speech, Language, and Hearing Research, pp. 1–19, 2025. @article{Cholewa2025,Purpose: Predictive language comprehension has become a major topic in psycholinguistic research. The study described in this article aims to investigate if German children with developmental language disorder (DLD) use grammatical gender agreement to predict the continuation of noun phrases in the same way as it has been observed for typically developing (TD) children. The study also seeks to differentiate between specific and general deficits in predictive processing by exploring the anticipatory use of semantic information. Additionally, the research examines whether the processing of gender and semantic information varies with the speed of stimulus presentation. Method: The study included 30 children with DLD (average age = 8.7 years) and 26 TD children (average age = 8.4 years) who participated in a visual-world eye- tracking study. Noun phrases, consisting of an article, an adjective, and a noun, were presented that matched with only one of two target pictures. The phrases contained a gender cue, a semantic cue, a combination of both, or none of these cues. The cues were provided by the article and/or adjective and could be used to identify the target picture before the noun itself was presented. Results: Both groups, TD children and those with DLD, utilized predictive processing strategies in response to gender agreement and semantic information when decoding noun phrases. However, children with DLD were only able to consider gender cues when noun phrases were presented at a slower speech rate, and even then, their predictive certainty remained below the typical level for their age. Conclusion: Based on these findings, the article discusses the potential relevance of the prediction framework for explaining comprehension deficits in chil- dren with DLD, as well as the clinical implications of the results. |
Claudio Terravecchia; Giovanni Mostile; Clara Grazia Chisari; Federico Contrafatto; Andrea Salerno; Giulia Donzuso; Calogero Edoardo Cicero; Giorgia Sciacca; Alessandra Nicoletti; Mario Zappia Different patterns of acute saccadic response to levodopa in de novo Parkinson's disease Journal Article In: Journal of Neurology, vol. 272, no. 1, pp. 1–10, 2025. @article{Terravecchia2025,Background: L-dopa (LD) effects on visually guided saccades (VGS) have been poorly investigated in de novo Parkinson's disease (PD) patients through a standardized acute challenge test. Objectives: To assess the acute saccadic effects of LD as well as possible different patterns of VGS response to LD in a consistent population of de novo PD. Methods: VGS were assessed among de novo PD at baseline and 2 h after the administration of LD/carbidopa 250/25 mg. Baseline instrumental assessments were compared with healthy controls (HCs). Results: Thirty-two de novo PD and 17 HCs were enrolled. PD patients showed lower upward velocities and amplitude than HCs, improving after LD administration. Two subgroups were identified among PD patients based on percent improvement or worsening of the most significant changing VGS parameter after LD administration: Group A (19 patients, showing improvement) and B (13 patients, showing worsening). Group A had at baseline reduced vertical, especially downward, velocities, gain and amplitude compared to Group B, with a significant improvement after LD. Conversely, in Group B, an LD-induced worsening effect on both horizontal and vertical VGS parameters was found. Comparing the two identified groups based on clinical–demographic characteristics, higher prevalence of female sex was found in Group B. Conclusions: De novo PD patients presented prominent vertical VGS impairment which improved acutely after LD administration. Different patterns of acute saccadic responses to LD were also shown, suggesting a possible role of VGS in PD phenotyping. |
Tommaso Tosato; Guillaume Dumas; Gustavo Rohenkohl; Pascal Fries Performance modulations phase-locked to action depend on internal state Journal Article In: iScience, vol. 28, no. 1, pp. 1–13, 2025. @article{Tosato2025,Previous studies have shown that perceptual performance can be modulated at specific frequencies phase-locked to self-paced motor actions, but findings have been inconsistent. To investigate this effect at the population level, we tested 50 participants who performed a self-paced button press followed by a threshold-level detection task, using both fixed- and random-effects analyses. Contrary to expectations, the aggregated data showed no significant action-related modulation. However, when accounting for internal states, we found that trials during periods of low performance or following a missed detection exhibited significant modulation at approximately 17 Hz. Additionally, participants with no false alarms showed similar modulation. These effects were significant in random effects tests, suggesting that they generalize to the population. Our findings indicate that action-related perceptual modulations are not always detectable but may emerge under specific internal conditions, such as lower attentional engagement or higher decision criteria, particularly in the beta-frequency range. |
Martin R. Vasilev; Zeynep Ozkan; Julie A. Kirkby; Antje Nuthmann; Fabrice B. R. Parmentier Unexpected sounds induce a rapid inhibition of eye-movement responses Journal Article In: Psychophysiology, vol. 62, pp. 1–19, 2025. @article{Vasilev2025,Abstract Unexpected sounds have been shown to trigger a global and transient inhibition of motor responses. Recent evidence suggests that eye movements may also be inhibited in a similar way, but it is not clear how quickly unexpected sounds can affect eye-movement responses. Additionally, little is known about whether they affect only voluntary saccades or also reflexive saccades. In this study, participants performed a pro-saccade and an anti- saccade task while the timing of sounds relative to stimulus onset was manipulated. Pro-saccades are generally reflexive and stimulus-driven, whereas anti- saccades require the generation of a voluntary saccade in the opposite direction of a peripheral stimulus. Unexpected novel sounds inhibited the execution of both pro- and anti-saccades compared to standard sounds, but the inhibition was stronger for anti-saccades. Novel sounds affected response latencies as early as 150 ms before the peripheral cue to make a saccade, all the way to 25 ms after the cue to make a saccade. Interestingly, unexpected sounds also reduced anti-saccade task errors, indicating that they aided inhibitory control. Overall, these results suggest that unexpected sounds yield a global and rapid inhibition of eye-movement responses. This inhibition also helps suppress reflexive eye-movement responses in favor of more voluntarily generated |
Rongwei Wang; Jianrong Jia Aperiodic pupil fluctuations at rest predict orienting of visual attention Journal Article In: Psychophysiology, vol. 62, no. 1, pp. 1–10, 2025. @article{Wang2025,The aperiodic exponent of the power spectrum of signals in several neuroimaging modalities has been found to be related to the excitation/inhibition balance of the neural system. Leveraging the rich temporal dynamics of resting-state pupil fluctuations, the present study investigated the association between the aperiodic exponent of pupil fluctuations and the neural excitation/inhibition balance in attentional processing. In separate phases, we recorded participants' pupil size during resting state and assessed their attentional orienting using the Posner cueing tasks with different cue validities (i.e., 100% and 50%). We found significant correlations between the aperiodic exponent of resting pupil fluctuations and both the microsaccadic and behavioral cueing effects. Critically, this relationship was particularly evident in the 50% cue-validity condition rather than in the 100% cue-validity condition. The microsaccadic responses mediated the association between the aperiodic exponent and the behavioral response. Further analysis showed that the aperiodic exponent of pupil fluctuations predicted the self-rated hyperactivity/impulsivity trait across individuals, suggesting its potential as a marker of attentional deficits. These findings highlight the rich information contained in pupil fluctuations and provide a new approach to assessing the neural excitation/inhibition balance in attentional processing. |
Vanessa Carneiro Morita; David Souto; Guillaume S. Masson; Anna Montagnini Anticipatory smooth eye movements scale with the probability of visual motion: Role of target speed and acceleration Journal Article In: Journal of Vision, vol. 25, no. 1, pp. 1–22, 2025. @article{Morita2025,Sensory-motor systems are able to extract statistical regularities in dynamic environments, allowing them to generate quicker responses and anticipatory behavior oriented towards expected events. Anticipatory smooth eye movements (aSEM) have been observed in primates when the temporal and kinematic properties of a forthcoming visual moving target are fully or partially predictable. However, the precise nature of the internal model of target kinematics which drives aSEM remains largely unknown, as well as its interaction with environmental predictability. In this study we investigated whether and how the probability of target speed or acceleration is taken into account for driving aSEM. We recorded eye movements in healthy human volunteers while they tracked a small visual target with either constant, accelerating or decelerating speed, keeping the direction fixed. Across experimental blocks, we manipulated the probability of the presented target motion properties, with either 100% probability of occurrence of one kinematic condition (fully-predictable sessions), or a mixture with different proportions of two conditions (mixture sessions). We show that aSEM are robustly modulated by the target kinematic properties. With constant-velocity targets, aSEM velocity scales linearly with target velocity across the blocked sessions, and it follows overall a probability-weighted average in the mixture sessions. Predictable target acceleration/deceleration does also have an influence on aSEM, but with more variability across participants. Finally, we show that the latency and eye acceleration at the initiation of visually-guided pursuit do also scale, overall, with the probability of target motion. This scaling is consistent with Bayesian integration of sensory and predictive information. ### Competing Interest Statement The authors have declared no competing interest. |
Sergio Navas‑León; Milagrosa Sánchez‑Martín; Ana Tajadura‑Jiménez; Lize De Coster; Mercedes Borda‑Mas; Luis Morales Exploring eye‑movement changes as digital biomarkers and endophenotypes in subclinical eating disorders: An eye tracking study Journal Article In: BMC Psychiatry, vol. 133, pp. 1–12, 2025. @article{Navas‑Leon2025,Objective: Previous research has indicated that patients with Anorexia Nervosa (AN) exhibit specific eye movement changes, identified through eye tracking sensor technology. These changes have been proposed as potential digital biomarkers and endophenotypes for early diagnosis and preventive clinical interventions. This study aims to explore whether these eye movement changes are also present in individuals with subclinical eating disorder (ED) symptomatology compared to control participants. Method: The study recruited participants using convenience sampling and employed the Eating Disorder Examination Questionnaire for initial screening. The sample was subsequently divided into two groups: individuals exhibiting subclinical ED symptomatology and control participants. Both groups performed various tasks, including a fixation task, prosaccade/antisaccade task, and memory‑guided task. Alongside these tasks, anxiety and premorbid intel‑ ligence were measured as potential confounding variables. The data were analyzed through means comparison and exploratory Pearson's correlations. Results No significant differences were found between the two groups in the three eye tracking tasks. Discussion The findings suggest that the observed changes in previous research might be more related to the clinical state of the illness rather than a putative trait. Implications for the applicability of eye movement changes as early biomarkers and endophenotypes for EDs in subclinical populations are discussed. Further research is needed to validate hese findings and understand their implications for preventive diagnostics. |
Elle Minh Ngoc Le Nguyen; Meaghan J. Clough; Joanne Fielding; Owen B. White A video-oculography study of fixation instability in myasthenia gravis Journal Article In: Frontiers in Neurology, vol. 16, pp. 1–9, 2025. @article{Nguyen2025,Introduction: Myasthenia gravis (MG) is an autoimmune disease that causes extraocular muscle weakness in up to 70–85% of patients, which can impact quality of life. Current diagnostic measures are not very sensitive for ocular MG. This study aimed to compare fixation instability (inability to maintain gaze on a target) in patients with MG with control participants using video-oculography. Methods: A prospective study of 20 age-and sex-matched MG and control participants was performed using a novel protocol with the EyeLink 1000 plus ©. Bivariate contour ellipse area (BCEA) analysis, number of fixations on a target, and percentage of dwell time of fixations in the target interest area (IA) were calculated. Inter-eye (right vs. left) comparisons were performed using paired t-tests, and inter-group (MG vs. control) comparisons were performed using independent samples t-tests. Results: There were no inter-eye differences in the BCEAs between control eyes and MG eyes. However, the BCEAs were larger in both the right (RE) and left (LE) eyes of MG patients in the right (RE p = 0.029, LE p = 0.033), left (RE p = 0.006, LE p = 0.004), upward (RE p = 0.009, LE p = 0.018), and downward (RE p = 0.006, LE p = 0.006) gaze holds of the controls. The total mean sum of gaze hold fixations in all directions was greater in MG patients than in control participants (354 ± 139 vs. 249 ± 135 |
