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Previous work from our lab has shown that basal cortisol levels are different between healthy young adults who spontaneously use caudate nucleus-dependent response strategies compared to young adults who use hippocampus-dependent spatial navigation strategies. Young adults who use caudate nucleus dependent strategies display lower basal cortisol levels compared to those who use hippocampus-dependent strategies. In the current study, we assessed navigation strategies in children using a virtual navigation task and measured cortisol at baseline as well as cortisol reactivity to both a psychological and to a physical stressor. Replicating what is observed in adults, we found that children who used caudate nucleus-dependent navigation strategies displayed lower cortisol levels at baseline compared to those who used hippocampus-dependent strategies. The psychological stressor, knowledge that a blood draw would be performed by a nurse, caused a significant increase in cortisol uniquely in response learners. The physical stressor, the actual blood draw, produced a significant increase in cortisol amongst spatial learners that was then comparable to levels observed in response learners. Lower baseline cortisol and higher cortisol psychological stress response observed amongst children who used response strategies may therefore reflect early biological changes during development which may have an impact later in life when considering risk for neuropsychiatric disorders.

When people navigate, they use strategies dependent on one of two memory systems. The hippocampus-based spatial strategy consists of using multiple landmarks to create a cognitive map of the environment. In contrast, the caudate nucleus-based response strategy is based on the memorization of a series of turns. Importantly, response learners display more gray matter and functional activity in the caudate nucleus and less gray matter in the hippocampus. In parallel, the caudate nucleus is involved in decision-making by mediating attention toward rewards and in set-shifting by mediating preparatory actions. The present study, therefore, examined the link between navigational strategy use, that are associated with gray matter differences in the caudate nucleus and hippocampus, and decision-making and set-shifting performance. Fifty-three participants completed the 4 on 8 virtual maze, the Iowa Gambling Task (IGT), the Wisconsin Card Sorting Test-64 (WCST-64), and a task-switching test. The results revealed that people who use response strategies displayed increased risk-taking behavior in the IGT compared to the people using hippocampus-dependent spatial strategies. Response strategy was also associated with enhanced set-shifting performance in the WCST-64 and task-switching test. These results confirm that risk-taking and set-shifting behavior, that are differentially impacted by the caudate nucleus and hippocampus memory systems, can be predicted by navigational strategy.

Sex differences in navigation have been a topic of investigation for decades and has been subjected to various contradictory findings and debates. The aim of this work was to compare the spatial memory of men and women tested in various different types of spatial tasks, while controlling for navigation strategies and aging. It is generally thought thatmen outperformwomen in navigation and that women have higher scores on object location tasks. However, many studies fail to control for different factors that may bias one sex or the other. We aggregated the data of 465 participants (349 young adults, 127 older adults) who took part in various studies conducted in our laboratory, which include both published and original unpublished data, in order to investigate sex differences. In these studies, we used a number of different paradigms: virtual radial arm mazes, a virtual wayfinding task, an object location task, a virtual Morris Water Maze, and the invisible sensor task which is a real-life model of the Morris Water Maze. While our results may seem discordant at first glance, they demonstrate that several factors can impact the performance of men and women on spatial tasks, including spontaneous navigation strategies, environmental characteristics, and age. Wereplicated findings showing thatwomen favor proximal landmarks compared to men who favor distal landmarks, women have better memory than men for the position of objects in the absence of reference frames, but they will have poorer scores when navigation requires specific angles, distances and polar coordinates. Moreover, we found that in aging, women who avoid the use of landmarks when navigating a radial maze show stronger reliance on these non-spatial strategies than men. On the other hand, women who rely on landmarks, do so to the same extent asmen. Our findings highlight the need to carefully take into consideration these factors in order to produce amore harmonious understanding of sex differences in navigation. Finally, the interaction between spontaneous navigation strategies, sex, and age is discussed in terms of its implications for risk of Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Background: The extent to which digital media use by adolescents contributes to poor mental health, or vice-versa, remains unclear. The purpose of the present study is to clarify the strength and direction of associations between adolescent internet use and the development of depression symptoms using a longitudinal modeling approach. We also examine whether associations differ for boys and girls. Methods: Data are drawn from (N = 1547) participants followed for the Quebec longitudinal Study of Child Development (QLSCD 1998–2020). Youth self-reported internet use in terms of the average hours of use per week at the ages of 13, 15, and 17. Youth also self-reported depression symptoms at the same ages. Results: After testing sex-invariance, random intercepts cross-lagged panel models stratified by sex, revealed that internet use by girls was associated with significant within-person (time-varying) change in depression symptoms. Girl's internet use at age 13 was associated with increased depression symptoms at age 15 (ß = 0.12) and internet use at age 15 increased depression at age 17 (ß = 0.10). For boys, internet use was not associated with significant time varying change in depression symptoms. Conclusions: The present findings support the hypothesis that internet use by adolescents can represent a significant risk factor for the development of depressive symptoms, particularly in girls. [ABSTRACT FROM AUTHOR]

The present study examined development-related differences in saccade curvature during a goal-directed saccade task in the presence of distracting visual information. Participants were individuals who ranged in age from 6 to 30 years. Consistent with previous findings, all participants showed curvature toward the distractor stimulus at shorter saccadic reaction times (SRTs). Chronological age, however, was positively related to participants' ability to inhibit distracting information as revealed by curvature away from the distractor stimulus at longer SRTs. Interestingly, no significant differences in saccadic reaction times were observed. Results are discussed in the context of similar findings comparing older and younger adults and the putative frontal neural mechanisms that contribute to the observed developmental effect. Our present results suggest that saccadic curvature can be used a tool to measure fontal-oculomotor control interaction across the life span and can be further used to examine inhibitory functioning in special pediatric populations (e.g., having brain trauma, attention-deficit/hyperactivity disorder, frontal epilepsy).

