The antisaccade: a review of basic research and clinical studies

Visuospatial, oculomotor, and executive reading skills evolve in elementary school, and errors are significant: a topological RAN study

We investigate the development of visuospatial and oculomotor reading skills in a cohort of elementary school children. Employing a longitudinal methodology, the study applies the Topological serial digit Rapid Automated Naming (Top-RAN) battery, which evaluates visuospatial reading skills leveraging metrics addressing crowding, distractors, and voluntary attention orientation. The participant pool comprises 142 students (66 males, 76 females), including 46 non-native speakers (21 males, 25 females), representing a diverse range of ethnic backgrounds. The Top-RAN dataset encompasses performance, error, and self-correction metrics for each subtest and student, underscoring the significance of these factors in the process of reading acquisition. Analytical methods include dimensionality reduction, clustering, and classification algorithms, consolidated into a Python package to facilitate reproducible results. Our results indicate that visuospatial reading abilities vary according to the task and demonstrate a marked evolution over time, as seen in the progressive decrease in execution times, errors, and self-corrections. This pattern supports the hypothesis that the growth of oculomotor, attentional, and executive skills is primarily fostered by educational experiences and maturation. This investigation provides valuable insights into the dynamic nature of these skills during pivotal educational stages.

Borderline personality disorder and multidimensional impulsivity: The roles of positive and negative emotion dysregulation

BACKGROUND

Risky, self-destructive impulsivity and emotion dysregulation are core features of borderline personality disorder (BPD). Yet impulsivity is multidimensional and has rarely been comprehensively assessed in BPD. Impulsivity has been linked to negative emotion dysregulation, yet explorations of the role of positive emotion dysregulation have been neglected. The current study attempts to extend existing literature by identifying the pattern of associations of specific domains of impulsivity, using both self-report and behavioral measures in BPD, and the role of both negative and positive emotion dysregulation in this link.

METHODS

Adults with BPD (n = 48), subthreshold BPD (n = 37), and without BPD (n = 78) completed a diagnostic interview, self-report measures, and multiple behavioral tasks. We examined correlations between primary variables, then examined the role of negative and positive emotion dysregulation in the association between BPD and specific domains of impulsivity.

RESULTS

Negative emotion dysregulation accounted for the link between BPD and negative urgency, (lack of) premeditation, and (lack of) perseverance, while positive emotion dysregulation accounted for the relation between BPD and sensation seeking.

LIMITATIONS

Key limitations of this study include using a relatively homogeneous sample and using abbreviated versions of one behavioral task, among others discussed.

CONCLUSIONS

These findings locate the precise impulsivity impairments in BPD and highlight the differential roles of negative and positive emotion dysregulation. Understanding the impulsivity deficits associated with BPD will further explain the impulsive behaviors associated with this disorder, and the contexts in which they occur, which may streamline clinical treatments.

Endophenotype trait domains for advancing gene discovery in autism spectrum disorder

Autism spectrum disorder (ASD) is associated with a diverse range of etiological processes, including both genetic and non-genetic causes. For a plurality of individuals with ASD, it is likely that the primary causes involve multiple common inherited variants that individually account for only small levels of variation in phenotypic outcomes. This genetic landscape creates a major challenge for detecting small but important pathogenic effects associated with ASD. To address similar challenges, separate fields of medicine have identified endophenotypes, or discrete, quantitative traits that reflect genetic likelihood for a particular clinical condition and leveraged the study of these traits to map polygenic mechanisms and advance more personalized therapeutic strategies for complex diseases. Endophenotypes represent a distinct class of biomarkers useful for understanding genetic contributions to psychiatric and developmental disorders because they are embedded within the causal chain between genotype and clinical phenotype, and they are more proximal to the action of the gene(s) than behavioral traits. Despite their demonstrated power for guiding new understanding of complex genetic structures of clinical conditions, few endophenotypes associated with ASD have been identified and integrated into family genetic studies. In this review, we argue that advancing knowledge of the complex pathogenic processes that contribute to ASD can be accelerated by refocusing attention toward identifying endophenotypic traits reflective of inherited mechanisms. This pivot requires renewed emphasis on study designs with measurement of familial co-variation including infant sibling studies, family trio and quad designs, and analysis of monozygotic and dizygotic twin concordance for select trait dimensions. We also emphasize that clarification of endophenotypic traits necessarily will involve integration of transdiagnostic approaches as candidate traits likely reflect liability for multiple clinical conditions and often are agnostic to diagnostic boundaries. Multiple candidate endophenotypes associated with ASD likelihood are described, and we propose a new focus on the analysis of "endophenotype trait domains" (ETDs), or traits measured across multiple levels (e.g., molecular, cellular, neural system, neuropsychological) along the causal pathway from genes to behavior. To inform our central argument for research efforts toward ETD discovery, we first provide a brief review of the concept of endophenotypes and their application to psychiatry. Next, we highlight key criteria for determining the value of candidate endophenotypes, including unique considerations for the study of ASD. Descriptions of different study designs for assessing endophenotypes in ASD research then are offered, including analysis of how select patterns of results may help prioritize candidate traits in future research. We also present multiple candidate ETDs that collectively cover a breadth of clinical phenomena associated with ASD, including social, language/communication, cognitive control, and sensorimotor processes. These ETDs are described because they represent promising targets for gene discovery related to clinical autistic traits, and they serve as models for analysis of separate candidate domains that may inform understanding of inherited etiological processes associated with ASD as well as overlapping neurodevelopmental disorders.

Clinical Saccadometry: Establishing Evaluative Standards Using a Simplified Video Oculography Protocol in the Adult Population

BACKGROUND

 Saccadometry is an advanced ocular motor test battery that allows for the functional evaluation of the varied brain regions and circuits involved in the generation of fast, purposeful, and accurate saccadic eye movements. The test battery is composed of prosaccade (PS) and antisaccade (AS) tests that progressively increase cognitive demand. Existing saccadometry protocols qualitatively describe trends across the lifespan, but have not been widely adopted by clinicians.

PURPOSE

 The aims of this study are to design an efficient and simplified clinical saccadometry protocol using video oculography (VOG) equipment and establish associated evaluative standards across the lifespan.

STUDY SAMPLE

 Data were reported on 273 adults ages 18 to 69 years.

RESULTS

 Evaluative data on four measures: directional error rate (DE), latency (Lat), peak velocity (Vel), and accuracy (Acc) during PS and AS measurements were provided. Age-group differences were found in Lat (p < 0.01) and Vel (p = 0.04) during PS and age-group differences were found in DE (p = 0.04), Lat (p < 0.01) and Vel (p < 0.01) during AS. Gender differences were found in DE (p = 0.01) and Lat (p < 0.01) during AS.

CONCLUSIONS

 This study established a standardized and time-efficient protocol with evaluative standards for individuals ages 18 to 69 years old to enable the use of saccadometry as an objective measure in the clinic. Saccadometry allows clinicians to look beyond the traditional saccade test and evaluate complex oculomotor and cognitive functions that will better help clinicians differentiate between peripheral and central diagnoses.

Utilizing artificial intelligence-based eye tracking technology for screening ADHD symptoms in children

Objective

To explore the potential of using artificial intelligence (AI)-based eye tracking technology on a tablet for screening Attention-deficit/hyperactivity disorder (ADHD) symptoms in children.

Methods

We recruited 112 children diagnosed with ADHD (ADHD group; mean age: 9.40 ± 1.70 years old) and 325 typically developing children (TD group; mean age: 9.45 ± 1.59 years old). We designed a data-driven end-to-end convolutional neural network appearance-based model to predict eye gaze to permit eye-tracking under low resolution and sampling rates. The participants then completed the eye tracking task on a tablet, which consisted of a simple fixation task as well as 14 prosaccade (looking toward target) and 14 antisaccade (looking away from target) trials, measuring attention and inhibition, respectively.