Salar Nouri; Amirali Soltani Tehrani; Niloufar Faridani; Ramin Toosi; Jalaledin Noroozi; Mohammad Reza A. Dehaqani Microsaccade selectivity as discriminative feature for object decoding Journal Article In: iScience, vol. 28, no. 1, pp. 1–19, 2025. @article{Nouri2025,Microsaccades, a form of fixational eye movements, help maintain visual stability during stationary observations. This study examines the modulation of microsaccadic rates by various stimulus categories in monkeys and humans during a passive viewing task. Stimulus sets were grouped into four primary categories: human, animal, natural, and man-made. Distinct post-stimulus microsaccade patterns were identified across these categories, enabling successful decoding of the stimulus category with accuracy and recall of up to 85%. We observed that microsaccade rates are independent of pupil size changes. Neural data showed that category classification in the inferior temporal (IT) cortex peaks earlier than changes in microsaccade rates, suggesting feedback from the IT cortex influences eye movements after stimulus discrimination. These results contribute to neurobiological models, enhance human-machine interfaces, optimize experimental visual stimuli, and deepen understanding of microsaccades' role in object decoding. |
Ascensión Pagán; Federica Degno; Sara V. Milledge; Richard D. Kirkden; Sarah J. White; Simon P. Liversedge; Kevin B. Paterson Aging and word predictability during reading: Evidence from eye movements and fixation-related potentials Journal Article In: Attention, Perception, & Psychophysics, pp. 1–26, 2025. @article{Pagan2025,The use of context to facilitate the processing of words is recognized as a hallmark of skilled reading. This capability is also hypothesized to change with older age because of cognitive changes across the lifespan. However, research investigating this issue using eye movements or event-related potentials (ERPs) has produced conflicting findings. Specifically, whereas eye-movement studies report larger context effects for older than younger adults, ERP findings suggest that context effects are diminished or delayed for older readers. Crucially, these contrary findings may reflect methodological differences, including use of unnatural sentence displays in ERP research. To address these limitations, we used a coregistration technique to record eye movements (EMs) and fixation-related potentials (FRPs) simultaneously while 44 young adults (18–30 years) and 30 older adults (65+ years) read sentences containing a target word that was strongly or weakly predicted by prior context. Eye-movement analyses were conducted over all data (full EM dataset) and only data matching FRPs. FRPs were analysed to capture early and later components 70–900 ms following fixation-onset on target words. Both eye-movement datasets and early FRPs showed main effects of age group and context, while the full EM dataset and later FRPs revealed larger context effects for older adults. We argue that, by using coregistration methods to address limitations of earlier ERP research, our experiment provides compelling complementary evidence from eye movements and FRPs that older adults rely more on context to integrate words during reading. |
Jessica L. Parker; A. Caglar Tas The saccade target is prioritized for visual stability in naturalistic scenes Journal Article In: Vision Research, vol. 227, pp. 1–12, 2025. @article{Parker2025a,The present study investigated the mechanisms of visual stability using naturalistic scene images. In two experiments, we asked whether the visual system relies on spatial location of the saccade target, as previously found with simple dot stimuli, or relational positions of the objects in the scene during visual stability decisions. Using a modified version of the saccadic suppression of displacement task, we manipulated the information that is displaced in the scene as well as visual stability using intrasaccadic target blanking paradigm. There were four displacement conditions: saccade target, saccade source (Experiment 2 only), whole scene, and background. We also included a no-displacement control condition where everything remained stationary. Participants reported whether they detected any movement. The results showed that spatial displacements that occur in the saccade target object were more easily detected than any other displacements in the scene. Further, disrupting visual stability with blanking only improved displacement detection for the saccade target and saccade source objects, suggesting that saccade target and saccade source objects are both consulted in the establishment of visual stability, most likely due to both receiving selective attention before saccade execution. The present study is the first to show that the visual system uses similar visual stability mechanisms for simple dot stimuli and more naturalistic stimuli. |
Alessandro Piras The role of the peripheral target in stimulating eye movements Journal Article In: Psychology of Sport & Exercise, vol. 76, pp. 1–10, 2025. @article{Piras2025,The present study investigated the role of top-down and bottom-up processes during a deceptive sports strategy called “no-look passes” and how microsaccades and small saccades modulate these processes. The first experiment examined the role of expertise in modulating the shift of covert attention with the bottom-up procedure. Results showed more saccades of greater amplitude and faster peak velocity in amateur than in expert groups. In the second experiment, the shift of covert attention between top-down and bottom-up conditions was investigated in a group of expert basketball players. Analysis showed that athletes make more microsaccades during the bottom-up condition; meanwhile, during the top-down condition, they were pushed to make more small saccades to decide where to send the ball. The findings suggested that the top-down process stimulates the eyes to move more concerning the bottom-up condition. It could be explained by the fact that during the top-down condition, athletes do not have an "eyehold” that stimulates their attention. During the top-down condition, athletes had to shift their attention to both sides before making the pass, resulting in their eyes being more “hesitant” concerning the situation in which they are peripherally stimulated. |
Pierre Pouget; Pierre Daye; Martin Paré Cognitive and kinematic markers of ketamine effects in behaving non-human primates Journal Article In: European Journal of Pharmacology, vol. 987, pp. 1–7, 2025. @article{Pouget2025,Ketamine is widely used to probe cognitive functions relying on the properties of methyl-D-aspartate receptor (NMDAR) synaptic transmission. Numerous works have proved that cognitive performance and adjustments in the decision or perceptual domains are affected after ketamine injection in general circulation of primates. Here, we take advantage of that in the brain stem; horizontal saccade deceleration is controlled by glycine-NMDAR-gated current, while gamma-aminobutyric acid (GABA) current controls vertical deceleration to demonstrate that despite general circulation level manipulation of NMDAR synaptic transmission, the kinematic of the saccade appeared to be in the motor brainstem generator circuit differentially maintained. The results show that the deacceleration of the saccade elicited toward a horizontal target was substantially decreased, while the deacceleration of a vertical saccade remained largely unaffected. These results provide functional distinct markers for estimating cognitive and kinematic NMDAR-gated specificity acting in the pre-frontal cortex while maintaining specificity among the GABA circuit of drugs in general circulation. |
Ayushi Sangoi; Farzin Hajebrahimi; Suril Gohel; Mitchell Scheiman; Tara L. Alvarez Efferent compared to afferent neural substrates of the vergence eye movement system evoked via fMRI Journal Article In: Frontiers in Neuroscience, vol. 18, pp. 1–13, 2025. @article{Sangoi2025,Introduction: The vergence neural system was stimulated to dissect the afferent and efferent components of symmetrical vergence eye movement step responses. The hypothesis tested was whether the afferent regions of interest would differ from the efferent regions to serve as comparative data for future clinical patient population studies. Methods: Thirty binocularly normal participants participated in an oculomotor symmetrical vergence step block task within a functional MRI experiment compared to a similar sensory task where the participants did not elicit vergence eye movements. Results: For the oculomotor vergence task, functional activation was observed within the parietal eye field, supplemental eye field, frontal eye field, and cerebellar vermis, and activation in these regions was significantly diminished during the sensory task. Differences between the afferent sensory and efferent oculomotor experiments were also observed within the visual cortex. Discussion: Differences between the vergence oculomotor and sensory tasks provide a protocol to delineate the afferent and efferent portion of the vergence neural circuit. Implications with clinical populations and future therapeutic intervention studies are discussed. |
Marie Schroth; Wim Fias; Muhammet Ikbal Sahan Eye movements follow the dynamic shifts of attention through serial order in verbal working memory Journal Article In: Scientific Reports, vol. 15, no. 1, pp. 1–11, 2025. @article{Schroth2025,How are arbitrary sequences of verbal information retained and manipulated in working memory? Increasing evidence suggests that serial order in verbal WM is spatially coded and that spatial attention is involved in access and retrieval. Based on the idea that brain areas controlling spatial attention are also involved in oculomotor control, we used eye tracking to reveal how the spatial structure of serial order information is accessed in verbal working memory. In two experiments, participants memorized a sequence of auditory words in the correct order. While their eye movements were being measured, they named the memorized items in a self-determined order in Experiment 1 and in a cued order in Experiment 2. We tested the hypothesis that serial order in verbal working memory interacts with the spatial attention system whereby gaze patterns in visual space closely follow attentional shifts in the internal space of working memory. In both experiments, we found that the gaze shifts in visual space correlated with the spatial shifts of attention along the left-to-right one-dimensional mapping of serial order positions in verbal WM. These findings suggest that spatial attention is employed for dynamically searching through verbal WM and that eye movements reflect the spontaneous association of order and space even in the absence of visuospatial input. |
Yao Yan; Yilin Wu; Hoi Ming Ken Yip Nicholas; Nicholas Seow Chiang Price Metrics of two-dimensional smooth pursuit are diverse across participants and stable across days Journal Article In: Journal of Vision, vol. 25, no. 2, pp. 1–18, 2025. @article{Yan2025b,Smooth pursuit eye movements are used to volitionally track moving objects, keeping their image near the fovea. Pursuit gain, the ratio of eye to stimulus speed, is used to quantify tracking accuracy and is usually close to 1 for healthy observers. Although previous studies have shown directional asymmetries such as horizontal gain exceeding vertical gain, the temporal stability of these biases and the correlation between oculomotor metrics for tracking in different directions and speeds have not been investigated. Here, in testing sessions 4 to 10 days apart, 45 human observers tracked targets moving along two-dimensional trajectories. Horizontal, vertical, and radial pursuit gain had high test–retest reliability (mean intraclass correlation 0.84). The frequency of all saccades and anticipatory saccades during pursuit also had high test–retest reliability (intraclass correlation coefficients = 0.66 and 0.73, respectively). In addition, gain metrics showed strong intermetric correlation, and saccade metrics separately showed strong intercorrelation; however, gain and saccade metrics showed only weak intercorrelation. These correlations are likely to originate from a mixture of sensory, motor, and integrative mechanisms. The test–retest reliability of multiple distinct pursuit metrics represents a “pursuit identity” for individuals, but we argue against this ultimately contributing to an oculomotor biomarker. |
Liu Yang; Wenmao Zhang; Peitao Li; Hongjie Tang; Shuying Chen; Xinhong Jin The aiming advantages in experienced first-person shooter gamers: Evidence from eye movement patterns Journal Article In: Computers in Human Behavior, vol. 165, pp. 1–12, 2025. @article{Yang2025,The esports industry is expanding rapidly, with First-Person Shooter (FPS) games gaining unprecedented popularity, attracting millions of players and viewers worldwide. Proficiency in aiming is crucial in FPS games, serving as a critical factor for performance and victory. The present study explores the aiming advantages of experienced FPS players by analyzing their eye movement patterns under varying spatial and temporal conditions. Utilizing eye-tracking technology, data were collected from 63 participants, including 28 experienced FPS players and 35 non-FPS players. Task performance and eye movement indices such as accuracy, execution time, fixation count, and saccade count were analyzed. Results indicated that experienced FPS players exhibit faster execution times and more efficient eye movement patterns. Specifically, they more frequently exhibited the 0-fixation-1-saccade pattern, characterized by a single saccade without fixation, while showing fewer patterns requiring multiple corrective adjustments. This enhanced efficiency in visual search and eye-hand coordination likely contributes to their superior performance. Moreover, the study found that target distance and appearance latency significantly affect task performance and eye movement behavior. Greater distances and higher temporal uncertainty negatively impact performance, while spatiotemporal interactions are most influential near the fovea. These findings highlight the critical role of efficient eye movement patterns in enhancing aiming performance and suggest that FPS players could benefit from targeted eye-hand coordination training. |
