BACKGROUND:Fixation stability (FS) is a basic substrate of visuomotor processing that can be assessed by tracking eye movements during a simple, easy-to-perform task of gazing at a visual stimulus. We studied FS with and without distractors for its potential as an endophenotype marker in antipsychotic-naïve/free schizophrenia (SCZ), SCZ first-degree relatives (FDRs), and healthy controls (HC). METHOD:Monocular high-frequency eye tracking data were recorded during a fixation stability task in 69 antipsychotic-naïve/free SCZ, 49 FDRs, and 76 HCs. The task required maintenance of gaze on a central circular target while ignoring an identical peripheral distractor, when present, at near/farther distances on either side. Fixation stability across the groups and the effect of laterality and distance of the distractor effect were analyzed using ANCOVA and RMANCOVA. RESULT:SCZ had significantly higher fixation frequency, saccade amplitude, and scanpath length compared to the other groups, even in trials without distractors (ηp2 = 0.05-0.07). Introducing distractors resulted in further worsening of performance in SCZ (ηp2 = 0.09-0.23). First-degree relatives showed impairment in median fixation duration (ηp2 = 0.13). Higher saccade amplitudes and scanpath lengths (both ηp2 = 0.09) were noted in trials with farther distractors across the groups. A significant interaction effect of the laterality * group was noted on scanpath length (ηp2 = 0.03). DISCUSSION:FS impairment was noted in antipsychotic naïve/free SCZ, and it worsened with the introduction of distractors. An inversed laterality effect (rightward-bias) of distractor was noted in SCZ and their FDRs, suggesting a possible association of attenuation/reversal of visual functional asymmetry with SCZ vulnerability. Future studies should evaluate FS as illness markers across different clinical stages.

Objective: Obsessive-Compulsive Disorder (OCD) is characterized by abnormalities in the cortico-striato-thalamocortical (CSTC) circuitry of the brain. Antisaccade eye movement tasks measure aspects of the voluntary control of behaviour that are sensitive to CSTC circuitry dysfunction. Method: In this study, we examined antisaccade eye movement parameters of OCD patients in comparison with healthy controls (HC). In addition, we also examined the relationship between the antisaccade eye movement parameters and the severity of OCD. Antisaccade performance among right handed OCD patients (N = 65) was compared to matched right handed HC (N = 57). Eye tracking data during the task performance were collected using an Eye-Link eye-tracker at 1000-Hz sampling rate. OCD symptom severity was evaluated using Yale-Brown obsessive compulsive scale. Results: The antisaccade error percentage was significantly greater in OCD patients than HC (p < 0.001). In addition, OCD patients had less accurate final eye position compared to HC (p < 0.001). There were no significant correlation between antisaccade parameters and OCD severity measures. Conclusion: Deficient performance in antisaccade task supports CSTC abnormality in OCD and this appears to be independent of the illness severity. Examining this in remitted participants with OCD and in unaffected first degree relatives could help ascertaining their endophenotype validity.

Objectives Sensorimotor difficulties are often reported in autism spectrum disorders (ASD). Visual and motor skills are linked in that the processing of visual information can help in guiding motor movements. The present study investigated oculomotor skill and its relation to general motor skill in ASD by providing a comprehensive assessment of oculomotor control. Methods Fifty children (25 ASD; 25 typically developing [TD]), aged 7–10 years, completed a motor assessment (comprising fine and gross motor tasks) and oculomotor battery (comprising fixation, smooth pursuit, prosaccade and antisaccade tasks). Results No group differences were found for antisaccade errors, nor saccade latencies in prosaccade and antisaccade tasks, but increased saccade amplitude variability was observed in children with ASD, suggesting a reduced consistency in saccade accuracy. Children with ASD also demonstrated poorer fixation stability than their peers and spent less time in pursuit of a moving target. Motor skill was not correlated with saccade amplitude variability. However, regression analyses revealed that motor skill (and not diagnosis) accounted for variance in fixation performance and fast smooth pursuit. Conclusions The findings highlight the importance of considering oculomotor paradigms to inform the functional impact of neuropathologies in ASD and also assessing the presentation of co-occurring difficulties to further our understanding of ASD. Avenues for future research are suggested.