Results

Two-way MANOVA analyses demonstrated that diagnosis and age had significant effects on performance on the fixation task [diagnosis: F(2, 432) = 8.231, ***p < 0.001; Wilks' Λ = 0.963; age: F(2, 432) = 3.999, *p < 0.019; Wilks' Λ = 0.982], prosaccade task [age: F(16, 418) = 3.847, ***p < 0.001; Wilks' Λ = 0.872], and antisaccade task [diagnosis: F(16, 418) = 1.738, *p = 0.038; Wilks' Λ = 0.938; age: F(16, 418) = 4.508, ***p < 0.001; Wilks' Λ = 0.853]. Correlational analyses revealed that participants with higher SNAP-IV score were more likely to have shorter fixation duration and more fixation intervals (r = -0.160, 95% CI [0.250, 0.067], ***p < 0.001), poorer scores on adjusted prosaccade accuracy, and poorer scores on antisaccade accuracy (Accuracy: r = -0.105, 95% CI [-0.197, -0.011], *p = 0.029; Adjusted accuracy: r = -0.108, 95% CI [-0.200, -0.015], *p = 0.024).

Conclusion

Our AI-based eye tracking technology implemented on a tablet could reliably discriminate eye movements of the TD group and the ADHD group, providing a potential solution for ADHD screening outside of clinical settings.

Looking away to see: The acquisition of a search habit away from the saccade direction

Growing evidence has shown that attention can be habit-like, unconsciously and persistently directed toward locations that have frequently contained search targets in the past. The attentional preference typically arises when the eye gaze aligns with the attended location. Here we tested whether this spatial alignment is necessary for the acquisition of a search habit. To divert eye movements away from an attended location, we used gaze-contingent eye tracking, restricting the visible portion of the screen to an area opposite to the current gaze. Participants searched for a T target amidst a circular array of L distractors. Unbeknownst to them, the target appeared more frequently in one screen quadrant. Despite fixating on a location diametrically opposite to the visible, attended region, participants acquired probability cuing, producing quicker responses when the target appeared in the high-probability quadrant. They also showed a speed advantage in the diagonal quadrant. The attentional preference for the high-probability quadrant persisted during a testing phase in which the target's location was unbiased, but only when participants continued to search with the restricted view. These results indicate that a search habit can be acquired even when participants are required to look away from the high-probability locations. The finding suggests that the learned search habit is not solely a result of oculomotor learning.

Microsaccade rate activity during the preparation of pro- and antisaccades

Microsaccades belong to the category of fixational micromovements and may be crucial for image stability on the retina. Eye movement paradigms typically require fixational control, but this does not eliminate all oculomotor activity. The antisaccade task requires a planned eye movement in the direction opposite of an onset, allowing separation of planning and execution. We build on previous studies of microsaccades in the antisaccade task using a combination of fixed and mixed pro- and antisaccade blocks. We hypothesized that microsaccade rates may be reduced prior to the execution of antisaccades as compared with regular saccades (prosaccades). In two experiments, we measured microsaccades in four conditions across three trial blocks: one block each of fixed prosaccade and antisaccade trials, and a mixed block where both saccade types were randomized. We anticipated that microsaccade rates would be higher prior to antisaccades than prosaccades due to the need to preemptively suppress reflexive saccades during antisaccade generation. In Experiment 1, with monocular eye tracking, there was an interaction between the effects of saccade and block type on microsaccade rates, suggesting lower rates on antisaccade trials, but only within mixed blocks. In Experiment 2, eye tracking was binocular, revealing suppressed microsaccade rates on antisaccade trials. A cluster permutation analysis of the microsaccade rate over the course of a trial did not reveal any particular critical time for this difference in microsaccade rates. Our findings suggest that microsaccade rates reflect the degree of suppression of the oculomotor system during the antisaccade task.

Spatial bias in anti-saccade endpoints following bilateral dorsal posterior parietal lesions

Anti-saccades are eye movements in which the saccade is executed in the opposite direction of a visual target and are often hypometric. Because the visual target and saccade goal are decoupled, it has been suggested that competition between the two locations occurs and needs to be resolved. It has been hypothesized that the hypometria of anti-saccades reflects this spatial competition by revealing a bias towards the visual target. To confirm that this hypometria is not simply due to reduced gain, we tested 10 healthy subjects on three different anti-saccade spatial configuration tasks: 90° away across hemifields, 90° away within the same hemifield and 180° away (classic, diagonally opposite). Specifically, we examined whether saccade endpoints showed evidence for the visual target location's interference with anti-saccade programming and execution processes. Among other neural substrates involved in anti-saccades production, the dorsal posterior parietal cortex (PPC) has been implicated in the spatial inhibition of contralateral visual target. To gain insight into the neural processes involved in spatial competition during anti-saccades, we also tested one patient with a bilateral dorsal PPC lesion. In all spatial configurations, we observed that anti-saccade endpoints demonstrated a spatial bias towards the visual target for all participants, likely due to an incomplete inhibition of the visual target location. This spatial bias was exacerbated in our patient, which suggests that the dorsal PPC contributes to the amalgamation of the two competing spatial representations.

Abnormal eye movement features in patients with depression: Preliminary findings based on eye tracking technology

BACKGROUND

Saccadic eye movement (SEM) has been considered a non-invasive potential biomarker for the diagnosis of depression in recent years, but its application is not yet mature. In this study, we used eye-tracking technology to identify the eye movements of patients with depression to develop a new method for objectively identifying depression.

METHODS

Thirty-six patients with depression as the depression group, while thirty-six matched healthy individuals as the control group were recruited and completed eye movement tests, including two tasks: the prosaccade task and the antisaccade task. iViewX RED 500 eye-tracking instruments from SMI were used to collect eye movement data for both groups.

RESULTS

In the prosaccade task, there was no difference between the depression and control groups(t = 0.019， P > 0.05). In general, with increasing angle, both groups showed significantly higher peak velocity (F = 81.72， P < 0.0001), higher mean velocity (F = 32.83, P = 0.000), and greater SEM amplitude (F = 24.23, P < 0.0001). In the antisaccade task, there were significant differences in correct rate (t = 3.219, P = 0.002) and mean velocity (F = 3.253， P < 0.05) between the depression group and the control group. In the anti-effect analysis, there were significant differences in correct rate (F = 67.44, P < 0.0001) and accuracy (F = 79.02, P < 0.0001) between the depression group and the control group. Both groups showed longer latency and worse correct rate and precision in the antisaccade task compared with the prosaccade task.

CONCLUSION

Patients with depression showed different eye movement features, which could be potential biomarkers for clinical identification. Further studies must validate these results with larger sample sizes and more clinical populations.

Look into my eyes: What can eye-based measures tell us about the relationship between physical activity and cognitive performance?

BACKGROUND

There is a growing interest to understand the neurobiological mechanisms that drive the positive associations of physical activity and fitness with measures of cognitive performance. To better understand those mechanisms, several studies have employed eye-based measures (e.g., eye movement measures such as saccades, pupillary measures such as pupil dilation, and vascular measures such as retinal vessel diameter) deemed to be proxies for specific neurobiological mechanisms. However, there is currently no systematic review providing a comprehensive overview of these studies in the field of exercise-cognition science. Thus, this review aimed to address that gap in the literature.

METHODS

To identify eligible studies, we searched 5 electronic databases on October 23, 2022. Two researchers independently extracted data and assessed the risk of bias using a modified version of the Tool for the assEssment of Study qualiTy and reporting in EXercise (TESTEX scale, for interventional studies) and the critical appraisal tool from the Joanna Briggs Institute (for cross-sectional studies).