Yuan Zhang; Giulia Agosti; Shuchen Guan; Doris I. Braun; Karl R. Gegenfurtner Dynamics of S-cone contributions to the initiation of saccadic and smooth pursuit eye movements Journal Article In: Journal of the Optical Society of America A, vol. 42, no. 5, pp. 256–265, 2025. @article{Zhang2025c,We investigated the interplaybetween luminance and heterochromatic brightness in guidingoculomotor behavior, particularly in saccades and smooth pursuit eye movements. We were particularly interested in testing whether mechanisms for eye target selection incorporate contributions from S-cones. Luminance, typically measured using the CIE's luminous efficiency function V(λ), has limitations in representing the perceived brightness of hetero- chromatic stimuli, especiallywith bluish and yellowish lights. S-cones do not contribute significantly to luminance but do influence brightness perception. To examine the S-cone contributions to oculomotor behavior, we mea- sured the target choices ofsaccades and smooth pursuit between equi-luminant bluish and yellowish stimuli, with paradigms producing a wide range of latencies. Our results show that at shorter latencies, luminance primarily drives both eye movements, with equi-luminant bluish and yellowish stimuli being chosen equally often.However, as latency increases, participants tend to choose bluish stimuli more frequently, suggesting that heterochromatic brightness plays a major role in longer-latency eye movements. This indicates that S-cone input may influence target selection as latency increases, highlighting a dynamic interaction between luminance and brightness in oculomotor decisions.We were particularly interested in investigating whether the mechanism responsible for eye movement target selection incorporates S-cone activity. |
2024 |
Mirjam C. M. Wever; Geert-Jan Will; Lisanne A. E. M. Houtum; Loes H. C. Janssen; Wilma G. M. Wentholt; Iris M. Spruit; Marieke S. Tollenaar; Bernet M. Elzinga Neural and affective responses to prolonged eye contact with parents in depressed and nondepressed adolescents Journal Article In: Cognitive, Affective, & Behavioral Neuroscience, vol. 24, no. 3, pp. 567–581, 2024. @article{Wever2024,Eye contact improves mood, facilitates connectedness, and is assumed to strengthen the parent–child bond. Adolescent depression is linked to difficulties in social interactions, the parent–child bond included. Our goal was to elucidate adolescents' affective and neural responses to prolonged eye contact with one's parent in nondepressed adolescents (HC) and how these responses are affected in depressed adolescents. While in the scanner, 59 nondepressed and 19 depressed adolescents were asked to make eye contact with their parent, an unfamiliar peer, an unfamiliar adult, and themselves by using videos of prolonged direct and averted gaze, as an approximation of eye contact. After each trial, adolescents reported on their mood and feelings of connectedness, and eye movements and BOLD-responses were assessed. In HCs, eye contact boosted mood and feelings of connectedness and increased activity in inferior frontal gyrus (IFG), temporal pole, and superior frontal gyrus. Unlike HCs, eye contact did not boost the mood of depressed adolescents. While HCs reported increased mood and feelings of connectedness to the sight of their parent versus others, depressed adolescents did not. Depressed adolescents exhibited blunted overall IFG activity. These findings show that adolescents are particularly sensitive to eye contact and respond strongly to the sight of their parents. This sensitivity seems to be blunted in depressed adolescents. For clinical purposes, it is important to gain a better understanding of how the responsivity to eye contact in general and with their parents in particular, can be restored in adolescents with depression. |
Raymond Ka Wong; Janahan Selvanayagam; Kevin Johnston; Stefan Everling Functional specialization and distributed processing across marmoset lateral prefrontal subregions Journal Article In: Cerebral Cortex, vol. 34, no. 10, pp. 1–15, 2024. @article{Wong2024,A prominent aspect of primate lateral prefrontal cortex organization is its division into several cytoarchitecturally distinct subregions. Neurophysiological investigations in macaques have provided evidence for the functional specialization of these subregions, but an understanding of the relative representational topography of sensory, social, and cognitive processes within them remains elusive. One explanatory factor is that evidence for functional specialization has been compiled largely from a patchwork of findings across studies, in many animals, and with considerable variation in stimulus sets and tasks. Here, we addressed this by leveraging the common marmoset (Callithrix jacchus) to carry out large-scale neurophysiological mapping of the lateral prefrontal cortex using high-density microelectrode arrays, and a diverse suite of test stimuli including faces, marmoset calls, and spatial working memory task. Task-modulated units and units responsive to visual and auditory stimuli were distributed throughout the lateral prefrontal cortex, while those with saccade-related activity or face-selective responses were restricted to 8aV, 8aD, 10, 46 V, and 47. Neurons with contralateral visual receptive fields were limited to areas 8aV and 8aD. These data reveal a mixed pattern of functional specialization in the lateral prefrontal cortex, in which responses to some stimuli and tasks are distributed broadly across lateral prefrontal cortex subregions, while others are more limited in their representation. |
Jordana S. Wynn; Daniel L. Schacter Eye movements reinstate remembered locations during episodic simulation Journal Article In: Cognition, vol. 248, pp. 1–6, 2024. @article{Wynn2024,Imagining the future, like recalling the past, relies on the ability to retrieve and imagine a spatial context. Research suggests that eye movements support this process by reactivating spatial contextual details from memory, a process termed gaze reinstatement. While gaze reinstatement has been linked to successful memory retrieval, it remains unclear whether it supports the related process of future simulation. In the present study, we recorded both eye movements and audio while participants described familiar locations from memory and subsequently imagined future events occurring in those locations while either freely moving their eyes or maintaining central fixation. Restricting viewing during simulation significantly reduced self-reported vividness ratings, supporting a critical role for eye movements in simulation. When viewing was unrestricted, participants spontaneously reinstated gaze patterns specific to the simulated location, replicating findings of gaze reinstatement during memory retrieval. Finally, gaze-based location reinstatement was predictive of simulation success, indexed by the number of internal (episodic) details produced, with both measures peaking early and co-varying over time. Together, these findings suggest that the same oculomotor processes that support episodic memory retrieval – that is, gaze-based reinstatement of spatial context – also support episodic simulation. |
Lin Xia; Yanming Wang; Sha Luo; Yong Zhang; Bensheng Qiu; Xiaoxiao Wang; Lixia Feng Abnormal occipital and frontal activity during voluntary convergence in intermittent exotropia: A task-fMRI study Journal Article In: Heliyon, vol. 10, no. 5, pp. 1–7, 2024. @article{Xia2024,Intermittent exotropia (IXT) is characterized by intermittently outward deviation of the eye and involved with vergence dysfunction. This study aimed to investigate the brain areas related to voluntary convergence and cortical activation changes between IXT patients and normal subjects. A total of 21 subjects, including 11 IXT patients and 10 age- and sex-matched normal subjects, were recruited for this study. A voluntary convergence task was employed, with changes in brain function measured by functional magnetic resonance imaging (fMRI). Correlations between cortical activation and clinical measurements were conducted by Pearson's correlation analysis. fMRI results showed that during voluntary convergence, the medial frontal gyrus (MFG) and bilateral occipital cortex were activated in the normal group, whereas only activation of the occipital cortex in IXT patients. Compared with the normal, IXT patients showed hypo-activation of both the MFG and cuneus during the task. The activation of MFG was negatively correlated to the duration of IXT. This study demonstrates that both MFG and occipital cortex may participate in voluntary convergence in normal subjects, while IXT patients have an aberrant cortical function of the MFG and cuneus, and the duration of IXT likely influences the severity of MFG. These findings may provide valuable insights for understanding the relationship between convergence and IXT. |
Xinyi Xia; Qin Liu; Erik D. Reichle; Yanping Liu Saccadic targeting in the Landolt-C task: Implications for Chinese reading Journal Article In: Journal of Experimental Psychology: Learning, Memory, and Cognition, vol. 50, no. 11, pp. 1749–1771, 2024. @article{Xia2024a,Participants in an eye-movement experiment performed a modified version of the Landolt-C paradigm (Williams & Pollatsek, 2007) to determine if there are preferred viewing locations when they searched for target squares embedded in linear arrays of spatially contiguous clusters of squares (i.e., sequences of one to four squares having missing segments of variable size and orientation). The results of this experiment indicate that, although the peaks of the single- and first-of-multiple-fixation landing-site distributions were respectively located near the centers and beginnings of the clusters, thereby replicating previous patterns that have been interpreted as evidence for the default saccadic-targeting hypothesis, the same dissociation was evident on nonclusters (i.e., arbitrarily defined regions of analysis). Furthermore, properties of the clusters (e.g., character number and gap size) influenced fixation durations and forward saccade length, suggesting that ongoing stimulus processing affects decisions about when and where (i.e., how far) to move the eyes. Finally, results of simulations using simple oculomotor-based, default-targeting, and dynamic-adjustment models indicated that the latter performed better than the other two, suggesting that the dynamic-adjustment strategy likely reflects the basic perceptual and motor constraints shared by a variety of visual tasks, rather than being specific to Chinese reading. The theoretical implications of these results for existing and future accounts of eye-movement control are discussed. |
Beier Yao; Martin Rolfs; Rachael Slate; Dominic Roberts; Jessica Fattal; Eric D. Achtyes; Ivy F. Tso; Vaibhav A. Diwadkar; Deborah Kashy; Jacqueline Bao; Katharine N. Thakkar Abnormal oculomotor corollary discharge signaling as a trans-diagnostic mechanism of psychosis Journal Article In: Schizophrenia Bulletin, vol. 50, no. 3, pp. 631–641, 2024. @article{Yao2024b,Background and Hypothesis: Corollary discharge (CD) signals are “copies” of motor signals sent to sensory areas to predict the corresponding input. They are a posited mechanism enabling one to distinguish actions generated by oneself vs external forces. Consequently, altered CD is a hypothesized mechanism for agency disturbances in psychosis. Previous studies have shown a decreased influence of CD signals on visual perception in individuals with schizophrenia—particularly in xthose with more severe positive symptoms. We therefore hypothesized that altered CD may beatrans-diagnosticmechanismof psychosis. StudyDesign: We examined oculomotor CD (using the blanking task) in 49 participants with schizophrenia or schizoaffective disorder (SZ), 36 bipolar participants with psychosis (BPP), and 40 healthy controls (HC). Participants made a saccade to a visual target. Upon saccade initiation, the target disappeared and reappeared at a horizontally displaced position. Participants indicated the direction of displacement. With intact CD, participants can make accurate perceptual judgements. Otherwise, participants may use saccade landing site as a proxy of pre-saccadic target to inform perception. Thus, multi-level modeling was used to examine the influence of target displacement and saccade landing site on displacement judgements. Study Results: SZ and BPP were equally less sensitive to target displacement than HC. Moreover, regardless of diagnosis, SZ and BPP with more severe positive symptoms were more likely to rely on saccade landing site. Conclusions: These results suggest that altered CD may be a trans-diagnostic mechanism of psychosis. |
Sophie C. Yue; Gokce B. Cakir; Aasef Shaikh; Fatema F. Ghasia Assessing inter-ocular fixational eye movements throughout the lifespan Journal Article In: Experimental Brain Research, vol. 24, pp. 2749–2763, 2024. @article{Yue2024,This study aims to assess fixational eye movements (FEMs) obtained under binocular and monocular viewing in normal individuals across different age groups. We recruited 68 healthy participants divided into Group 1 (children, 3–9 years |
Mengdie Zhai; Hongxiao Wu; Yajie Wang; Yu Liao; Wenfeng Feng Sound reduces saccadic chronostasis illusion Journal Article In: Vision Research, vol. 215, pp. 1–11, 2024. @article{Zhai2024,The saccadic chronostasis illusion refers to the duration overestimation of the first visual stimulation after saccadic eye movement, which is also known as “stopped clock illusion.” The present study investigated whether saccadic chronostasis would be observed in the auditory modality and whether the saccade-induced time dilation in the visual modality would be reduced by a synchronously presented sound. In each trial, a unisensory visual stimulus, unisensory sound, or bimodal audio-visual stimulus with a duration of 200–800 ms (probe stimulus) was presented at the saccade target location and temporally around the offset of the saccade, followed by a unisensory visual or auditory standard stimulus for a fixed 500 ms. Participants were required to identify which of the two stimuli (probe or standard) presented in the target modality (visual or auditory) was perceived as longer. The results showed that no saccadic chronostasis was observed in the auditory modality, regardless of whether the sound was presented alone or synchronously accompanied by a visual stimulus. Interestingly, the magnitude of the saccadic chronostasis illusion was reduced by the synchronously presented sound. Moreover, the combined effect of the saccade and sound on visual time perception fits well with the standard scalar model, and the weight of the cross-modal effect was higher than that of saccadic visual time dilation. These results suggest that sound dominates vision in time processing during saccades and linearly modulates saccadic chronostasis, which follows the Scalar Expectancy Theory. |