In this study we investigated effects of the APOE ε4 allele (which confers an enhanced risk of poorer cognitive ageing, and Alzheimer's Disease) on sustained attention (vigilance) performance in young adults using the Rapid Visual Information Processing (RVIP) task and event-related fMRI. Previous fMRI work with this task has used block designs: this study is the first to image an extended (6-minute) RVIP task. Participants were 26 carriers of the APOE ε4 allele, and 26 non carriers (aged 18-28). Pupil diameter was measured throughout, as an index of cognitive effort. We compared activity to RVIP task hits to hits on a control task (with similar visual parameters and response requirements but no working memory load): this contrast showed activity in medial frontal, inferior and superior parietal, temporal and visual cortices, consistent with previous work, demonstrating that meaningful neural data can be extracted from the RVIP task over an extended interval and using an event-related design. Behavioural performance was not affected by genotype; however, a genotype by condition (experimental task/control task) interaction on pupil diameter suggested that ε4 carriers deployed more effort to the experimental compared to the control task. fMRI results showed a condition by genotype interaction in the right hippocampal formation: only ε4 carriers showed downregulation of this region to experimental task hits versus control task hits. Experimental task beta values were correlated against hit rate: parietal correlations were seen in ε4 carriers only, frontal correlations in non-carriers only. The data indicate that, in the absence of behavioural differences, young adult ε4 carriers already show a different linkage between functional brain activity and behaviour, as well as aberrant hippocampal recruitment patterns. This may have relevance for genotype differences in cognitive ageing trajectories.

Introduction The APOE e4 allele has been linked to poorer cognitive aging and enhanced dementia risk. Previous imaging studies have used subsequent memory paradigms to probe hippocampal function in e4 carriers across the age range, and evidence suggests a pattern of hippocampal overactivation in young adult e4 carriers. Methods In this study, we employed a word-based subsequent memory task under fMRI; pupillometry data were also acquired as an index of cognitive effort. Participants (26 non-e4 carriers and 28 e4 carriers) performed an incidental encoding task (presented as word categorization), followed by a surprise old/new recognition task after a 40 minute delay. Results In e4 carriers only, subsequently remembered words were linked to increased hippocampal activity. Across all participants, increased pupil diameter differentiated subsequently remembered from forgotten words, and neural activity covaried with pupil diameter in cuneus and precuneus. These effects were weaker in e4 carriers, and e4 carriers did not show greater pupil diameter to remembered words. In the recognition phase, genotype status also modulated hippocampal activity: here, however, e4 carriers failed to show the conventional pattern of greater hippocampal activity to novel words. Conclusions Overall, neural activity changes were unstable in e4 carriers, failed to respond to novelty, and did not link strongly to cognitive effort, as indexed by pupil diameter. This provides further evidence of abnormal hippocampal recruitment in young adult e4 carriers, manifesting as both up and downregulation of neural activity, in the absence of behavioral performance differences.

Some aspects of saccadic performance have been found to be abnormal in chronic schizophrenia. The majority of this research has, however, been performed on patients treated with long-term antipsychotic medication. Very few studies have examined saccadic performance in antipsychotic-naïve/free patients. There are also very few studies describing the relationship between saccadic performance and clinical symptoms, particularly in antipsychotic free patients. In this study, we compared pro and antisaccade performance in a large sample of antipsychotic-naïve/free schizophrenia patients (N = 45) with healthy controls (N = 57). Clinical symptoms were assessed using Scale for Assessment of Positive Symptoms (SAPS) and Negative Symptoms (SANS). In the antisaccade task, patients made significantly more errors, and their correct antisaccades had smaller amplitudes in comparison to healthy controls. Higher error rates were associated with increased severity of hallucinations. In the prosaccade task, patients had less accurate final eye positions, and made saccades with slower latency and reduced amplitude compared to the healthy controls. These observations in schizophrenia patients without the potential confounds of antipsychotic treatment suggest intrinsic link between saccadic deficits and schizophrenia pathogenesis. The relationship between antisaccade errors and hallucination severity supports the potential link between hallucinations and deficits in inhibitory control.