RESULTS

Our systematic review (n = 35 studies) offers the following main findings: (a) there is insufficient evidence available to draw solid conclusions concerning gaze-fixation-based measures; (b) the evidence that pupillometric measures, which are a proxy for the noradrenergic system, can explain the positive effect of acute exercise and cardiorespiratory fitness on cognitive performance is mixed; (c) physical training- or fitness-related changes of the cerebrovascular system (operationalized via changes in retinal vasculature) are, in general, positively associated with cognitive performance improvements; (d) acute and chronic physical exercises show a positive effect based on an oculomotor-based measure of executive function (operationalized via antisaccade tasks); and (e) the positive association between cardiorespiratory fitness and cognitive performance is partly mediated by the dopaminergic system (operationalized via spontaneous eye-blink rate).

CONCLUSION

This systematic review offers confirmation that eye-based measures can provide valuable insight into the neurobiological mechanisms that may drive positive associations between physical activity and fitness and measures of cognitive performance. However, due to the limited number of studies utilizing specific methods for obtaining eye-based measures (e.g., pupillometry, retinal vessel analysis, spontaneous eye blink rate) or investigating a possible dose-response relationship, further research is necessary before more nuanced conclusions can be drawn. Given that eye-based measures are economical and non-invasive, we hope this review will foster the future application of eye-based measures in the field of exercise-cognition science.

Methylphenidate as a treatment option for substance use disorder: a transdiagnostic perspective

A transition in viewing mental disorders from conditions defined as a set of unique characteristics to one of the quantitative variations on a collection of dimensions allows overlap between disorders. The overlap can be utilized to extend to treatment approaches. Here, we consider the overlap between attention-deficit/hyperactivity disorder and substance use disorder to probe the suitability to use methylphenidate as a treatment for substance use disorder. Both disorders are characterized by maladaptive goal-directed behavior, impaired cognitive control, hyperactive phasic dopaminergic neurotransmission in the striatum, prefrontal hypoactivation, and reduced frontal cortex gray matter volume/density. In addition, methylphenidate has been shown to improve cognitive control and normalize associated brain activation in substance use disorder patients and clinical trials have found methylphenidate to improve clinical outcomes. Despite the theoretical basis and promising, but preliminary, outcomes, many questions remain unanswered. Most prominent is whether all patients who are addicted to different substances may equally profit from methylphenidate treatment.

Eye movements in patients with post-COVID condition

Eye movement control is impaired in some neurological conditions, but the impact of COVID-19 on eye movements remains unknown. This study aims to investigate differences in oculomotor function and pupil response in individuals who suffer post-COVID-19 condition (PCC) with cognitive deficits. Saccades, smooth pursuit, fixation, vergence and pupillary response were recorded using an eye tracker. Eye movements and pupil response parameters were computed. Data from 16 controls, 38 COVID mild (home recovery) and 19 COVID severe (hospital admission) participants were analyzed. Saccadic latencies were shorter in controls (183 ± 54 ms) than in COVID mild (236 ± 83 ms) and COVID severe (227 ± 42 ms) participants (p = 0.017). Fixation stability was poorer in COVID mild participants (Bivariate Contour Ellipse Area of 0.80 ± 1.61°2 vs 0.36 ± 0.65 °2 for controls, p = 0.019), while percentage of pupil area reduction/enlargement was reduced in COVID severe participants (39.7 ± 12.7%/31.6 ± 12.7% compared to 51.7 ± 22.0%/49.1 ± 20.7% in controls, p < 0.015). The characteristics of oculomotor alterations found in PCC may be useful to understand different pathophysiologic mechanisms.

Eye-tracking paradigms for the assessment of mild cognitive impairment: a systematic review

Mild cognitive impairment (MCI), representing the 'transitional zone' between normal cognition and dementia, has become a novel topic in clinical research. Although early detection is crucial, it remains logistically challenging at the same time. While traditional pen-and-paper tests require in-depth training to ensure standardized administration and accurate interpretation of findings, significant technological advancements are leading to the development of procedures for the early detection of Alzheimer's disease (AD) and facilitating the diagnostic process. Some of the diagnostic protocols, however, show significant limitations that hamper their widespread adoption. Concerns about the social and economic implications of the increasing incidence of AD underline the need for reliable, non-invasive, cost-effective, and timely cognitive scoring methodologies. For instance, modern clinical studies report significant oculomotor impairments among patients with MCI, who perform poorly in visual paired-comparison tasks by ascribing less attentional resources to novel stimuli. To accelerate the Global Action Plan on the Public Health Response to Dementia 2017-2025, this work provides an overview of research on saccadic and exploratory eye-movement deficits among older adults with MCI. The review protocol was drafted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Electronic databases were systematically searched to identify peer-reviewed articles published between 2017 and 2022 that examined visual processing in older adults with MCI and reported gaze parameters as potential biomarkers. Moreover, following the contemporary trend for remote healthcare technologies, we reviewed studies that implemented non-commercial eye-tracking instrumentation in order to detect information processing impairments among the MCI population. Based on the gathered literature, eye-tracking-based paradigms may ameliorate the screening limitations of traditional cognitive assessments and contribute to early AD detection. However, in order to translate the findings pertaining to abnormal gaze behavior into clinical applications, it is imperative to conduct longitudinal investigations in both laboratory-based and ecologically valid settings.

Stimulus salience conflicts and colludes with endogenous goals during urgent choices

Selecting where to look next depends on both the salience of objects and current goals (what we are looking for), but discerning their relative contributions over the time frame of typical visuomotor decisions (200-250 ms) has been difficult. Here we investigate this problem using an urgent choice task with which the two contributions can be dissociated and tracked moment by moment. Behavioral data from three monkeys corresponded with model-based predictions: when salience favored the target, perceptual performance evolved rapidly and steadily toward an asymptotic level; when salience favored the distracter, many rapid errors were produced and the rise in performance took more time-effects analogous to oculomotor and attentional capture. The results show that salience has a brief (∼50 ms) but inexorable impact that leads to exogenous, involuntary capture, and this can either help or hinder performance, depending on the alignment between salience and ongoing internal goals.

Machine Learning and Eye Movements Give Insights into Neurodegenerative Disease Mechanisms

Humans are a vision-dominated species; what we perceive depends on where we look. Therefore, eye movements (EMs) are essential to our interactions with the environment, and experimental findings show EMs are affected in neurodegenerative disorders (ND). This could be a reason for some cognitive and movement disorders in ND. Therefore, we aim to establish whether changes in EM-evoked responses can tell us about the progression of ND, such as Alzheimer's (AD) and Parkinson's diseases (PD), in different stages. In the present review, we have analyzed the results of psychological, neurological, and EM (saccades, antisaccades, pursuit) tests to predict disease progression with machine learning (ML) methods. Thanks to ML algorithms, from the high-dimensional parameter space, we were able to find significant EM changes related to ND symptoms that gave us insights into ND mechanisms. The predictive algorithms described use various approaches, including granular computing, Naive Bayes, Decision Trees/Tables, logistic regression, C-/Linear SVC, KNC, and Random Forest. We demonstrated that EM is a robust biomarker for assessing symptom progression in PD and AD. There are navigation problems in 3D space in both diseases. Consequently, we investigated EM experiments in the virtual space and how they may help find neurodegeneration-related brain changes, e.g., related to place or/and orientation problems. In conclusion, EM parameters with clinical symptoms are powerful precision instruments that, in addition to their potential for predictions of ND progression with the help of ML, could be used to indicate the different preclinical stages of both diseases.

Physically active undergraduates perform better on executive-related oculomotor control: Evidence from the antisaccade task and pupillometry

Previous studies have shown that exercise can improve executive function in young and older adults. However, it remains controversial whether a sufficient amount of physical activity leads to higher-level executive function. To examine the effect of physical activity on executive function, we used eye-tracking technology and the antisaccade task in 41 young undergraduates with various levels of physical activity. Moreover, we also investigated their differences in cognitive ability by examining their pupil size during the antisaccade task. Eye-tracking results showed that physically active individuals showed shorter saccade latency and higher accuracy in the antisaccade task than their physically inactive counterparts. Furthermore, the former showed larger pupil size during the preparatory period of antisaccade. These findings suggest that individuals with higher-level physical activity have higher-level executive function. The larger pupil sizes of physically active individuals may imply that their locus coeruleus-norepinephrine system and executive-related prefrontal cortex are more active, which contributes to their higher-level cognitive ability.