Dan Zhang; Lihua Xu; Xu Liu; Huiru Cui; Yanyan Wei; Wensi Zheng; Yawen Hong; Zhenying Qian; Yegang Hu; Yingying Tang; Chunbo Li; Zhi Liu; Tao Chen; Haichun Liu; Tianhong Zhang; Jijun Wang Eye movement characteristics for predicting a transition to psychosis: Longitudinal changes and implications Journal Article In: Schizophrenia Bulletin, pp. 1–10, 2024. @article{Zhang2024,BACKGROUND AND HYPOTHESIS: Substantive inquiry into the predictive power of eye movement (EM) features for clinical high-risk (CHR) conversion and their longitudinal trajectories is currently sparse. This study aimed to investigate the efficiency of machine learning predictive models relying on EM indices and examine the longitudinal alterations of these indices across the temporal continuum. STUDY DESIGN: EM assessments (fixation stability, free-viewing, and smooth pursuit tasks) were performed on 140 CHR and 98 healthy control participants at baseline, followed by a 1-year longitudinal observational study. We adopted Cox regression analysis and constructed random forest prediction models. We also employed linear mixed-effects models (LMMs) to analyze longitudinal changes of indices while stratifying by group and time. STUDY RESULTS: Of the 123 CHR participants who underwent a 1-year clinical follow-up, 25 progressed to full-blown psychosis, while 98 remained non-converters. Compared with the non-converters, the converters exhibited prolonged fixation durations, decreased saccade amplitudes during the free-viewing task; larger saccades, and reduced velocity gain during the smooth pursuit task. Furthermore, based on 4 baseline EM measures, a random forest model classified converters and non-converters with an accuracy of 0.776 (95% CI: 0.633, 0.882). Finally, LMMs demonstrated no significant longitudinal alterations in the aforementioned indices among converters after 1 year. CONCLUSIONS: Aberrant EMs may precede psychosis onset and remain stable after 1 year, and applying eye-tracking technology combined with a modeling approach could potentially aid in predicting CHRs evolution into overt psychosis. |
Han Zhang; Tessa R. Abagis; Clara J. Steeby; John Jonides Lingering on distraction: Examining distractor rejection in adults with ADHD Journal Article In: Visual Cognition, pp. 1–15, 2024. @article{Zhang2024a,Effective visual search relies on reactively disengaging from distractors when the features of the distractors are unpredictable. Does this ability differ between adults with and without Attention-Deficit/Hyperactivity Disorder (ADHD)?. Participants (36 with ADHD, 46 non-ADHD) completed the additional-singleton task, in which they searched for a unique shape while a uniquely coloured distractor unpredictably appeared on half of the trials. The distractor delayed manual response times in both groups, with no significant group difference. Both groups also demonstrated similar oculomotor capture effects, as indicated by the landing position of initial fixations. However, when initial fixations did land on the distractor, participants with ADHD tended to “linger” on the distractor with additional fixations and longer duration before disengaging from it, compared to those without ADHD. These results suggest that ADHD is associated with deficits in reactively disengaging from distractions rather than deficits in avoiding being captured in the first place. |
Yuan Zhang; Matteo Valsecchi; Karl R. Gegenfurtner; Jing Chen The execution of saccadic eye movements suppresses visual processing of both color and luminance in the early visual cortex of humans Journal Article In: Journal of Neurophysiology, vol. 131, no. 6, pp. 1156–1167, 2024. @article{Zhang2024n,Our eyes execute rapid, directional movements known as saccades, occurring several times per second, to focus on objects of interest in our environment. During these movements, visual sensitivity is temporarily reduced. Despite numerous studies on this topic, the underlying mechanism remains elusive, including a lingering debate on whether saccadic suppression affects the parvocellular visual pathway. To address this issue, we conducted a study employing steady-state visual evoked potentials (SSVEPs) elicited by chromatic and luminance stimuli while observers performed saccadic eye movements. We also employed an innovative analysis pipeline to enhance the signal-to-noise ratio, yielding superior results compared to the previous method. Our findings revealed a clear suppression effect on SSVEP signals during saccades compared to fixation periods. Notably, this suppression effect was comparable for both chromatic and luminance stimuli. We went further to measure the suppression effect across various contrast levels, which enabled us to model SSVEP responses with contrast response functions. The results suggest that saccades primarily reduce response gain without significantly affecting contrast gain and that this reduction applies uniformly to both chromatic and luminance pathways. In summary, our study provides robust evidence that saccades similarly suppress visual processing in both the parvocellular and magnocellular pathways within the human early visual cortex, as indicated by SSVEP responses. The observation that saccadic eye movements impact response gain rather than contrast gain implies that they influence visual processing through a multiplicative mechanism. |
Sijia Zhao; Claudia Contadini-Wright; Maria Chait Cross-modal interactions between auditory attention and oculomotor control Journal Article In: The Journal of Neuroscience, vol. 44, no. 11, pp. 1–10, 2024. @article{Zhao2024c,Microsaccades are small, involuntary eye movements that occur during fixation. Their role is debated with recent hypotheses proposing a contribution to automatic scene sampling. Microsaccadic inhibition (MSI) refers to the abrupt suppression of microsaccades, typically evoked within 0.1 s after new stimulus onset. The functional significance and neural underpinnings of MSI are subjects of ongoing research. It has been suggested that MSI is a component of the brain's attentional re-orienting network which facilitates the allocation of attention to new environmental occurrences by reducing disruptions or shifts in gaze that could interfere with processing. The extent to which MSI is reflexive or influenced by top–down mechanisms remains debated. We developed a task that examines the impact of auditory top–down attention on MSI, allowing us to disentangle ocular dynamics from visual sensory processing. Participants (N = 24 and 27; both sexes) listened to two simultaneous streams of tones and were instructed to attend to one stream while detecting specific task “targets.” We quantified MSI in response to occasional task-irrelevant events presented in both the attended and unattended streams (frequency steps in Experiment 1, omissions in Experiment 2). The results show that initial stages of MSI are not affected by auditory attention. However, later stages (∼0.25 s postevent onset), affecting the extent and duration of the inhibition, are enhanced for sounds in the attended stream compared to the unattended stream. These findings provide converging evidence for the reflexive nature of early MSI stages and robustly demonstrate the involvement of auditory attention in modulating the later stages. |
Hong Zhou; Luhua Wei; Yanyan Jiang; Xia Wang; Yunchuang Sun; Fan Li; Jing Chen; Wei Sun; Lin Zhang; Guiping Zhao; Zhaoxia Wang Abnormal ocular movement in the early stage of multiple-system atrophy with predominant parkinsonism distinct from Parkinson's disease Journal Article In: Journal of Clinical Neurology, vol. 20, no. 1, pp. 37–45, 2024. @article{Zhou2024c,Background and Purpose The eye-movement examination can be applied as a noninvasive method to identify multiple-system atrophy (MSA). Few studies have investigated eye movements during the early stage of MSA with predominant parkinsonism (MSA-P). We aimed to determine the characteristic oculomotor changes in the early stage of MSA-P. Methods We retrospectively selected 17 patients with MSA-P and 40 with Parkinson's disease (PD) with disease durations of less than 2 years, and 40 age-matched healthy controls (HCs). Oculomotor performance in the horizontal direction was measured in detail using videonystagmography. Results We found that the proportions of patients with MSA-P and PD exhibiting abnormal eye movements were 82.4% and 77.5%, respectively, which were significantly higher than that in the HCs (47.5%, p<0.05). Compared with HCs, patients with MSA-P presented significantly higher abnormal proportions of fixation and gaze-holding (17.6% vs. 0%), without-fixation (47.1% vs. 0%), prolonged latency in reflexive saccades (29.4% vs. 5.0%), memory-guided saccades (93.3% vs. 10.0%), and catch-up saccades in smooth-pursuit movement (SPM, 41.2% vs. 0) (all p<0.05). Compared with those with PD, patients with MSA-P presented a signifi- cantly higher proportion of catch-up saccades in SPM (41.2% vs. 2.5%, p<0.001). Conclusions MSA-P presented the characteristic of catch-up saccades in SPM in the early stage, which may provide some value in differentiating MSA-P from PD. |
Jiahui Zhu; Jinhao Li; Li Zhou; Lingzi Xu; Chengcheng Pu; Bingjie Huang; Qi Zhou; Yunhan Lin; Yajing Tang; Liu Yang; Chuan Shi Eye movements as predictor of cognitive improvement after cognitive remediation therapy in patients with schizophrenia Journal Article In: Frontiers in Psychiatry, vol. 15, pp. 1–15, 2024. @article{Zhu2024b,Aim: Baseline cognitive functions of patients predicted the efficacy of cognitive remediation therapy (CRT), but results are mixed. Eye movement is a more objective and advanced assessment of cognitive functions than neuropsychological testing. We aimed to investigate the applicability of eye movements in predicting cognitive improvement after patients with schizophrenia were treated with CRT. Methods: We recruited 79 patients with schizophrenia to complete 8 weeks of CRT and assessed their cognitive improvement outcomes. Eye movements were assessed by prosaccades, antisaccades, and free-viewing tasks at baseline, and neuropsychological tests in four cognitive domains were assessed before and after treatment to calculate treatment outcomes. Predictors of demographic information, clinical characteristics, and eye movement measures at baseline on cognitive improvement outcomes were analyzed using logistic regression analysis. We further compared the predictive performance between eye movement measurements and neuropsychological test regarding the effect of CRT on cognitive improvement, and explored factors that could be affect the treatment outcomes in different cognitive domains. Results: As operationally defined, 33 patients showed improved in cognition (improved group) and 46 patients did not (non-improved group) after CRT. Patients with schizophrenia being employed, lower directional error rate in antisaccade task, and lower the gap effect (i.e., the difference in saccadic latency between the gap condition and overlap condition) in prosaccade task at baseline predicted cognitive improvement in CRT. However, performance in the free-viewing task not associated with cognitive improvement in patients in CRT. Our results show that eye-movement prediction model predicted the effect of CRT on cognitive improvement in patients with schizophrenia better than neuropsychological prediction model in CRT. In addition, baseline eye-movements, cognitive reserve, antipsychotic medication dose, anticholinergic cognitive burden change, and number of training sessions were associated with improvements in four cognitive domains. Conclusion: Eye movements as a non-invasiveness, objective, and sensitive method of evaluating cognitive function, and combined saccadic measurements in pro- and anti-saccades tasks could be more beneficial than free-viewing task in predicting the effect of CRT on cognitive improvement in patients with schizophrenia. |
Jiahui Zhu; Li Zhou; Yuanyuan Zhou; Yunhan Lin; Yumei Cai; Jiayuan Wu; Chuan Shi Diagnosis of schizophrenia by integrated saccade scores and associations with psychiatric symptoms, and functioning Journal Article In: Medicine, vol. 103, no. 41, pp. 1–9, 2024. @article{Zhu2024c,Eye movement as a neurobiological biomarker of schizophrenia. We aim to estimate diagnostic accuracy of integrated pro/antisaccade eye movement measurements to discriminate between healthy individuals and schizophrenic patients. We compared the eye movement performance of 85 healthy individuals and 116 schizophrenia-stable patients during prosaccade and antisaccade tasks. The difference eye movement measurements were accumulated by stepwise discriminant analysis to produce an integrated score. Finally, the diagnostic value of the integrated score was calculated by the receiver operating characteristic (ROC) area under the curve (AUC), and the best sensitivity and specificity were calculated based on the given cutoff values. Using discriminant analysis, an integrated score included the residual gain and latency (step) during the prosaccade test, the error rate, and the corrected error rate during the antisaccade test. We found that the integrated score could well classify schizophrenia patients and healthy individuals with an accuracy of 80.6%. In the ROC, Youden's index was 0.634 (sensitivity = 81.0% |