Abstract Children with Developmental Coordination Disorder (DCD) fail to acquire adequate motor skill, yet surprisingly little is known about the oculomotor system in DCD. Successful completion of motor tasks is supported by accurate visual feedback. The purpose of this study was to determine whether any oculomotor differences can distinguish between children with and without a motor impairment. Using eye tracking technology, visual fixation, smooth pursuit, and pro‐ and anti‐saccade performance were assessed in 77 children that formed three groups: children with DCD (aged 7–10), chronologically age (CA) matched peers, and a motor‐match (MM) group (aged 4–7). Pursuit gain and response preparation in the pro‐ and anti‐saccade tasks were comparable across groups. Compared to age controls, children with DCD had deficits in maintaining engagement in the fixation and pursuit tasks, and made more anti‐saccade errors. The two typically developing groups performed similarly, except on the fast speed smooth pursuit and antisaccade tasks, where the CA group outperformed the younger MM group. The findings suggest that children with DCD have problems with saccadic inhibition and maintaining attention on a visual target. Developmental patterns were evident in the typically developing groups, suggesting that the pursuit system and cognitive control develop with age. This study adds to the literature by being the first to systematically identify specific oculomotor differences between children with and without a motor impairment. Further examination of oculomotor control may help to identify underlying processes contributing to DCD. A video abstract of this article can be viewed at: https://youtu.be/NinXa2KlB4M. [Correction added on 27 January 2017, after first online publication: The video abstract link was added.]

Healthy individuals with high as compared to low levels of schizotypal personality traits make more first saccades to the left side of faces, suggesting increased right hemisphere (RH) dominance for face processing. Patients with schizophrenia, however, show attenuated or reversed RH dominance for face processing. It is unclear whether the increased RH dominance found in high schizotypes is specific to face processing or whether it is also observable for other stimuli matched in terms of low-level visual properties. We measured gaze to faces and symmetrical fractal patterns and found higher Magical Ideation (MI) is associated with an increased left-side bias for initial saccade landing points and dwell times when free-viewing faces. These laterality biases were unaffected by facial emotion. Schizotypy scores were not related to laterality biases when viewing fractals. Our results provide further evidence that high schizotypy is associated with an increase in RH dominance for face processing.

Introduction. Individuals with schizophrenia frequently report disturbances in time perception, but the precise nature of such deficits and their relation to specific symptoms of the disorder is unclear. We sought to determine the relationship between hallucination proneness and time perception in healthy individuals, and whether this relationship is moderated by hypervigilance to threat-related stimuli. Methods. 206 participants completed the Revised Launay-Slade Hallucination Scale (LSHS-R) and a time reproduction task in which, on each trial, participants viewed a face (happy, angry, neutral, or fearful) for between 1 and 5 s and then reproduced the time period with a spacebar press. Results. High LSHS-R scores were associated with longer time estimates, but only during exposure to angry faces. A factor analysis of LSHS-R scores identified a factor comprising items related to reality monitoring, and this factor was most associated with the longer time estimates. Conclusions. During exposure to potential threat in the environment, duration estimates increase with hallucination proneness. The experience of feeling exposed to threat for longer may serve to maintain a state of hypervigilance which has been shown previously to be associated with positive symptoms of schizophrenia.

Across three experiments we sought to determine whether extrafoveally presented emotional faces are processed sufficiently rapidly to influence saccade programming. Two rectangular targets containing a neutral and an emotional face were presented either side of a central fixation cross. Participants made prosaccades towards an abrupt luminosity change to the border of one of the rectangles. The faces appeared 150 ms before or simultaneously with the cue. Saccades were faster towards cued rectangles containing emotional compared to neutral faces even when the rectangles were positioned 12 degrees from the fixation cross. When faces were inverted, the facilitative effect of emotion only emerged in the −150 ms SOA condition, possibly reflecting a shift from configural to featural face processing. Together the results suggest that the human brain is highly specialized for processing emotional information and responds very rapidly to the brief presentation of expressive faces, even when these are located outside foveal vision.