The effect of visual target presence and age on antisaccade performance

Antisaccade and prosaccade (PS) performance were studied in a large cohort of females (age range 42-74 yr). Antisaccade performance was assessed in two variants of the task, a "traditional" antisaccade (TA) task, in which no visual stimuli were present at the saccade goal, and a visually guided antisaccade (VGA) task, in which small visual stimuli were present at the possible saccade goals prior to the imperative visual stimulus. Directional error frequency was similar in the two antisaccade tasks. However, reaction time (RT) was ∼33 ms longer in the VGA task than in the TA task. Across participants, the average saccade amplitudes of prosaccades and TAs were both correlated with those of VGAs but not with each other. TAs had a hypermetria that increased with age. Saccade amplitude variability was much higher for TAs than for PSs and VGAs. Saccade polar angle variability was low for all three tasks. Age diminished performance with modest task dependence, except for an increase in TA hypermetria. These results suggest that the generation of antisaccade directional errors does not depend on visual target presence at the saccade goal, that antisaccade RT can be affected by target presence, that age can increase saccade hypermetria in the absence of visual guidance, and that visually guided antisaccades are governed by distinct voluntary and visually guided saccade mechanisms. Moreover, these results suggest that an understanding of human motor performance benefits from the use of a participant pool with a larger age range than that used in most studies.NEW & NOTEWORTHY This study uses a visually guided antisaccade (VGA) task to determine whether poor performance in a large middle-aged participant pool on an antisaccade task results from problems with executive control or voluntary saccade generation. Spatial and temporal attributes of saccade performance as a function of task and age are analyzed comprehensively. Correlational analysis is used to determine how VGAs are governed jointly by voluntary and visually guided movement mechanisms.

Stimulation of non-motor subthalamic nucleus impairs selective response inhibition via prefrontal connectivity

Given the inconsistent results in the past, there is an ongoing debate whether and how deep brain stimulation in the subthalamic nucleus modifies cognitive control processes like response inhibition in persons with Parkinson's disease. In this study, we examined how the location of the stimulation volume within the subthalamic nucleus affects the performance in an antisaccade task but also how its structural connectivity is related to response inhibition. Antisaccade error rates and latencies were collected in 14 participants on and off deep brain stimulation in a randomized order. Stimulation volumes were computed based on patient-specific lead localizations using preoperative MRI and postoperative CT scans. Structural connectivity of the stimulation volumes with pre-defined cortical oculomotor control regions as well as whole-brain connectivity was estimated using a normative connectome. We showed that the detrimental effect of deep brain stimulation on response inhibition, measured as antisaccade error rate, depended upon the magnitude of the intersection of volumes of activated tissue with the non-motor subregion of the subthalamic nucleus and on its structural connectivity with regions of the prefrontal oculomotor network including bilateral frontal eye fields and right anterior cingulate cortex. Our results corroborate previous recommendations for avoidance of stimulation in the ventromedial non-motor subregion of the subthalamic nucleus which connects to the prefrontal cortex to prevent stimulation-induced impulsivity. Furthermore, antisaccades were initiated faster with deep brain stimulation when the stimulation volume was connected to fibres passing the subthalamic nucleus laterally and projecting onto the prefrontal cortex, indicating that improvement of voluntary saccade generation with deep brain stimulation may be an off-target effect driven by stimulation of corticotectal fibres directly projecting from the frontal and supplementary eye fields onto brainstem gaze control areas. Taken together, these findings could help implement individualized circuit-based deep brain stimulation strategies that avoid impulsive side effects while improving voluntary oculomotor control.

Executive Function Poststroke: Concepts, Recovery, and Interventions

Executive function is frequently impaired among people who have sustained stroke. This review provides an overview of definitions, concepts, and measures. The review also summarizes current best evidence examining executive function impairment and recovery trajectories after stroke, correlates of change over time, and emerging intervention research. Finally, this review provides recommendations for research and clinical practices, as well as priorities for future executive function research.

Cortical-subcortical interactions in goal-directed behavior

Flexibly selecting appropriate actions in response to complex, ever-changing environments requires both cortical and subcortical regions, which are typically described as participating in a strict hierarchy. In this traditional view, highly specialized subcortical circuits allow for efficient responses to salient stimuli, at the cost of adaptability and context specificity, which are attributed to the neocortex. Their interactions are often described as the cortex providing top-down command signals for subcortical structures to implement; however, as available technologies develop, studies increasingly demonstrate that behavior is represented by brainwide activity and that even subcortical structures contain early signals of choice, suggesting that behavioral functions emerge as a result of different regions interacting as truly collaborative networks. In this review, we discuss the field's evolving understanding of how cortical and subcortical regions in placental mammals interact cooperatively, not only via top-down cortical-subcortical inputs but through bottom-up interactions, especially via the thalamus. We describe our current understanding of the circuitry of both the cortex and two exemplar subcortical structures, the superior colliculus and striatum, to identify which information is prioritized by which regions. We then describe the functional circuits these regions form with one another, and the thalamus, to create parallel loops and complex networks for brainwide information flow. Finally, we challenge the classic view that functional modules are contained within specific brain regions; instead, we propose that certain regions prioritize specific types of information over others, but the subnetworks they form, defined by their anatomical connections and functional dynamics, are the basis of true specialization.

Inhibitory Control in Male and Female Adolescents with Autism Spectrum Disorder (ASD)

The present study examined potential sex- and age-related differences in inhibitory control in adolescents with and without ASD. A computerized flanker visual filtering task and a go/no-go task were used to assess the ability to resist interference from visual distractors (RIVD) and prepotent response inhibition, respectively. Overall, the ASD and non-ASD groups performed comparably on both tasks and no sex-related differences or interactions (group-by-sex) were apparent. Consistent with past research, however, we did observe a significant age-related improvement in RIVD performance among the ASD group (but not the non-ASD group).

Electrophysiological responses to emotional and cocaine cues reveal individual neuroaffective profiles in cocaine users

Smokers with stronger neuroaffective responses to drug-related cues compared to nondrug-related pleasant images (C > P) are more vulnerable to compulsive smoking than individuals with the opposite brain reactivity profile (P > C). However, it is unknown if these neurobehavioral profiles exist in individuals abusing other drugs. We tested whether individuals with cocaine use disorder (CUD) show similar neuroaffective profiles to smokers. We also monitored eye movements to assess attentional bias toward cues and we further performed exploratory analyses on demographics, personality, and drug use between profiles. Participants with CUD (n = 43) viewed pleasant, unpleasant, cocaine, and neutral images while we recorded electroencephalogram. For each picture category, we computed the amplitude of the late positive potential (LPP), an event-related potential component that reflects motivational relevance. k-means clustering classified participants based on their LPP responses. In line with what has been observed in smokers, clustering participants using LPP responses revealed the presence of two groups: one with larger LPPs to pleasant images compared to cocaine images (P > C) and one group with larger LPPs to cocaine images compared to pleasant images (C > P). Individuals with the C > P reactivity profile also had higher attentional bias toward drug cues. The two groups did not differ on demographic and drug use characteristics, however individuals with the C > P profile reported lower distress tolerance, higher anhedonia, and higher posttraumatic stress symptoms compared to the P > C group. This is the first study to report the presence of these neuroaffective profiles in individuals with CUD, indicating that this pattern may cut across addiction populations. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Reduced task-evoked pupillary response in preparation for an executive cognitive control response among individuals across the psychosis spectrum

