Hippocampal Signal Complexity and Rate-of-Change Predict Navigational Performance: Evidence from a Two-Week VR Training Program.

The hippocampus is believed to be an important region for spatial navigation, helping to represent the environment and plan routes. Evidence from rodents has suggested that the hippocampus processes information in a graded manner along its long-axis, with anterior regions encoding coarse information and posterior regions encoding fine-grained information. Brunec et al. (2018) demonstrated similar patterns in humans in a navigation paradigm, showing that the anterior-posterior gradient in representational granularity and the rate of signal change exist in the human hippocampus. However, the stability of these signals and their relationship to navigational performance remain unclear. In this study, we conducted a two-week training program where participants learned to navigate through a novel city environment. We investigated inter-voxel similarity (IVS) and temporal auto-correlation hippocampal signals, measures of representational granularity and signal change, respectively. Specifically, we investigated how these signals were influenced by navigational ability (i.e., stronger vs. weaker spatial learners), training session, and navigational dynamics. Our results revealed that stronger learners exhibited a clear anterior-posterior distinction in IVS in the right hippocampus, while weaker learners showed less pronounced distinctions. Additionally, lower general IVS levels in the hippocampus were linked to better early learning. Successful navigation was characterized by faster signal change, particularly in the anterior hippocampus, whereas failed navigation lacked the anterior-posterior distinction in signal change. These findings suggest that signal complexity and signal change in the hippocampus are important factors for successful navigation, with IVS representing information organization and auto-correlation reflecting moment-to-moment updating. These findings support the idea that efficient organization of scales of representation in an environment may be necessary for efficient navigation itself. Understanding the dynamics of these neural signals provides insights into the mechanisms underlying navigational learning in humans.

Examining the influence of substance use on mental health rating during COVID-19: A Canadian perspective.

Introduction: Substance use and mental health symptoms (e.g., depression and anxiety) have increased during the COVID-19 pandemic, partly due to implementation of physical distancing measures aimed at containing the spread of the SARS-CoV-2 virus. However, there is limited pandemic-specific research that has examined the relationship between substance use and mental health with other correlates of well-being, including life satisfaction and social confidants. Methods: In the current study, we used ordered logistic regression analyses to examine whether a greater frequency of substance use (e.g., alcohol, cannabis, and opioids) during the pandemic predicted poorer ratings of self-reported mental health in a large sample of Canadians aged 15 to 64 years. We further considered whether life satisfaction and number of social confidants interacted with substance use to influence mental health, and stratified the models by sex and personal feelings of shame surrounding the use of substances (i.e., high and low shame). Results: Findings indicated that frequency of substance use was significantly associated with increased odds of reporting poorer mental health for males and females exhibiting both low and high shame. In females reporting low shame, we found that as frequency of cannabis use increased, life satisfaction has a much greater positive association with mental health. Whereas, in females disclosing high shame, maintaining social relations was particularly important to benefit the mental health of current users of opioids, relative to past and non-users. No such interaction was found in males. Discussion: Overall, the findings of the current study showed the negative mental health consequences of substance use during COVID-19 in a large Canadian sample, and most importantly revealed a critical sex difference in the way in which social determinants interact with substance use to influence mental health.

Enhancing memory using enactment: does meaning matter in action production?

ABSTRACTEnactment is an encoding strategy in which performing an action related to a target item enhances memory for that word, relative to verbal encoding. Precisely how this motor activity aids recall is unclear. We examined whether the action created during encoding needed to be semantically relevant to the to-be-remembered word, to enhance memory. In Experiment 1, participants were asked to either (a) enact, (b) perform unrelated motoric gestures, or (c) read forty-five action verbs. On a subsequent free-recall test, memory for enacted words was significantly higher relative to words read, or encoded with unrelated gestures. In Experiment 2, to reduce the ambiguity associated with initiating an unrelated gesture, participants were instructed to write target words in the air. Results were similar to Experiment 1. In Experiment 3, we replicated the results of Experiment 2 using video conferencing to record the onset time of action initiation for enacted, unrelated gesture, and read trials. Results showed that planning of meaningful actions may also contribute to the memory performance as evidenced by a longer onset time to initiate an action on enactment relative to gesturing and reading trials. These findings suggest that planning and executing meaningful actions drive the enactment benefit.

Virtual tourism for older adults living in residential care: A mixed-methods study.

Due to financial and mobility barriers, a majority of older adults living in collective dwellings are no longer able to engage in tourism, a leisure activity that contributes to quality of life and wellbeing. Immersive Virtual Reality (VR) may serve as a programmatic tool to facilitate tourism. This pilot study examined the effects of VR tourism exposure on indices of psychosocial wellbeing among older adults living in residential care. Using a mixed-methods study design, 18 older adults were exposed to VR tourism three times a week, over six weeks. Participants reported decreased anxiety and fatigue immediately following exposure, and increased social engagement and quality of life following six weeks of VR tourism. Qualitative data offered additional insight on the process by which VR tourism may enhance wellbeing. Findings suggest that immersive VR tourism may be a viable program for older adults in residential care.