It has been suggested that certain types of auditory hallucinations may be the by-product of a perceptual system that has evolved to be oversensitive to threat-related stimuli. People with schizophrenia and high schizotypes experience visual as well as auditory hallucinations, and have deficits in processing facial emotions. We sought to determine the relationship between visual hallucination proneness and the tendency to misattribute threat and non-threat related emotions to neutral faces. Participants completed a questionnaire assessing visual hallucination proneness (the Revised Visual Hallucination Scale – RVHS). High scoring individuals (N=64) were compared to low scoring individuals (N=72) on a novel emotion detection task. The high RVHS group made more false positive errors (ascribing emotions to neutral faces) than the low RVHS group, particularly when detecting threat-related emotions. All participants made more false positives when neutral faces were presented to the right visual field than to the left visual field. Our results support continuum models of visual hallucinatory experience in which tolerance for false positives is highest for potentially threatening emotional stimuli and suggest that lateral asymmetries in face processing extend to the misperception of facial emotion.

Individuals reporting high levels of distractibility in everyday life show impaired performance in standard laboratory tasks measuring selective attention and inhibitory processes. Similarly, increasing cognitive load leads to more errors/distraction in a variety of cognitive tasks. How these two factors interact is currently unclear; highly distractible individuals may be affected more when their cognitive resources are taxed, or load may linearly affect performance for all individuals. We investigated the relationship between self-reported levels of cognitive failures (CF) in daily life and performance in the antisaccade task, a widely used tool examining attentional control. Levels of concurrent cognitive demand were manipulated using a secondary auditory discrimination task. We found that both levels of self-reported CF and task load increased antisaccade latencies while having no effect on prosaccade eye-movements. However individuals rating themselves as suffering few daily life distractions showed a comparable load cost to those who experience many. These findings suggest that the likelihood of distraction is governed by the addition of both internal susceptibility and the external current load placed on working memory.

It is believed that our attentional systems are hard-wired to attend to threat; however, an alternative explanation is simply that attention is quickly drawn to the stimulus of most personal relevance in the environment. We used an eye tracker to monitor attention to threat stimuli (spiders) and to positive stimuli with no biological or evolutionary relevance (pictures from the television program Dr. Who) during a target search task. We found that distracter pictures from Dr. Who were fixated on more quickly and were allocated more attention in terms of overall dwell time than were pictures of spiders by participants who had a strong interest in Dr. Who. As such, allocation of attention was guided by the personal relevance of the images, rather than their threat content per se. The attentional system believed to have a causal role in anxiety disordersmay therefore be a general system that responds to stimulus relevance rather than being specific to threat; hence, non-evolutionary images, such as those from Dr Who, are allocated attention in a similar manner as are fear relevant, spider, images. For people with an interest in Dr.Who and a fear of spiders therefore, the Empress of Racnoss (a spider-like creature who features in the program) might be the ultimate attention-grabbing stimulus.

Pupils dilate to a greater extent when participants view old compared to new items during recognition memory tests. We report three experiments investigating the cognitive processes associated with this pupil old/new effect. Using a remember/know procedure, we found that the effect occurred for old items that were both remembered and known at recognition, although it was attenuated for known compared to remembered items. In Experiment 2, the pupil old/new effect was observed when items were presented acoustically, suggesting the effect does not depend on low-level visual processes. The pupil old/new effect was also greater for items encoded under deep compared to shallow orienting instructions, suggesting it may reflect the strength of the underlying memory trace. Finally, the pupil old/new effect was also found when participants falsely recognized items as being old. We propose that pupils respond to a strength-of-memory signal and suggest that pupillometry provides a useful technique for exploring the underlying mechanisms of recognition memory.