Task-evoked pupillary response (TEPR) is a measure of physiological arousal modulated by cognitive demand. Healthy individuals demonstrate greater TEPR prior to correct versus error antisaccade trials and correct antisaccade versus visually guided saccade (VGS) trials. The relationship between TEPR and antisaccade performance in individuals with psychotic disorders and their relatives has not been investigated. Probands with schizophrenia, schizoaffective disorder, psychotic bipolar disorder, their first-degree relatives, and controls from the B-SNIP study completed antisaccade and VGS tasks. TEPR prior to execution of responses on these tasks was evaluated among controls compared to probands and relatives according to diagnostic groups and neurobiologically defined subgroups (biotypes). Controls demonstrated greater TEPR on antisaccade correct versus error versus VGS trials. TEPR was not differentiated between antisaccade correct versus error trials in bipolar or schizophrenia probands, though was greater on antisaccade compared to prosaccade trials. There was no modulation of TEPR in schizoaffective probands. Relatives of schizophrenia and schizoaffective probands and those with elevated psychosis spectrum traits failed to demonstrate differential TEPR on antisaccade correct versus error trials. No proband or relative biotypes demonstrated differential TEPR on antisaccade correct versus error trials, and only proband biotype 3 and relative biotypes 3 and 2 demonstrated greater TEPR on antisaccade versus VGS trials. Our findings suggest that aberrant modulation of preparatory activity prior to saccade execution contributes to impaired executive cognitive control across the psychosis spectrum, including nonpsychotic relatives with elevated clinical risk. Reduced pupillary modulation under cognitive challenge may thus be a biomarker for the psychosis phenotype.

Structural and functional MRI evidence for significant contribution of precentral gyrus to flexible oculomotor control: evidence from the antisaccade task

Antisaccade task requires inhibition of a prepotent prosaccade to a peripheral target and initiation of a saccade to the opposite location, and, therefore, is used as a tool to investigate behavioral adjustment. The frontal and parietal cortices are both known for their activation during saccade generation, but it is unclear whether their neuroanatomical characteristics also contribute to antisaccades. Here, we took antisaccade cost (antisaccade latency minus prosaccade latency) as an index for additional time for generating antisaccades. Fifty-eight participants conducted pro and antisaccade tasks outside the magnetic resonance imaging (MRI) scanner and their structural MRI (sMRI) data were also collected to explore brain regions neuroanatomically related to antisaccade cost. Then, twelve participants performed saccade tasks in the scanner and their task-state functional MRI (fMRI) data were collected to verify the activation of structurally identified brain regions during the saccade generation. Voxel-based morphometry (VBM) results revealed that gray matter volume (GMV) of the left precentral gyrus and the left insula were positively correlated with the antisaccade cost, which was validated by the prediction analysis. Brain activation results showed the activation of the precentral during both pro and antisaccade execution period, but not the insula. Our results suggest that precentral gyrus and insula play vital roles to antisaccade cost, but possibly in different ways. The insula, a key node of the salience network, possibly regulates the saliency processing of the target, while the precentral gyrus possibly mediates the generation of saccades. Our study especially highlights an outstanding role of the precentral gyrus in flexible oculomotor control.

Assessing the attentional bias of smokers in a virtual reality anti-saccade task using eye tracking

INTRODUCTION

Cognitive biases (among them attentional bias, AB) are considered an important factor in the development, maintenance, and recurrence of addiction. However, traditional paradigms to measure AB have been criticized regarding external validity and methodical issues. Therefore, and because the neurophysiological correlates of anti-saccade tasks are known, we implemented a novel smoking anti-saccade task in virtual reality (VR) to measure AB and inhibitory control in different contexts and with higher ecological validity.

METHODS

Smokers (n = 20) and non-smokers (n = 20) were tested on a classic pro- and anti-saccade task, a VR anti-saccade task and a VR attention fixation task (all containing smoking-related and neutral stimuli) while eye-tracking data was collected. Two VR contexts (park and office room) were applied.

RESULTS

Saccade latencies were significantly higher for the smoking group in the VR anti-saccade task. However, this effect did not differ between smoking-related and neutral stimuli, thus overall no AB was observed. Instead, AB was only present in the park context. Additionally, saccade latencies and error rates were significantly higher in the park context.

CONCLUSIONS

Results indicate impaired inhibitory control in smokers relative to non-smokers. The lack of evidence for a general AB might be due to the lower severity of smoking dependence in the smoking sample. Instead, results suggest context specificity of AB. Implications for smoking cessation interventions in the field of inhibitory control training and attention bias modification are discussed.

Does cognitive reflection predict attentional control in visual tasks?

The cognitive reflection test (CRT) measures the ability to suppress an intuitive, but incorrect, answer that easily comes to mind. The relationship between the CRT and different cognitive biases has been widely studied. However, whether cognitive reflection is related to attentional control is less well studied. The aim of this paper is to investigate whether the inhibitory component of the CRT, measured by the number of non-intuitive answers of the CRT (Inhibitory Control Score), is related to the control of visual attention in visual tasks that involve overriding a bias in what to attend: an anti-saccade task and a visual search task. To test this possibility, we analyzed whether the CRT-Inhibitory Control Score (CRT-ICS) predicted attention allocation in each task. We compared the relationship between the CRT-ICS to two other potential predictors of attentional control: numeracy and visual working memory (VWM). Participants who scored lower on the CRT-ICS made more errors in the "look-away" trials in the anti-saccade task. Participants who scored higher on the CRT-ICS looked more often towards more informative color subsets in the visual search task. However, when controlling for numeracy and visual working memory, CRT-ICS scores were only related to the control of visual attention in the anti-saccade task.

Purkinje Cell Activity in the Medial and Lateral Cerebellum During Suppression of Voluntary Eye Movements in Rhesus Macaques

Volitional suppression of responses to distracting external stimuli enables us to achieve our goals. This volitional inhibition of a specific behavior is supposed to be mainly mediated by the cerebral cortex. However, recent evidence supports the involvement of the cerebellum in this process. It is currently not known whether different parts of the cerebellar cortex play differential or synergistic roles in the planning and execution of this behavior. Here, we measured Purkinje cell (PC) responses in the medial and lateral cerebellum in two rhesus macaques during pro- and anti-saccade tasks. During an antisaccade trial, non-human primates (NHPs) were instructed to make a saccadic eye movement away from a target, rather than toward it, as in prosaccade trials. Our data show that the cerebellum plays an important role not only during the execution of the saccades but also during the volitional inhibition of eye movements toward the target. Simple spike (SS) modulation during the instruction and execution periods of pro- and anti-saccades was prominent in PCs of both the medial and lateral cerebellum. However, only the SS activity in the lateral cerebellar cortex contained information about stimulus identity and showed a strong reciprocal interaction with complex spikes (CSs). Moreover, the SS activity of different PC groups modulated bidirectionally in both of regions, but the PCs that showed facilitating and suppressive activity were predominantly associated with instruction and execution, respectively. These findings show that different cerebellar regions and PC groups contribute to goal-directed behavior and volitional inhibition, but with different propensities, highlighting the rich repertoire of the cerebellar control in executive functions.

Making a saccade enhances Stroop and Simon conflict control

Cognitive control is an important ability instantiated in many situations such as conflict control (e.g., Stroop/Simon task) and the control of eye movements (e.g., saccades). However, it is unclear whether eye movement control shares a common cognitive control system with the conflict control. In Experiment 1, we asked participants to make a prosaccade or antisaccade and then to identify the color of a lateralized color word (i.e., a Stroop-Simon stimulus). The stimulus onset asynchrony (SOA) between the saccadic cue and the Stroop-Simon stimulus was manipulated to be either short (200 ms) or long (600 ms). Results showed that the Stroop effect at the response level and the (negative) Simon effect were smaller when the SOA was short than long, demonstrating a decline of response control over time after making a saccade. Moreover, this temporal change of the Simon effect was more pronounced in the antisaccade session than in the prosaccade session. Furthermore, individuals who had better performance in the antisaccade task performed better in the response control of Stroop interference. When the saccade task was removed in Experiment 2, the temporal declines of the response control observed in Experiment 1 were absent. Experiment 3 replicated the key results of Experiment 1 by replacing the Stroop-Simon task with a typical Simon task and separately testing the typical Stroop and Simon tasks. Overall, our findings suggest that a common system is shared between the control of eye movements and the conflict control at the response level.