Zikang Zhu; Byounghoon Kim; Raymond Doudlah; Ting Yu Chang; Ari Rosenberg Differential clustering of visual and choice- and saccade-related activity in macaque V3A and CIP Journal Article In: Journal of Neurophysiology, vol. 131, no. 4, pp. 709–722, 2024. @article{Zhu2024f,Neurons in sensory and motor cortices tend to aggregate in clusters with similar functional properties. Within the primate dorsal ("where") pathway, an important interface between three-dimensional (3-D) visual processing and motor-related functions consists of two hierarchically organized areas: V3A and the caudal intraparietal (CIP) area. In these areas, 3-D visual information, choice-related activity, and saccade-related activity converge, often at the single-neuron level. Characterizing the clustering of functional properties in areas with mixed selectivity, such as these, may help reveal organizational principles that support sensorimotor transformations. Here we quantified the clustering of visual feature selectivity, choice-related activity, and saccaderelated activity by performing correlational and parametric comparisons of the responses of well-isolated, simultaneously recorded neurons in macaque monkeys. Each functional domain showed statistically significant clustering in both areas. However, there were also domain-specific differences in the strength of clustering across the areas. Visual feature selectivity and saccade-related activity were more strongly clustered in V3A than in CIP. In contrast, choice-related activity was more strongly clustered in CIP than in V3A. These differences in clustering may reflect the areas' roles in sensorimotor processing. Stronger clustering of visual and saccade-related activity in V3A may reflect a greater role in within-domain processing, as opposed to cross-domain synthesis. In contrast, stronger clustering of choice-related activity in CIP may reflect a greater role in synthesizing information across functional domains to bridge perception and action. |
Eckart Zimmermann Compression of time in double-step saccades Journal Article In: Journal of Neurophysiology, vol. 132, no. 1, pp. 61–67, 2024. @article{Zimmermann2024,Temporal intervals appear compressed at the time of saccades. Here, I asked if saccadic compression of time is related to motor planning or to saccade execution. To dissociate saccade motor planning from its execution, I used the double-step paradigm, in which subjects have to perform two horizontal saccades successively. At various times around the saccade sequence, I presented two large horizontal bars, which marked an interval lasting 100 ms. After 700 ms, a second temporal interval was presented, varying in duration across trials. Subjects were required to judge which interval appeared shorter. I found that during the first saccades in the double-step paradigm, temporal intervals were compressed. Maximum temporal compression coincided with saccade onset. Around the time of the second saccade, I found temporal compression as well, however, the time of maximum compression preceded saccade onset by about 70 ms. I compared the magnitude and time of temporal compression between double-step saccades and amplitude-matched single saccades, which I measured separately. Although I found no difference in time compression magnitude, the time when maximum compression occurred differed significantly. I conclude that the temporal shift of time compression in double-step saccades demonstrates the influence of saccade motor planning on time perception. NEW & NOTEWORTHY Visually defined temporal intervals appear compressed at the time of saccades. Here, I tested time perception during double-step saccades dissociating saccade planning from execution. Although around the time of the first saccade, peak compression was found at saccade onset, compression around the time of the second saccade peaked 70 ms before saccade onset. The results suggest that saccade motor planning influences time perception. |
Inbal Ziv; Inbar Avni; Ilan Dinstein; Gal Meiri; Yoram S. Bonneh Oculomotor randomness is higher in autistic children and increases with the severity of symptoms Journal Article In: Autism Research, vol. 17, no. 2, pp. 249–265, 2024. @article{Ziv2024,A variety of studies have suggested that at least some children with autism spectrum disorder (ASD) view the world differently. Differences in gaze patterns as measured by eye tracking have been demonstrated during visual exploration of images and natural viewing of movies with social content. Here we analyzed the temporal randomness of saccades and blinks during natural viewing of movies, inspired by a recent measure of “randomness” applied to micro-movements of the hand and head in ASD (Torres et al., 2013; Torres & Denisova, 2016). We analyzed a large eye-tracking dataset of 189 ASD and 41 typically developing (TD) children (1–11 years old) who watched three movie clips with social content, each repeated twice. We found that oculomotor measures of randomness, obtained from gamma parameters of inter-saccade intervals (ISI) and blink duration distributions, were significantly higher in the ASD group compared with the TD group and were correlated with the ADOS comparison score, reflecting increased “randomness” in more severe cases. Moreover, these measures of randomness decreased with age, as well as with higher cognitive scores in both groups and were consistent across repeated viewing of each movie clip. Highly “random” eye movements in ASD children could be associated with high “neural variability” or noise, poor sensory-motor control, or weak engagement with the movies. These findings could contribute to the future development of oculomotor biomarkers as part of an integrative diagnostic tool for ASD. |
Petr Adámek; Dominika Grygarová; Lucia Jajcay; Eduard Bakštein; Petra Fürstová; Veronika Juríčková; Juraj Jonáš; Veronika Langová; Iryna Neskoroďana; Ladislav Kesner; Jiří Horáček The gaze of schizophrenia patients captured by bottom-up saliency Journal Article In: Schizophrenia, vol. 10, no. 1, pp. 1–13, 2024. @article{Adamek2024,Schizophrenia (SCHZ) notably impacts various human perceptual modalities, including vision. Prior research has identified marked abnormalities in perceptual organization in SCHZ, predominantly attributed to deficits in bottom-up processing. Our study introduces a novel paradigm to differentiate the roles of top-down and bottom-up processes in visual perception in SCHZ. We analysed eye-tracking fixation ground truth maps from 28 SCHZ patients and 25 healthy controls (HC), comparing these with two mathematical models of visual saliency: one bottom-up, based on the physical attributes of images, and the other top-down, incorporating machine learning. While the bottom-up (GBVS) model revealed no significant overall differences between groups (beta = 0.01 |
Müge Akkoyun; Koray Koçoğlu; Hatice Eraslan Boz; Işıl Yağmur Tüfekci; Merve Ekin; Gülden Akdal Visual search for real-world scenes in patients with Alzheimer's disease and amnestic mild cognitive impairment Journal Article In: Brain and Behavior, vol. 14, no. 6, pp. 1–11, 2024. @article{Akkoyun2024,Background: Visual attention-related processes that underlie visual search behavior are impaired in both the early stages of Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI), which is considered a risk factor for AD. Although traditional computer-based array tasks have been used to investigate visual search, information on the visual search patterns of AD and MCI patients in real-world environments is limited. Aim: The objective of this study was to evaluate the differences in visual search behaviors among individuals with AD, aMCI, and healthy controls (HCs) in real-world scenes. Materials and Methods: A total of 92 participants were enrolled, including 28 with AD, 32 with aMCI, and 32 HCs. During the visual search task, participants were instructed to look at a single target object amid distractors, and their eye movements were recorded. Results: The results indicate that patients with AD made more fixations on distractors and fewer fixations on the target, compared to patients with aMCI and HC groups. Additionally, AD patients had longer fixation durations on distractors and spent less time looking at the target than both patients with aMCI and HCs. Discussion: These findings suggest that visual search behavior is impaired in patients with AD and can be distinguished from aMCI and healthy individuals. For future studies, it is important to longitudinally monitor visual search behavior in the progression from aMCI to AD. Conclusion: Our study holds significance in elucidating the interplay between impairments in attention, visual processes, and other underlying cognitive processes, which contribute to the functional decline observed in individuals with AD and aMCI. |
Evin Aktar; Marianna Venetikidi; Bram Bockstaele; Danielle Giessen; Koraly Pérez-Edgar Pupillary responses to dynamic negative versus positive facial expressions of emotion in children and parents: Links to depression and anxiety Journal Article In: Developmental Psychobiology, vol. 66, no. 6, pp. 1–15, 2024. @article{Aktar2024,Witnessing emotional expressions in others triggers physiological arousal in humans. The current study focused on pupil responses to emotional expressions in a community sample as a physiological index of arousal and attention. We explored the associations between parents' and offspring's responses to dynamic facial expressions of emotion, as well as the links between pupil responses and anxiety/depression. Children (N = 90 |
Douglas P. Munoz; Brian J. White; Donald C. Brien; Kajaal Parbhoo; Carmen Yea; E. Ann Yeh Saccade and pupil changes in children recovering from opsoclonus‐myoclonus ataxia syndrome reveal midbrain alterations in oculomotor circuits Journal Article In: Annals of the Child Neurology Society, vol. 2, no. 3, pp. 212–224, 2024. @article{Munoz2024,Objective: This study measured eye movements in children with a history of opsoclonus‐myoclonus ataxia syndrome in order to identify abnormalities in saccade and pupil behavior that map onto specific alterations in brainstem pathways. Methods: We used video‐based eye tracking while participants freely viewed 10 min of short (2–4 s) video clips without instructions. Clip transitions represented a large visual perturbation and we quantified multiple characteristics of saccade and pupil responses following these transitions in 13 children recovering from opsoclonus‐myoclonus and 13 healthy, age‐matched control participants. Results: The frequency of saccades and distribution of fixation durations differed between the groups. Following the clip transitions, children recovering from opsoclonus‐myoclonus ataxia syndrome exhibited longer time to initiate saccades, leading to a delay in harvesting visual information. Clip transitions to lighter clips produced similar pupil constriction responses in the two groups. However, clip transitions to darker clips produced dilation responses that were initiated earlier and of greater magnitude in opsoclonus‐myoclonus ataxia syndrome, suggesting removal or suppression of a signal that delays dilation. Interpretation: Children with a history of opsoclonus‐myoclonus ataxia syndrome demonstrated key abnormalities in saccade and pupil metrics. We propose a novel hypothesis in which dysfunction in the pathway from the superior colliculus to the mesencephalic and pontine reticular formation that houses the saccade and pupil premotor circuits could produce these results. |
Miranda J. Munoz; Rishabh Arora; Yessenia M. Rivera; Quentin H. Drane; Gian D. Pal; Leo Verhagen Metman; Sepehr B. Sani; Joshua M. Rosenow; Lisa C. Goelz; Daniel M. Corcos; Fabian J. David In: Frontiers in Neurology, vol. 15, pp. 1–7, 2024. @article{Munoz2024a,Introduction: The long-term effects of surgery for subthalamic nucleus deep brain stimulation (STN-DBS) on cognitive aspects of motor control for people with Parkinson's disease (PD) are largely unknown. We compared saccade latency and reach reaction time (RT) pre- and post-surgery while participants with PD were off-treatment. Methods: In this preliminary study, we assessed people with PD approximately 1 month pre-surgery while OFF medication (OFF-MEDS) and about 8 months post-surgery while OFF medication and STN-DBS treatment (OFF-MEDS/OFF-DBS). We examined saccade latency and reach reaction time (RT) performance during a visually-guided reaching task requiring participants to look at and reach toward a visual target. Results: We found that both saccade latency and reach RT significantly increased post-surgery compared to pre-surgery. In addition, there was no significant change in Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III score. Discussion: We found detrimental post-surgical changes to saccade latency and reach RT. We discuss the potential contributions of long-term tissue changes and withdrawal from STN-DBS on this detrimental cognitive effect. |
Miranda J. Munoz; James L. Reilly; Gian D. Pal; Leo Verhagen Metman; Sepehr B. Sani; Joshua M. Rosenow; Yessenia M. Rivera; Quentin H. Drane; Lisa C. Goelz; Daniel M. Corcos; Fabian J. David In: Clinical Neurophysiology, vol. 162, pp. 41–52, 2024. @article{Munoz2024b,Objective: We aimed to gain further insight into previously reported beneficial effects of subthalamic nucleus deep brain stimulation (STN-DBS) on visually-guided saccades by examining the effects of unilateral compared to bilateral stimulation, paradigm, and target eccentricity on saccades in individuals with Parkinson's disease (PD). Methods: Eleven participants with PD and STN-DBS completed the visually-guided saccade paradigms with OFF, RIGHT, LEFT, and BOTH stimulation. Rightward saccade performance was evaluated for three paradigms and two target eccentricities. Results: First, we found that BOTH and LEFT increased gain, peak velocity, and duration compared to OFF stimulation. Second, we found that BOTH and LEFT stimulation decreased latency during the gap and step paradigms but had no effect on latency during the overlap paradigm. Third, we found that RIGHT was not different compared to OFF at benefiting rightward saccade performance. Conclusions: Left unilateral and bilateral stimulation both improve the motor outcomes of rightward visually-guided saccades. Additionally, both improve latency, a cognitive-motor outcome, but only in paradigms when attention does not require disengagement from a present stimulus. Significance: STN-DBS primarily benefits motor and cognitive-motor aspects of visually-guided saccades related to reflexive attentional shifting, with the latter only evident when the fixation-related attentional system is not engaged. |