The present study investigated the mechanisms responsible for the difference between visual processing of stimuli near and far from the observer's hands. The idea that objects near the hands are immediate candidates for action led us to hypothesize that vision near the hands would be biased toward the action-oriented magnocellular visual pathway that supports processing with high temporal resolution but low spatial resolution. Conversely, objects away from the hands are not immediate candidates for action and, therefore, would benefit from a bias toward the perception-oriented parvocellular visual pathway that supports processing with high spatial resolution but low temporal resolution. We tested this hypothesis based on the psychophysical characteristics of the two pathways. Namely, we presented subjects with two tasks: a temporal-gap detection task which required the high temporal acuity of the magnocellular pathway and a spatial-gap detection task that required the spatial acuity of the parvocellular pathway. Consistent with our prediction, we found better performance on the temporal-gap detection task and worse performance on the spatial-gap detection task when stimuli were presented near the hands compared to when they were far from the hands. These findings suggest that altered visual processing near the hands may be due to changes in the contribution of the two visual pathways. (Contains 3 figures.)

Previous studies that have found attentional capture effects for stimuli of motivational significance do not directly measure initial attentional deployment, leaving it unclear to what extent these items produce attentional capture. Visual prior entry, as measured by temporal order judgments (TOJs), rests on the premise that allocated attention accelerates perception, that is, stimuli that receive attention first are perceived first; thus, this method is a sensitive and direct measure of the time course of initial attentional deployment. The authors demonstrate, using a novel TOJ paradigm without cues, that displays of faces and facial threat show visual prior entry effects, that is, these stimuli are prioritized by the perceptual-attentional system over other stimuli competing for awareness. This study provides direct evidence of the extent to which motivationally significant stimuli capture attention over other concurrently displayed items in the visual array. (Contains 4 figures.)

ABSTRACT. Although a considerable amount of research has investigated the planning and production of saccadic eye movements, it remains unclear whether (a) central planning processes prior to movement onset largely [...]

Language is critical to social identity, including nationality. However, some nations encompass multiple languages, raising questions about how their citizens perceive members of their national versus linguistic groups. We explored perceptions of Canadian nationality, which consists of two linguistic groups: Anglo-Canadians and Franco-Canadians. In Study 1, we used reverse correlation methods to visualize how Anglo- and Franco-Canadians mentally represent the faces of linguistic ingroup and outgroup members, and of Canadians in general. Structural similarity analyses and subjective ratings of the resulting images showed that both groups mentally represented Canadians as more similar to their own linguistic ingroup. In Study 2, Anglo-Canadians and Franco-Canadians rated photos of real Anglo- and Franco-Canadian targets. Both samples showed some ingroup favoritism when inferring their traits but only Anglo-Canadians could accurately differentiate group members. Differences between Anglo-Canadians and Franco-Canadians therefore extend beyond language, with linguistic groups impacting impressions before any words are spoken. [ABSTRACT FROM AUTHOR]

People adopt two distinct learning strategies during navigation. "Spatial learners" navigate by building a cognitive map using environmental landmarks, and display more grey matter in the hippocampus. Conversely, "response learners" memorize a series of rigid turns to navigate and display more grey matter in the caudate nucleus of the striatum. Evidence has linked these two structures with autism spectrum disorder (ASD) and autistic traits in non‐clinical populations. Both people with ASD and neurotypical people with higher levels of autistic traits have been shown to display more grey matter in the hippocampus and less functional activity in the caudate nucleus. We therefore tested 56 healthy participants who completed the Autism Quotient (AQ) Scale and the 4‐on‐8 Virtual Maze (4/8 VM), which determines the reliance on landmarks during navigation. We found that people who relied on landmarks during navigation also displayed significantly higher scores on the AQ Scale. Because spatial strategies are associated with increased attention to environmental landmark use and are supported by the hippocampus, our results provide a potential behavioral mechanism linking higher autistic traits (e.g., increased attention to detail and increased sensory processes) to increased hippocampal grey matter. [ABSTRACT FROM AUTHOR]

Visuospatial experience, the prolonged engagement in a demanding visual task, obtained through action video game play enhances several visual and cognitive processes. The underlying mechanisms involved in these processes, however, remain unclear. Here we demonstrate that experience with action video games modulates early sensory processing, resulting in increases sensitivity to salient visual events that capture attention. In two experiments, we show using a Temporal Order Judgment (TOJ) and a Signal Detection Paradigm (d') that action video game players show greater sensitivity to exogenous sensory events in the visual array. These results suggest that visuospatial experience modulates the earliest sensory aspects of visual processing.