Applying machine learning to dissociate between stroke patients and healthy controls using eye movement features obtained from a virtual reality task

Conventional neuropsychological tests do not represent the complex and dynamic situations encountered in daily life. Immersive virtual reality simulations can be used to simulate dynamic and interactive situations in a controlled setting. Adding eye tracking to such simulations may provide highly detailed outcome measures, and has great potential for neuropsychological assessment. Here, participants (83 stroke patients and 103 healthy controls) we instructed to find either 3 or 7 items from a shopping list in a virtual super market environment while eye movements were being recorded. Using Logistic Regression and Support Vector Machine models, we aimed to predict the task of the participant and whether they belonged to the stroke or the control group. With a limited number of eye movement features, our models achieved an average Area Under the Curve (AUC) of .76 in predicting whether each participant was assigned a short or long shopping list (3 or 7 items). Identifying participant as either stroke patients and controls led to an AUC of .64. In both classification tasks, the frequency with which aisles were revisited was the most dissociating feature. As such, eye movement data obtained from a virtual reality simulation contain a rich set of signatures for detecting cognitive deficits, opening the door to potential clinical applications.

Anti-saccade as a Tool to Evaluate Neurocognitive Impairment in Alcohol Use Disorder

It has been widely shown that chronic alcohol use leads to cognitive dysfunctions, especially inhibitory control. In an extension of the traditional approach, this research field has benefited from the emergence of innovative measures, among which is an anti-saccade, allowing direct and sensitive measure of the eye movements indexing attention bias to alcohol-related cues and the capability of inhibiting the reflexive saccades to the cues. During the past decade, there are numerous reports showing that drinkers make more unwanted reflexive saccades and longer latency in the anti-saccade task. These increased errors are usually explained by the deficits in inhibitory control. It has been demonstrated that inhibitory control on eye movement may be one of the earliest biomarkers of the onset of alcohol-related cognitive impairments. This review summarizes how an anti-saccade task can be used as a tool to investigate and assess the cognitive dysfunctions and the early detection of relapsing risk of alcohol dependence.

Antisaccades in Parkinson's Disease: A Meta-Analysis

The usefulness of eye-tracking tasks as potential biomarkers for motor or cognitive disease burden in Parkinson's disease (PD) has been subject of debate for many years. Several studies suggest that the performance in the antisaccade task may be altered in patients with PD and associated with motor disease severity or executive dysfunction. In this meta-analysis, random effects models were used to synthesize the existing evidence on antisaccade error rates and latency in PD. Furthermore, meta-regressions were performed to assess the role of motor and cognitive disease severity, dopaminergic medication and methodological factors. Additionally, the impact of acute levodopa administration and activation of deep brain stimulation was evaluated in two separate sub-analyses.This meta-analysis confirms that antisaccade latency and error rate are significantly increased in PD. Disease duration, Unified Parkinson's disease rating scale score and Hoehn and Yahr stage mediate the effect of PD on antisaccade latency with higher motor burden being associated with increased antisaccade latency.Acute administration of levodopa had no significant effects on antisaccade performance in a small number of eligible studies. Deep brain stimulation in the subthalamic nucleus, on the other hand, may alter the speed accuracy trade-off supporting an increase of impulsivity following deep brain stimulation in PD.According to the results of the meta-analysis, antisaccade latency may provide a potential marker for disease severity and progression in PD which needs further confirmation in longitudinal studies.

Activated PI3Kδ syndrome, an immunodeficiency disorder, leads to sensorimotor deficits recapitulated in a murine model

The phosphoinositide-3-kinase (PI3K) family plays a major role in cell signaling and is predominant in leukocytes. Gain-of-function (GOF) mutations in the PIK3CD gene lead to the development of activated PI3Kδ syndrome (APDS), a rare primary immunodeficiency disorder. A subset of APDS patients also displays neurodevelopmental delay symptoms, suggesting a potential role of PIK3CD in cognitive and behavioural function. However, the extent and nature of the neurodevelopmental deficits has not been previously quantified. Here, we assessed the cognitive functions of two APDS patients, and investigated the causal role of the PIK3CD GOF mutation in neurological deficits using a murine model of this disease. We used p110δ^E1020K knock-in mice, harbouring the most common APDS mutation in patients. We found that APDS patients present with visuomotor deficits, exacerbated by autism spectrum disorder comorbidity, whereas p110δ^E1020K mice exhibited impairments in motor behaviour, learning and repetitive behaviour patterning. Our data indicate that PIK3CD GOF mutations increase the risk for neurodevelopmental deficits, supporting previous findings on the interplay between the nervous and the immune system. Further, our results validate the knock-in mouse model, and offer an objective assessment tool for patients that could be incorporated in diagnosis and in the evaluation of treatments.

The Potential of Naturalistic Eye Movement Tasks in the Diagnosis of Alzheimer's Disease: A Review

Extensive research has demonstrated that eye-tracking tasks can effectively indicate cognitive impairment. For example, lab-based eye-tracking tasks, such as the antisaccade task, have robustly distinguished between people with Alzheimer’s disease (AD) and healthy older adults. Due to the neurodegeneration associated with AD, people with AD often display extended saccade latencies and increased error rates on eye-tracking tasks. Although the effectiveness of using eye tracking to identify cognitive impairment appears promising, research considering the utility of eye tracking during naturalistic tasks, such as reading, in identifying cognitive impairment is limited. The current review identified 39 articles assessing eye-tracking distinctions between people with AD, mild cognitive impairment (MCI), and healthy controls when completing naturalistic task (reading, real-life simulations, static image search) or a goal-directed task involving naturalistic stimuli. The results revealed that naturalistic tasks show promising biomarkers and distinctions between healthy older adults and AD participants, and therefore show potential to be used for diagnostic and monitoring purposes. However, only twelve articles included MCI participants and assessed the sensitivity of measures to detect cognitive impairment in preclinical stages. In addition, the review revealed inconsistencies within the literature, particularly when assessing reading tasks. We urge researchers to expand on the current literature in this area and strive to assess the robustness and sensitivity of eye-tracking measures in both AD and MCI populations on naturalistic tasks.

Saccadic Eye Movements in Elderly Depressed Patients With Suicidal Behaviors: An Exploratory Eye-Tracking Study

Suicidal behaviors (SBs) are often associated with impaired performance on neuropsychological executive functioning (EF) measures that encourage the development of more specific and reliable tools. Recent evidence could suggest that saccadic movement using eye tracking can provide reliable information on EF in depressive elderly. The aim of this study was to describe oculomotor performances in elderly depressed patients with SB. To achieve this aim, we compared saccadic eye movement (SEM) performances in elderly depressed patients (N = 24) with SB and with no SB in prosaccade (PS) and antisaccade (AS) tasks under the gap, step, and overlap conditions. All participants also underwent a complete neuropsychological battery. Performances were impaired in patients with SB who exhibited less corrected AS errors and longer time to correct them than patients with no SB. Moreover, both groups had a similar performance for PS latencies and correct AS. These preliminary results suggested higher cognitive inflexibility in suicidal patients compared to non-suicidal. This inflexibility may explain the difficulty of the depressed elderly in generating solutions to the resurgence of suicidal ideation (SI) to respond adequately to stressful environments. The assessment of eye movement parameters in depressed elderly patients may be a first step in identifying high-risk patients for suicide.