Krishnaveni Nagarajan; Kavya Ravi; Shakthi Pradheepa Periakaruppan; Prem Nandhini Satgunam When noise becomes signal: A study of blink rate using an eye tracker Journal Article In: The Ocular Surface, vol. 34, pp. 516–520, 2024. @article{Nagarajan2024,Purpose: Although blink rate is considered important for digital eye strain and dry eye conditions, its assessment has been mostly manual. This study aimed at quantifying blink rate automatically using the Eyelink 1000 Plus eye tracker and comparing it with manual counting. Additionally, blink rate was correlated with reading eye movements and reading speed. Methods: Thirty participants (mean age 26.8 ± 3.5 years; 19 females) were enrolled. An on-screen reading task for 3 min duration, was repeated 3 times with a 2-min break between the repetitions. During this task, eye movements and blinks were measured through the Eyelink 1000 Plus eye tracker. The blink was also counted manually by the examiner in real time from a video feed. Results: The blink rate obtained by the eye tracker (median [Q1, Q3]:11.7 [6.8,15.5] blinks/min) and manual counting (11.6 [7.1, 15.4] blinks/min) were comparable (p > 0.5). No significant correlations were observed between the blink rate and any of the reading eye movement parameters except saccadic amplitude (Spearman's rho |
Tal Nahari; Eran Eldar; Yoni Pertzov Fixation durations on familiar items are longer due to attenuation of exploration Journal Article In: Cognitive Research: Principles and Implications, vol. 9, no. 1, pp. 1–11, 2024. @article{Nahari2024,Previous studies have shown that fixations on familiar stimuli tend to be longer than on unfamiliar stimuli, theorized to be a result of retrieval of information from memory. We hypothesize that extended fixations are due to a lesser need to explore an already familiar stimulus. Participant's gaze was tracked as they tried to encode or retrieve a familiar face displayed either alone or alongside other unfamiliar faces. Regardless of the memory task (encoding$backslash$retrieval), longer fixation durations were observed when a single familiar face was presented alone, and not when presented among unfamiliar ones. Thus, fixations were not prolonged when it was possible to explore other, unfamiliar stimuli. We conclude that prolonged fixations on familiar stimuli reflect a lesser need to explore an already familiar percept. The results underscore how memory representations influence active sensing, yielding fresh insights into efficient deployment of attention resources. We conclude that fixation durations could be used in applied memory detection tests, preferably together with other measures and when the familiar stimulus is presented alone. |
Hamideh Norouzi; Mohammad Reza Daliri Prediction of behavioral performance by alpha-band phase synchronization in working memory Journal Article In: Physiology and Behavior, vol. 284, pp. 1–11, 2024. @article{Norouzi2024,Working memory (WM) is a cognitive system with limited capacity that can temporarily store and process information. The purpose of this study was to investigate functional connectivity based on phase synchronization during WM and its relationship with the behavioral response. In this regard, we recorded EEG/Eye tracking data of seventeen healthy subjects while performing a memory-guided saccade (MGS) task with two different positions (near eccentricity and far eccentricity). We computed saccade error as memory performance and measured functional connectivity using Phase Locking Value (PLV) in the alpha frequency band (8–12 Hz). The results showed that PLV is negatively correlated with saccade error. Our finding indicated that during the maintenance period, PLV between the frontal and visual area in trials with low saccade error increased significantly compared to trials with high saccade error. Furthermore, we observed a significant difference between PLV for near and far conditions in the delay period. The results suggest that PLV in memory maintenance, in addition to predicting saccade error as behavioral performance, can be related to the coding of spatial information in WM. |
Sven Ohl; Lisa M. Kroell; Martin Rolfs In: Journal of Experimental Psychology: General, vol. 153, no. 2, pp. 544–563, 2024. @article{Ohl2024,Visual working memory and actions are closely intertwined. Memory can guide our actions, but actions also impact what we remember. Even during memory maintenance, actions such as saccadic eye movements select content in visual working memory, resulting in better memory at locations that are congruent with the action goal as compared to incongruent locations. Here, we further substantiate the claim that saccadic eye movements are fundamentally linked to visual working memory by analyzing a large data set (.100k trials) of nine experiments (eight of them previously published). Using Bayesian hierarchical models, we demonstrate robust saccadic selection across the full range of probed saccade directions, manifesting as better memory performance at the saccade goal irrespective of its location in the visual field. By inspecting individual differences in saccadic selection, we show that saccadic selection was highly prevalent in the population. Moreover, both saccade metrics and visual working memory performance varied considerably across the visual field. Crucially, however, both idiosyncratic and systematic visual field anisotropies were not correlated between visual working memory and the oculomotor system, suggesting that they resulted from different sources (e.g., rely on separate spatial maps). In stark contrast, trial-by-trial variations in saccade metrics were strongly associated with memory performance: At any given location, shorter saccade latencies and more accurate saccades were associated with better memory performance, undergirding a robust link between action selection and visual memory. |
Coleman E. Olenick; Heather Jordan; Mazyar Fallah Identifying a distractor produces object-based inhibition in an allocentric reference frame for saccade planning Journal Article In: Scientific Reports, vol. 14, no. 1, pp. 1–12, 2024. @article{Olenick2024,We investigated whether distractor inhibition occurs relative to the target or fixation in a perceptual decision-making task using a purely saccadic response. Previous research has shown that during the process of discriminating a target from distractor, saccades made to a target deviate towards the distractor. Once discriminated, the distractor is inhibited, and trajectories deviate away from the distractor. Saccade deviation magnitudes provide a sensitive measure of target-distractor competition dependent on the distance between them. While saccades are planned in an egocentric reference frame (locations represented relative to fixation), object-based inhibition has been shown to occur in an allocentric reference frame (objects represented relative to each other independent of fixation). By varying the egocentric and allocentric distances of the target and distractor, we found that only egocentric distances contributed to saccade trajectories shifts towards the distractor during active decision-making. When the perceptual decision-making process was complete, and the distractor was inhibited, both ego- and allocentric distances independently contributed to saccade trajectory shifts away from the distractor. This is consistent with independent spatial and object-based inhibitory mechanisms. Therefore, we suggest that distractor inhibition is maintained in cortical visual areas with allocentric maps which then feeds into oculomotor areas for saccade planning. |
Isabella F. Orlando; Frank H. Hezemans; Rong Ye; Alexander G. Murley; Negin Holland; Ralf Regenthal; Roger A. Barker; Caroline H. Williams-Gray; Luca Passamonti; Trevor W. Robbins; James B. Rowe; Claire O'Callaghan Noradrenergic modulation of saccades in Parkinson's disease Journal Article In: Brain Communications, vol. 6, no. 5, pp. 1–13, 2024. @article{Orlando2024,Noradrenaline is a powerful modulator of cognitive processes, including action-decisions underlying saccadic control. Changes in saccadic eye movements are common across neurodegenerative diseases of ageing, including Parkinson's disease. With growing interest in noradrenergic treatment potential for non-motor symptoms in Parkinson's disease, the temporal precision of oculomotor function is advantageous to assess the effects of this modulation. Here we studied the effect of 40 mg atomoxetine, a noradrenaline reuptake inhibitor, in nineteen people with idiopathic Parkinson's disease using a single dose, randomised double-blind crossover placebo-controlled design. Twenty-five healthy adult participants completed the assessments to provide normative data. Participants performed prosaccade and antisaccade tasks. The latency, velocity and accuracy of saccades, and resting pupil diameter, were measured. Increased pupil diameter on the drug confirmed its expected effect on the locus coeruleus ascending arousal system. Atomoxetine altered key aspects of saccade performance: prosaccade latencies were faster and the saccadic main sequence was normalised. These changes were accompanied by increased antisaccade error rates on the drug. Together these findings suggest a shift in the speed-accuracy trade-off for visuo-motor decisions in response to noradrenergic treatment. Our results provide new evidence to substantiate a role for noradrenergic modulation of saccades, and based on known circuitry we advance the hypothesis that this reflects modulation at the level of the locus coeruleus–superior colliculus pathway. Given the potential for noradrenergic treatment of non-motor symptoms of Parkinson's disease and related conditions, the oculomotor system can support the assessment of cognitive effects without limb-motor confounds on task performance. |
Michael L. Paavola; Andrew Hollingworth; Cathleen M. Moore Saccades to partially occluded objects: Perceptual completion mediates oculomotor control Journal Article In: Journal of Vision, vol. 24, no. 3, pp. 1–17, 2024. @article{Paavola2024,Oculomotor behavior typically consists of directing gaze to objects in complex scenes for the purpose of extracting detailed perceptual information. Here, we probed the nature of the visual representations over which saccades to objects are computed. We contrasted an image-based oculomotor control hypothesis, holding that saccades are computed solely over information explicit in the retinal image, and an object-based oculomotor control hypothesis, holding that saccades are computed over object representations reflecting the three-dimensional structure of the scene. We recorded saccade landing positions to partially occluded objects in a naturalistic search task. In Experiment 1, saccade landing positions were biased toward the center of the perceptually completed object. Experiment 2 demonstrated that the bias held even when it would have been strategically advantageous to avoid it. Experiment 3 demonstrated that the bias was not due to image-level differences generated by the presence of occluders. The results indicate that saccade motor programs are computed, at least in part, over object-level representations reflecting the completion of occluded surfaces. |
Yunxian Pan; Jie Xu Gaze-based human intention prediction in the hybrid foraging search task Journal Article In: Neurocomputing, vol. 587, pp. 1–13, 2024. @article{Pan2024c,An agent's ability to predict a human's intention can facilitate the effectiveness of a human-agent team. The aim of this study was to explore the feasibility of predicting human intention in the hybrid foraging search task using eye gaze data and machine learning. In the hybrid foraging search paradigm, the human performs searches in patches and decides to stay and exploit a patch or to leave and explore another patch. Researchers have modeled the “patch-leaving problem” on the collective level using the marginal value theorem. However, few have attempted to predict the exact moment when the human will leave. In the current study, 40 participants performed the hybrid foraging search task while eye gaze data were collected with an eye-tracker. The leaving intention was associated with larger pupil size, shorter average fixation duration, larger number of fixations, longer saccade amplitude, and faster saccade velocity compared to the searching intention. A cross-subject machine learning model with an artificial neural network algorithm was able to predict whether a participant would leave the current patch with up to 78% accuracy with a 2-second data analysis window. The length of the data analysis window did not significantly affect prediction accuracy. Furthermore, the earlier the behavior prediction was made, the lower the reliability of the prediction. These results demonstrate that eye gaze features and machine learning algorithms are useful in predicting human intention in visual search tasks. |
Christos Papanikolaou; Akriti Sharma; Pedro G. Lind; Pedro Lencastre Lévy flight model of gaze trajectories to assist in ADHD diagnoses Journal Article In: Entropy, vol. 26, no. 5, pp. 1–13, 2024. @article{Papanikolaou2024,The precise mathematical description of gaze patterns remains a topic of ongoing debate, impacting the practical analysis of eye-tracking data. In this context, we present evidence supporting the appropriateness of a Lévy flight description for eye-gaze trajectories, emphasizing its beneficial scale-invariant properties. Our study focuses on utilizing these properties to aid in diagnosing Attention-Deficit and Hyperactivity Disorder (ADHD) in children, in conjunction with standard cognitive tests. Using this method, we found that the distribution of the characteristic exponent of Lévy flights statistically is different in children with ADHD. Furthermore, we observed that these children deviate from a strategy that is considered optimal for searching processes, in contrast to non-ADHD children. We focused on the case where both eye-tracking data and data from a cognitive test are present and show that the study of gaze patterns in children with ADHD can help in identifying this condition. Since eye-tracking data can be gathered during cognitive tests without needing extra time-consuming specific tasks, we argue that it is in a prime position to provide assistance in the arduous task of diagnosing ADHD. |