Comparing saccadic and manual responses in the attention network test

Attention is proposed to be a system of multiple functional networks, including alertness, orienting and executive control. A popular experimental paradigm for testing these networks and their interactions within a single design is the Attentional Networks Test (ANT) (Fan et al., 2002). The role of the oculomotor system in these various networks, however, has not been tested despite the strong link between attention and eye movements. We modified the executive control component of the manual response ANT version (ANTm) that allows testing the networks' involvement with oculomotor responses. Specifically, we used a central target to signal pro or anti-saccades that allows us to match the saccadic response compatibility of the original ANTm. We conducted three experiments to compare interactions of the networks between the traditional ANTm that used a flanker task response, our new ANTs with saccadic responses signalled with a fixation arrow, and a manual response version with the response arrow at fixation (ANTf). Results for all three experiments showed typical main effects of all three attention networks, but we observed differences in their interactions. The ANTm showed only an interaction of alerting enhancing the orienting; ANTs showed a congruency by orienting interaction with the orienting effect only observed for pro-saccades. The ANTf showed both alerting by orienting, and orienting by congruency. Although the saccadic response did differ from the original ANTm, key differences were also highlighted by the switch from peripheral to central target. Overall the proposed ANTf is a valid tool to test main effects of attentional networks. Further investigation of interaction differences between manual and oculomotor systems is required.

The Monash Autism-ADHD genetics and neurodevelopment (MAGNET) project design and methodologies: a dimensional approach to understanding neurobiological and genetic aetiology

Background

ASD and ADHD are prevalent neurodevelopmental disorders that frequently co-occur and have strong evidence for a degree of shared genetic aetiology. Behavioural and neurocognitive heterogeneity in ASD and ADHD has hampered attempts to map the underlying genetics and neurobiology, predict intervention response, and improve diagnostic accuracy. Moving away from categorical conceptualisations of psychopathology to a dimensional approach is anticipated to facilitate discovery of data-driven clusters and enhance our understanding of the neurobiological and genetic aetiology of these conditions. The Monash Autism-ADHD genetics and neurodevelopment (MAGNET) project is one of the first large-scale, family-based studies to take a truly transdiagnostic approach to ASD and ADHD. Using a comprehensive phenotyping protocol capturing dimensional traits central to ASD and ADHD, the MAGNET project aims to identify data-driven clusters across ADHD-ASD spectra using deep phenotyping of symptoms and behaviours; investigate the degree of familiality for different dimensional ASD-ADHD phenotypes and clusters; and map the neurocognitive, brain imaging, and genetic correlates of these data-driven symptom-based clusters.

Methods

The MAGNET project will recruit 1,200 families with children who are either typically developing, or who display elevated ASD, ADHD, or ASD-ADHD traits, in addition to affected and unaffected biological siblings of probands, and parents. All children will be comprehensively phenotyped for behavioural symptoms, comorbidities, neurocognitive and neuroimaging traits and genetics.

Conclusion

The MAGNET project will be the first large-scale family study to take a transdiagnostic approach to ASD-ADHD, utilising deep phenotyping across behavioural, neurocognitive, brain imaging and genetic measures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13229-021-00457-3.

Oculomotor inhibition and location priming in schizophrenia

Schizophrenia is widely thought to involve elevated distractibility, which may reflect a general impairment in top-down inhibitory processes. Schizophrenia also appears to involve increased priming of previously performed actions. Here, we used a highly refined eye-tracking paradigm that makes it possible to concurrently assess distractibility, inhibition, and priming. In both healthy control subjects (HCS, N = 41) and people with schizophrenia (PSZ, N = 46), we found that initial saccades were actually less likely to be directed toward a salient "singleton" distractor than toward less salient distractors, reflecting top-down suppression of the singleton. Remarkably, this oculomotor suppression effect was as strong or stronger in PSZ than in HCS, indicating intact inhibitory control. In addition, saccades were frequently directed to the location of the previous-trial target in both groups, but this priming effect was much stronger in PSZ than in HCS. Indeed, PSZ directed gaze toward the location of the previous-trial target as often as they directed gaze to the location of the current-trial target. These results demonstrate that-at least in the context of visual search-PSZ are no more distractable than HCS and are fully capable of inhibiting salient-but-irrelevant stimuli. However, PSZ do exhibit exaggerated priming, focusing on recently attended locations even when this is not beneficial for goal attainment. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Collicular circuits for flexible sensorimotor routing

Context-based sensorimotor routing is a hallmark of executive control. Pharmacological inactivations in rats have implicated the midbrain superior colliculus (SC) in this process. But what specific role is this, and what circuit mechanisms support it? Here we report a subset of rat SC neurons that instantiate a specific link between the representations of context and motor choice. Moreover, these neurons encode animals' choice far earlier than other neurons in the SC or in the frontal cortex, suggesting that their neural dynamics lead choice computation. Optogenetic inactivations revealed that SC activity during context encoding is necessary for choice behavior, even while that choice behavior is robust to inactivations during choice formation. Searches for SC circuit models matching our experimental results identified key circuit predictions while revealing some a priori expected features as unnecessary. Our results reveal circuit mechanisms within the SC that implement response inhibition and context-based vector inversion during executive control.

Distinct neural networks associated with obsession and delusion: a connectome-wide association study

BACKGROUND

Obsession and delusion are theoretically distinct from each other in terms of reality testing. Despite such phenomenological distinction, no extant studies have examined the identification of common and distinct neural correlates of obsession and delusion by employing biologically grounded methods. Here, we investigated dimensional effects of obsession and delusion spanning across the traditional diagnostic boundaries reflected upon the resting-state functional connectivity (RSFC) using connectome-wide association studies (CWAS).

METHODS

Our study sample comprised of 96 patients with obsessive-compulsive disorder, 75 patients with schizophrenia, and 65 healthy controls. A connectome-wide analysis was conducted to examine the relationship between obsession and delusion severity and RFSC using multivariate distance-based matrix regression.

RESULTS

Obsession was associated with the supplementary motor area, precentral gyrus, and superior parietal lobule, while delusion was associated with the precuneus. Follow-up seed-based RSFC and modularity analyses revealed that obsession was related to aberrant inter-network connectivity strength. Additional inter-network analyses demonstrated the association between obsession severity and inter-network connectivity between the frontoparietal control network and the dorsal attention network.

CONCLUSIONS

Our CWAS study based on the Research Domain Criteria (RDoC) provides novel evidence for the circuit-level functional dysconnectivity associated with obsession and delusion severity across diagnostic boundaries. Further refinement and accumulation of biomarkers from studies embedded within the RDoC framework would provide useful information in treating individuals who have some obsession or delusion symptoms but cannot be identified by the category of clinical symptoms alone.

Neuromodulation of Persistent Activity and Working Memory Circuitry in Primate Prefrontal Cortex by Muscarinic Receptors

Neuromodulation by acetylcholine plays a vital role in shaping the physiology and functions of cerebral cortex. Cholinergic neuromodulation influences brain-state transitions, controls the gating of cortical sensory stimulus responses, and has been shown to influence the generation and maintenance of persistent activity in prefrontal cortex. Here we review our current understanding of the role of muscarinic cholinergic receptors in primate prefrontal cortex during its engagement in the performance of working memory tasks. We summarize the localization of muscarinic receptors in prefrontal cortex, review the effects of muscarinic neuromodulation on arousal, working memory and cognitive control tasks, and describe the effects of muscarinic M1 receptor stimulation and blockade on the generation and maintenance of persistent activity of prefrontal neurons encoding working memory representations. Recent studies describing the pharmacological effects of M1 receptors on prefrontal persistent activity demonstrate the heterogeneity of muscarinic actions and delineate unexpected modulatory effects discovered in primate prefrontal cortex when compared with studies in rodents. Understanding the underlying mechanisms by which muscarinic receptors regulate prefrontal cognitive control circuitry will inform the search of muscarinic-based therapeutic targets in the treatment of neuropsychiatric disorders.

Investigating Arousal, Saccade Preparation, and Global Luminance Effects on Microsaccade Behavior

Microsaccades, small saccadic eye movements occurring during fixation, have been suggested to be modulated by various sensory, cognitive, and affective processes relating to arousal. Although the modulation of fatigue-related arousal on microsaccade behavior has previously been characterized, the influence of other aspects of arousal, such as emotional arousal, is less understood. Moreover, microsaccades are modulated by cognitive processes (e.g., voluntary saccade preparation) that could also be linked to arousal. To investigate the influence of emotional arousal, saccade preparation, and global luminance levels on microsaccade behavior, emotional auditory stimuli were presented prior to the onset of a fixation cue whose color indicated to look either at the peripheral stimulus (pro-saccade) or in the opposite direction of the stimulus (anti-saccade). Microsaccade behavior was found to be significantly modulated by saccade preparation and global luminance level, but not emotional arousal. In the pro- and anti-saccade task, microsaccade rate was lower during anti-saccade preparation as compared to pro-saccade preparation, though microsaccade dynamics were comparable during both trial types. Our results reveal a differential role of arousal linked to emotion, fatigue, saccade preparation, and global luminance level on microsaccade behavior.

Neural modeling of antisaccade performance of healthy controls and early Huntington's disease patients

Huntington's disease (HD), a genetically determined neurodegenerative disease, is positively correlated with eye movement abnormalities in decision making. The antisaccade conflict paradigm has been widely used to study response inhibition in eye movements, and reliable performance deficits in HD subjects have been observed, including a greater number and timing of direction errors. We recorded the error rates and response latencies of early HD patients and healthy age-matched controls performing the mirror antisaccade task. HD participants displayed slower and more variable antisaccade latencies and increased error rates relative to healthy controls. A competitive accumulator-to-threshold neural model was then employed to quantitatively simulate the controls' and patients' reaction latencies and error rates and uncover the mechanisms giving rise to the observed HD antisaccade deficits. Our simulations showed that (1) a more gradual and noisy rate of accumulation of evidence by HD patients is responsible for the observed prolonged and more variable antisaccade latencies in early HD; (2) the confidence level of early HD patients making a decision is unaffected by the disease; and (3) the antisaccade performance of healthy controls and early HD patients is the end product of a neural lateral competition (inhibition) between a correct and an erroneous decision process, and not the end product of a third top-down stop signal suppressing the erroneous decision process as many have speculated.

Effects of pupillary light and darkness reflex on the generation of pro- And anti-saccades

Saccades are often directed toward a stimulus that provides useful information for observers to navigate the visual world. The quality of visual signals of a stimulus is influenced by global luminance, and the pupil constricts or dilates after a luminance increase or decrease, respectively, to optimize visual signals for further information processing. Although luminance level changes regularly in the real environment, saccades are mostly studied in the luminance-unchanged setup. Whether pupillary responses triggered by global luminance changes modulate saccadic behavior are yet to be explored. Through varying background luminance level in an interleaved pro- and anti-saccade paradigm, we investigated the modulation of pupillary luminance responses on the generation of reflexive and voluntary saccades. Subjects were instructed to either automatically look at the peripheral stimulus (pro-saccade) or to suppress the automatic response and voluntarily look in the opposite direction from the stimulus (anti-saccade). Level of background luminance was increased (light), decreased (dark), or unchanged (control) during the instructed fixation period. Saccade reaction time distributions of correct pro- and anti-saccades in the light and dark conditions were differed significantly from those in the control condition. Moreover, the luminance condition modulated saccade kinematics, showing reduced performances in the light condition than in the control condition, particularly in pro-saccades. Modeling results further suggested that both pupil diameter and pupil size derivative significantly modulated saccade behavior, though effect sizes were small and mainly mediated by intersubject differences. Together, our results demonstrated the influence of pupillary luminance responses on the generation of pro- and anti-saccades.

Schizotypy, neuroticism, and saccadic eye movements: New data and meta-analysis

Deficits on saccade tasks, particularly antisaccade performance, have been reliably reported in schizophrenia. However, less evidence is available on saccade performance in relation to schizotypy, a personality constellation harboring risk for schizophrenia. Here, we report a large empirical study of the associations of schizotypy and neuroticism with antisaccade and prosaccade performance (Study I). Additionally, we carried out meta-analyses of the association between schizotypy and antisaccade error rate (Study II). In Study I, N = 526 healthy individuals from the general population aged 18-54 years completed prosaccade and antisaccade tasks as well as the Schizotypal Personality Questionnaire (SPQ). Schizotypy was significantly associated with increased antisaccade error rate, with the disorganized dimension emerging as strongest predictor (β = .118, p = .007). Neuroticism emerged as a significant predictor for prosaccade gain (β = .103, p = .023) and antisaccade latency (β = .101, p = .025). In Study II, random-effects meta-analyses were performed on the published data and those from Study I. Meta-analyses revealed significant associations (all p ≤ .003) of antisaccade error rate with positive (g = 0.37), negative (g = 0.26), disorganized (g = 0.36) and overall schizotypy (g = 0.37). Overall, the present work replicates the association between antisaccade direction errors and schizotypy. Significant findings from meta-analyses provide further evidence of the antisaccade error rate as a putative schizophrenia spectrum marker.

Flexible Working Memory Through Selective Gating and Attentional Tagging

Working memory is essential: it serves to guide intelligent behavior of humans and nonhuman primates when task-relevant stimuli are no longer present to the senses. Moreover, complex tasks often require that multiple working memory representations can be flexibly and independently maintained, prioritized, and updated according to changing task demands. Thus far, neural network models of working memory have been unable to offer an integrative account of how such control mechanisms can be acquired in a biologically plausible manner. Here, we present WorkMATe, a neural network architecture that models cognitive control over working memory content and learns the appropriate control operations needed to solve complex working memory tasks. Key components of the model include a gated memory circuit that is controlled by internal actions, encoding sensory information through untrained connections, and a neural circuit that matches sensory inputs to memory content. The network is trained by means of a biologically plausible reinforcement learning rule that relies on attentional feedback and reward prediction errors to guide synaptic updates. We demonstrate that the model successfully acquires policies to solve classical working memory tasks, such as delayed recognition and delayed pro-saccade/anti-saccade tasks. In addition, the model solves much more complex tasks, including the hierarchical 12-AX task or the ABAB ordered recognition task, both of which demand an agent to independently store and updated multiple items separately in memory. Furthermore, the control strategies that the model acquires for these tasks subsequently generalize to new task contexts with novel stimuli, thus bringing symbolic production rule qualities to a neural network architecture. As such, WorkMATe provides a new solution for the neural implementation of flexible memory control.

The YOUth study: Rationale, design, and study procedures

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This article describes the rationale, design, and procedures of the YOUth cohort.

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YOUth is set up to investigate what drives the development of social competence and self-regulation in children.

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YOUth specifically investigates the role of neurocognitive development in child development.

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YOUth has a flexible longitudinal design with repeated measurements throughout childhood, starting prenatally.

Behavioral development in children shows large inter-individual variation, and is driven by the interplay between biological, psychological, and environmental processes. However, there is still little insight into how these processes interact. The YOUth cohort specifically focuses on two core characteristics of behavioral development: social competence and self-regulation. Social competence refers to the ability to engage in meaningful interactions with others, whereas self-regulation is the ability to control one’s emotions, behavior, and impulses, to balance between reactivity and control of the reaction, and to adjust to the prevailing environment. YOUth is an accelerated population-based longitudinal cohort study with repeated measurements, centering on two groups: YOUth Baby & Child and YOUth Child & Adolescent. YOUth Baby & Child aims to include 3,000 pregnant women, their partners and children, wheras YOUth Child & Adolescent aims to include 2,000 children aged between 8 and 10 years old and their parents. All participants will be followed for at least 6 years, and potentially longer.

In this paper we describe in detail the design of this study, the population included, the determinants, intermediate neurocognitive measures and outcomes included in the study. Furthermore, we describe in detail the procedures of inclusion, informed consent, and study participation.