Anita Paparelli; Nayla Sokhn; Lisa Stacchi; Antoine Coutrot; Anne Raphaëlle Richoz; Roberto Caldara Idiosyncratic fixation patterns generalize across dynamic and static facial expression recognition Journal Article In: Scientific Reports, vol. 14, no. 1, pp. 1–13, 2024. @article{Paparelli2024,Facial expression recognition (FER) is crucial for understanding the emotional state of others during human social interactions. It has been assumed that humans share universal visual sampling strategies to achieve this task. However, recent studies in face identification have revealed striking idiosyncratic fixation patterns, questioning the universality of face processing. More importantly, very little is known about whether such idiosyncrasies extend to the biological relevant recognition of static and dynamic facial expressions of emotion (FEEs). To clarify this issue, we tracked observers' eye movements categorizing static and ecologically valid dynamic faces displaying the six basic FEEs, all normalized for time presentation (1 s), contrast and global luminance across exposure time. We then used robust data-driven analyses combining statistical fixation maps with hidden Markov Models to explore eye-movements across FEEs and stimulus modalities. Our data revealed three spatially and temporally distinct equally occurring face scanning strategies during FER. Crucially, such visual sampling strategies were mostly comparably effective in FER and highly consistent across FEEs and modalities. Our findings show that spatiotemporal idiosyncratic gaze strategies also occur for the biologically relevant recognition of FEEs, further questioning the universality of FER and, more generally, face processing. |
Jagruti J. Pattadkal; Carrie Barr; Nicholas J. Priebe Interactions between saccades and smooth pursuit eye movements in marmosets Journal Article In: eNeuro, vol. 11, no. 6, pp. 1–11, 2024. @article{Pattadkal2024,Animals use a combination of eye movements to track moving objects. These different eye movements need to be coordinated for successful tracking, requiring interactions between the systems involved. Here, we study the interaction between the saccadic and smooth pursuit eye movement systems in marmosets. Using a single-target pursuit task, we show that saccades cause an enhancement in pursuit following a saccade. Using a two-target pursuit task, we show that this enhancement in pursuit is selective toward the motion of the target selected by the saccade, irrespective of any biases in pursuit prior to the saccade. These experiments highlight the similarities in the functioning of saccadic and smooth pursuit eye movement systems across primates. |
Vasiliki Bougou; Michaël Vanhoyland; Alexander Bertrand; Wim Van Paesschen; Hans Op De Beeck; Peter Janssen; Tom Theys Neuronal tuning and population representations of shape and category in human visual cortex Journal Article In: Nature Communications, vol. 15, no. 1, pp. 1–15, 2024. @article{Bougou2024,Object recognition and categorization are essential cognitive processes which engage considerable neural resources in the human ventral visual stream. However, the tuning properties of human ventral stream neurons for object shape and category are virtually unknown. We performed large-scale recordings of spiking activity in human Lateral Occipital Complex in response to stimuli in which the shape dimension was dissociated from the category dimension. Consistent with studies in nonhuman primates, the neuronal representations were primarily shape-based, although we also observed category-like encoding for images of animals. Surprisingly, linear decoders could reliably classify stimulus category even in data sets that were entirely shape-based. In addition, many recording sites showed an interaction between shape and category tuning. These results represent a detailed study on shape and category coding at the neuronal level in the human ventral visual stream, furnishing essential evidence that reconciles human imaging and macaque single-cell studies. |
Andy Brendler; Max Schneider; Immanuel G. Elbau; Rui Sun; Taechawidd Nantawisarakul; Dorothee Pöhlchen; Tanja Brückl; A. K. Brem; E. B. Binder; A. Erhardt; J. Fietz; N. C. Grandi; Y. Kim; S. Ilić-Ćoćić; L. Leuchs; S. Lucae; T. Namendorf; J. Pape; L. Schilbach; I. Mücke-Heim; J. Ziebula; Michael Czisch; Philipp G. Sämann; Michael D. Lee; Victor I. Spoormaker In: Scientific Reports, vol. 14, no. 344, pp. 1–11, 2024. @article{Brendler2024,Major depressive disorder (MDD) is a devastating and heterogenous disorder for which there are no approved biomarkers in clinical practice. We recently identified anticipatory hypo-arousal indexed by pupil responses as a candidate mechanism subserving depression symptomatology. Here, we conducted a replication and extension study of these findings. We analyzed a replication sample of 40 unmedicated patients with a diagnosis of depression and 30 healthy control participants, who performed a reward anticipation task while pupil responses were measured. Using a Bayesian modelling approach taking measurement uncertainty into account, we could show that the negative correlation between pupil dilation and symptom load during reward anticipation is replicable within MDD patients, albeit with a lower effect size. Furthermore, with the combined sample of 136 participants (81 unmedicated depressed and 55 healthy control participants), we further showed that reduced pupil dilation in anticipation of reward is inversely associated with anhedonia items of the Beck Depression Inventory in particular. Moreover, using simultaneous fMRI, particularly the right anterior insula as part of the salience network was negatively correlated with depressive symptom load in general and anhedonia items specifically. The present study supports the utility of pupillometry in assessing noradrenergically mediated hypo-arousal during reward anticipation in MDD, a physiological process that appears to subserve anhedonia. |
Holly Bridge; Abigail Wyllie; Aaron Kay; Bailey Rand; Lucy Starling; Rebecca S. Millington-Truby; William T. Clarke; Jasleen K. Jolly; I. Betina Ip Neurochemistry and functional connectivity in the brain of people with Charles Bonnet syndrome Journal Article In: Therapeutic Advances in Ophthalmology, vol. 16, pp. 1–18, 2024. @article{Bridge2024,Background: Charles Bonnet syndrome (CBS) is a condition in which people with vision loss experience complex visual hallucinations. These complex visual hallucinations may be caused by increased excitability in the visual cortex that are present in some people with vision loss but not others. Objectives: We aimed to evaluate the association between γ-aminobutyric acid (GABA) in the visual cortex and CBS. We also tested the relationship among visually evoked responses, functional connectivity, and CBS. Design: This is a prospective, case-controlled, cross-sectional observational study. Methods: We applied 3-Tesla magnetic resonance spectroscopy, as well as task-based and resting state (RS) connectivity functional magnetic resonance imaging in six participants with CBS and six controls without CBS. GABA+ was measured in the early visual cortex (EVC) and in the lateral occipital cortex (LOC). Participants also completed visual acuity and cognitive tests, and the North-East Visual Hallucinations Interview. Results: The two groups were well-matched for age, gender, visual acuity and cognitive scores. There was no difference in GABA+ levels between groups in the visual cortex. Most participants showed the expected blood oxygenation level dependent (BOLD) activation to images of objects and the phase-scrambled control. Using a fixed effects analysis, we found that BOLD activation was greater in participants with CBS compared to controls. Analysis of RS connectivity with LOC and EVC showed little difference between groups. A fixed effects analysis showed a correlation between the extent of functional connectivity with LOC and hallucination strength. Conclusion: Overall, our results provide no strong evidence for an association between GABAergic inhibition in the visual cortex and CBS. We only found subtle differences in visual function and connectivity between groups. These findings suggest that the neurochemistry and visual connectivity for people with Charles Bonnet hallucinations are comparable to a sight loss population. Differences between groups may emerge when investigating subtle and transient changes that occur at the time of visual hallucinations. |
Gokce Busra Cakir; Jordan Murray; Cody Dulaney; Fatema Ghasia Multifaceted interactions of stereoacuity, inter-ocular suppression, and fixation eye movement abnormalities in amblyopia and strabismus Journal Article In: Investigative Ophthalmology & Visual Science, vol. 65, no. 3, pp. 1–20, 2024. @article{Cakir2024,PURPOSE. Amblyopic and strabismus subjects experience inter-ocular suppression, impaired stereoacuity, and increased fixation instability. The purpose of the study was to investigate factors affecting suppression and stereoacuity and examine their relationship to fixation eye movement (FEM) abnormalities. METHODS. We recruited 14 controls and 46 amblyopic subjects (anisometropic = 18 |
Runnan Cao; Peter Brunner; Puneeth N. Chakravarthula; Krista Wahlstrom; Cory Inman; Elliot H. Smith; Xin Li; Adam N. Mamelak; Nicholas Brandmeir; Ueli Rutishauser; Jon T. Willie; Shuo Wang A neuronal code for object representation and memory in the human amygdala and hippocampus Journal Article In: Nature Communications, vol. 16, no. 1, pp. 1–16, 2024. @article{Cao2024b,How the brain encodes, recognizes, and memorizes general visual objects is a fundamental question in neuroscience. Here, we investigated the neural processes underlying visual object perception and memory by recording from 3173 single neurons in the human amygdala and hippocampus across four experiments. We employed both passive-viewing and recognition memory tasks involving a diverse range of naturalistic object stimuli. Our findings reveal a region-based feature code for general objects, where neurons exhibit receptive fields in the high-level visual feature space. This code can be validated by independent new stimuli and replicated across all experiments, including fixation-based analyses with large natural scenes. This region code explains the long-standing visual category selectivity, preferentially enhances memory of encoded stimuli, predicts memory performance, encodes image memorability, and exhibits intricate interplay with memory contexts. Toge-ther, region-based feature coding provides an important mechanism for visual object processing in the human brain. |
Runnan Cao; Peter Brunner; Shuo Wang; Jinge Wang; Peter Brunner; Jon T. Willie; Xin Li; Ueli Rutishauser; Nicholas J. Brandmeir; Shuo Wang Neural mechanisms of face familiarity and learning in the human amygdala and hippocampus Journal Article In: Cell Reports, vol. 43, no. 1, pp. 1–36, 2024. @article{Cao2024c,Recognizing familiar faces and learning new faces play an important role in social cognition. However, the underlying neural computational mechanisms remain unclear. Here, we record from single neurons in the human amygdala and hippocampus and find a greater neuronal representational distance between pairs of familiar faces than unfamiliar faces, suggesting that neural representations for familiar faces are more distinct. Representational distance increases with exposures to the same identity, suggesting that neural face representations are sharpened with learning and familiarization. Furthermore, representational distance is positively correlated with visual dissimilarity between faces, and exposure to visually similar faces increases representational distance, thus sharpening neural representations. Finally, we construct a computational model that demonstrates an increase in the representational distance of artificial units with training. Together, our results suggest that the neuronal population geometry, quantified by the representational distance, encodes face familiarity, similarity, and learning, forming the basis of face recognition and memory. |
Matthew R. Cavanaugh; Marisa Carrasco; Krystel R. Huxlin Exogenous spatial attention helps overcome spatial specificity of visual learning in the blind field after v1 damage Journal Article In: Journal of Cognitive Enhancement, no. 0123456789, 2024. @article{Cavanaugh2024,Visual discrimination training can restore visual functions in the blind field of participants with stroke-induced V1 damage. However, single-stimulus training in this population is limited by spatial specificity. Thus, it requires iterative training over several months to achieve improvement at more than one blind-field location, particularly at sites further from the blind field border (i.e., deeper in the blind field). With neurotypical observers, exogenous spatial attention (SA) facilitates transfer of learning to untrained locations. Here, we asked if SA pre-cues could induce transfer of training deeper into cortically blinded (CB) fields. Twenty CB participants trained on a global motion discrimination task either using a single [primary] stimulus and no cues (Task 1), a single primary stimulus with a large pre-cue deep in the blind field (Task 2), two identical stimuli (primary and deep) with small pre-cues just above them (Task 3), or a single stimulus randomly alternating at a primary and deep blind-field location, forewarned by a small pre-cue above them on each trial (Task 4). Training on Task 1 induced reliable improvements at the primary location, but no transfer of learning deeper in the blind field. The addition of SA pre-cues in Tasks 2–4 induced transfer in more than half the participants, although threshold improvements at primary locations were smaller than for Task 1. We conclude that directing exogenous SA deep in the blind field attracts attention automatically in CB patients and facilitates transfer of learning towards cued locations, even without V1 processing for those regions of space. |
Melinda Y. Chang; Mark S. Borchert Comparison of eye tracking and Teller acuity cards for visual acuity assessment in pediatric cortical/cerebral visual impairment (CVI) Journal Article In: American Journal of Ophthalmology, vol. 260, pp. 115–121, 2024. @article{Chang2024a,PURPOSE: To compare eye tracking and Teller acuity cards (TAC) for assessment of visual acuity in children with cortical, or cerebral, visual impairment (CVI). DESIGN: Reliability and validity study. METHODS: We recruited 41 children with CVI from a single academic pediatric neuro-ophthalmology clinic. All children performed eye tracking to measure visual acuity, and 26 children completed TAC assessment by a masked examiner. Additionally, 2 pediatric neuro-ophthalmologists graded visual behavior using the 6-level Visual Behavior Scale (VBS). Eye tracking and TAC were performed at baseline and at 1 month. Test–retest reliability of eye tracking and TAC were assessed using the intraclass correlation coefficient (ICC). Eye tracking and TAC visual acuities were correlated with one another and VBS scores using the Spearman correlation coefficient. RESULTS: Test–retest reliability was excellent for eye tracking measurement of visual acuity (ICC = 0.81, P <.0001). For pediatric CVI, TAC test–retest reliability was fair (ICC = 0.42 |
Sarah E. Colby; Francis X. Smith; Bob McMurray The role of inhibitory control in spoken word recognition: Evidence from cochlear implant users Journal Article In: Language, Cognition and Neuroscience, vol. 39, no. 8, pp. 1059–1071, 2024. @article{Colby2024,During spoken word recognition, listeners must quickly map sounds to meaning while suppressing competitors. It remains unclear whether domain-general inhibitory control is recruited for resolving lexical competition. Cochlear implant (CI) users present a unique population for addressing this question because they are consistently confronted with degraded auditory input, and may need to rely on domain-general mechanisms to compensate. We examined word recognition in adult CI users who were prelingually deaf (lost their hearing in childhood |
Carmen Julia Coloma; Ernesto Guerra; Zulema De Barbieri; Andrea Helo; Zulema De Barbieri; Andrea Helo; Carmen Julia; Ernesto Guerra; Zulema De Barbieri; Andrea Helo Article comprehension in monolingual Spanish-speaking children with developmental language disorder: A longitudinal eye tracking study Journal Article In: International Journal of Speech-Language Pathology, vol. 26, no. 1, pp. 105–117, 2024. @article{Coloma2024,Purpose: Article-noun disagreement in spoken language is a marker of children with developmental language disorder (DLD). However, the evidence is less clear regarding article comprehension. This study investigates article comprehension in monolingual Spanish-speaking children with and without DLD. Method: Eye tracking methodology used in a longitudinal experimental design enabled the examination of real time article comprehension. The children at the time 1 were 40 monolingual Spanish-speaking preschoolers (20 with DLD and 20 with typical language development [TLD]). A year later (time 2), 27 of these children (15 with DLD and 12 with TLD) were evaluated. Children listened to simple phrases while inspecting a four object visual context. The article in the phrase agreed in number and gender with only one of the objects. Result: At the time 1, children with DLD did not use articles to identify the correct image, while children with TLD anticipated the correct picture. At the time 2, both groups used the articles' morphological markers, but children with DLD showed a slower and weaker preference for the correct referent compared to their age-matched peers. Conclusion: These findings suggest a later emergence, but a similar developmental trajectory, of article comprehension in children with DLD compared to their peers with TLD. |
Bing Dai; Kwang Meng Cham; Larry Allen Abel Visual search in infantile nystagmus syndrome Journal Article In: Clinical and Experimental Optometry, vol. 107, no. 6, pp. 641–648, 2024. @article{Dai2024,Clinical relevance: Research on infantile nystagmus syndrome (INS) and visual search is limited. Conducting this research could assist practitioners in understanding how INS affects the real-life visual activities of patients and aid in developing new clinical visual function assessments for INS. Background: The aim of this work is to investigate how subjects with INS perform visual search tasks, and, particularly, to assess how INS subjects perform when targets are located at their null position or away from it, and when under additional cognitive demands. Methods: INS subjects (N = 15) and controls (N = 20) performed conjunction and feature search tasks, both with and without mental arithmetic. Search performance was assessed using log-transformed total search time, gaze-dependent search time, and accuracy. Cognitive demand was quantified by pupil size and the NASA task-load index score. Results: INS subjects showed longer search times compared to controls in conjunction search (P < 0.01), but not in feature search. Within INS and control subjects, the total search times were significantly increased by the addition of mental arithmetic (P < 0.0001). There was no difference in gaze-dependent search times between null target position and 15° away from null target position of subjects in conjunction search (P > 0.05). Accuracies were 100% for both control and INS subjects in both conjunction and feature search. Conclusion: Conjunction visual search was impaired in adult INS subjects, and further worsened under increased cognitive demand. The null position did not affect the visual search performance in INS. |
Elizabeth H. X. Thomas; Susan L. Rossell; Jessica B. Myles; Eric J. Tan; Erica Neill; Sean P. Carruthers; Philip J. Sumner; Kiymet Bozaoglu; Caroline Gurvich The relationship of schizotypy and saccade performance in patients with schizophrenia and non-clinical individuals Journal Article In: Journal of Individual Differences, vol. 45, no. 4, pp. 244–254, 2024. @article{Thomas2024,Deficits in saccade performance (i.e., rapid eye movements) are commonly observed in people with schizophrenia. Investigations of the schizotypy-saccade relationship have been exclusively explored in non-clinical individuals, with mixed findings. Of the three saccadic paradigms, research has predominantly focused on the antisaccade paradigm, while the relationship between schizotypy and prosaccade and memory-guided saccade performance remains underexplored. This study aimed to investigate the relationship between schizotypy and saccade performance across the three saccadic paradigms in both patients and non-clinical individuals. Sixty-two patients with schizophrenia/schizoaffective disorder and 148 non-clinical individuals completed the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE) self-report questionnaire as a measure of schizotypy. All participants also completed a prosaccade, memory-guided saccade and antisaccade task. Canonical correlation analyses were conducted to examine the collective, multivariate relationship between the set of schizotypy variables and the sets of prosaccade, memory-guided saccade and antisaccade variables. Differences between patients and non-clinical groups were in line with previous research. In the non-clinical group, Cognitive Disorganisation was the highest contributing variable to prosaccade performance and prosaccade latency was the highest contributing variable to schizotypy. There was no significant relationship between schizotypy and memory-guided or antisaccade performance. No significant relationships between schizotypy and saccade performance were observed in the patient group. Our findings suggest a relationship between disorganized schizotypy and basic processing speed in non-clinical individuals. This relationship was not observed in patients, suggesting that sub-clinical saccade performance may not mirror impairments observed in schizophrenia. Our findings in the non-clinical group were inconsistent with previous studies. These used different schizotypy inventories, suggesting that schizotypy measures derived from different conceptual backgrounds may not be comparable. |
Christof Elias Topfstedt; Luca Wollenberg; Thomas Schenk Training enables substantial decoupling of visual attention and saccade preparation Journal Article In: Vision Research, vol. 221, pp. 1–13, 2024. @article{Topfstedt2024,Visual attention is typically shifted toward the targets of upcoming saccadic eye movements. This observation is commonly interpreted in terms of an obligatory coupling between attentional selection and oculomotor programming. Here, we investigated whether this coupling is facilitated by a habitual expectation of spatial congruence between visual and motor targets. To this end, we conducted a dual-task (i.e., concurrent saccade task and visual discrimination task) experiment in which male and female participants were trained to either anticipate spatial congruence or incongruence between a saccade target and an attention probe stimulus. To assess training-induced effects of expectation on premotor attention allocation, participants subsequently completed a test phase in which the attention probe position was randomized. Results revealed that discrimination performance was systematically biased toward the expected attention probe position, irrespective of whether this position matched the saccade target or not. Overall, our findings demonstrate that visual attention can be substantially decoupled from ongoing oculomotor programming and suggest an important role of habitual expectations in the attention-action coupling. |
Sandra Tyralla; Eckart Zimmermann Serial dependencies in motor targeting as a function of target appearance Journal Article In: Journal of Vision, vol. 24, no. 13, pp. 1–13, 2024. @article{Tyralla2024,In order to bring stimuli of interest into our central field of vision, we perform saccadic eye movements. After every saccade, the error between the predicted and actual landing position is monitored. In the laboratory, artificial post-saccadic errors are created by displacing the target during saccade execution. Previous research found that even a single post-saccadic error induces immediate amplitude changes to minimize that error. The saccadic amplitude adjustment could result from a recalibration of the saccade target representation. We asked if recalibration follows an integration scheme in which the impact magnitude of the previous post-saccadic target location depends on the certainty of the current target. We asked subjects to perform saccades to Gaussian blobs as targets, the visuospatial certainty of which we manipulated by changing its spatial constant. In separate sessions, either the pre-saccadic or post-saccadic target was uncertain. Additionally, we manipulated the contrast to further decrease certainty, changing the spatial constant mid-saccade. We found saccade-by-saccade amplitude reductions only with a currently uncertain target, a previously certain one, and a constant target contrast. We conclude that the features of the pre-saccadic target (i.e., size and contrast) determine the extent to which post-saccadic error shapes upcoming saccade amplitudes. |
Hariklia Vagias; Michelle L. Byrne; Lyn Millist; Owen White; Meaghan Clough; Joanne Fielding Visuo-cognitive phenotypes in early multiple sclerosis: A multisystem model of visual processing Journal Article In: Journal of Clinical Medicine, vol. 13, no. 3, pp. 1–19, 2024. @article{Vagias2024,Background: Cognitive impairment can emerge in the earliest stages of multiple sclerosis (MS), with heterogeneity in cognitive deficits often hindering symptom identification and management. Sensory–motor dysfunction, such as visual processing impairment, is also common in early disease and can impact neuropsychological task performance in MS. However, cognitive phenotype research in MS does not currently consider the relationship between early cognitive changes and visual processing impairment. Objectives: This study explored the relationship between cognition and visual processing in early MS by adopting a three-system model of afferent sensory, central cognitive and efferent ocular motor visual processing to identify distinct visuo-cognitive phenotypes. Methods: Patients with clinically isolated syndrome and relapsing–remitting MS underwent neuro-ophthalmic, ocular motor and neuropsychological evaluation to assess each visual processing system. The factor structure of ocular motor variables was examined using exploratory factor analysis, and phenotypes were identified using latent profile analysis. Results: Analyses revealed three ocular-motor constructs (cognitive control, cognitive processing speed and basic visual processing) and four visuo-cognitive phenotypes (early visual changes, efferent-cognitive, cognitive control and afferent-processing speed). While the efferent-cognitive phenotype was present in significantly older patients than was the early visual changes phenotype, there were no other demographic differences between phenotypes. The efferent-cognitive and cognitive control phenotypes had poorer performance on the Symbol Digit Modalities Test compared to that of other phenotypes; however, no other differences in performance were detected. Conclusion: Our findings suggest that distinct visual processing deficits in early MS may differentially impact cognition, which is not captured using standard neuropsychological evaluation. Further research may facilitate improved symptom identification and intervention in early disease. |
Simone Viganò; Rena Bayramova; Christian F. Doeller; Roberto Bottini Spontaneous eye movements reflect the representational geometries of conceptual spaces Journal Article In: Proceedings of the National Academy of Sciences, vol. 121, no. 17, pp. 1–10, 2024. @article{Vigano2024,Functional neuroimaging studies indicate that the human brain can represent concepts and their relational structure in memory using coding schemes typical of spatial navigation. However, whether we can read out the internal representational geometries of conceptual spaces solely from human behavior remains unclear. Here, we report that the relational structure between concepts in memory might be reflected in spontaneous eye movements during verbal fluency tasks: When we asked participants to randomly generate numbers, their eye movements correlated with distances along the left- to- right one- dimensional geometry of the number space (mental number line), while they scaled with distance along the ring- like two- dimensional geometry of the color space (color wheel) when they randomly generated color names. Moreover, when participants ran- domly produced animal names, eye movements correlated with low- dimensional sim- ilarity in word frequencies. These results suggest that the representational geometries used to internally organize conceptual spaces might be read out from gaze behavior. |