Biology subjects

Vavra, P.

Publications and source records attributed to Vavra, P..

3 recordsLinked to original sources

bioRxiv2023

Preventing injuries: How augmented reality reduces fall risks in pseudo-natural environments

Falling is a major contributor to injury-related incidents and the 2nd most likely cause for unintentional injury deaths world-wide. Here, we therefore tested a vision aid for obstacle detection during a navigation task in pseudo-natural environments (virtually created cities). The vision aid had nine different setups (i.e. no highlighting of hazardous objects vs. eight different hit / false alarm ratios [cue validity]). Elderly and healthy, young adults completed the navigation task. As in real life, elderly walked slower and fell more often in pseudo-natural environments, suggesting the ecological validity of such safe experimental setups to test hazardous situations. Importantly, the vision aid reduced the risk of falling (by up to 33 %) for both age groups. Thus, our study highlights that a vision aid which augments reality could be a substantial contributor in preventing falls and related injuries, decreasing the financial burden on the health system and increasing life quality.

neuroscience↗

bioRxiv2022

Seeing and Extrapolating motion trajectories share common informative activation patterns in primary visual cortex

The natural environment is dynamic and moving objects become constantly occluded, engaging the brain in a challenging completion process to estimate where and when the object might reappear. Although motion extrapolation is critical in daily life - imagine crossing the street while an approaching car is occluded by a larger standing vehicle - its neural underpinnings are still not well understood. While the engagement of low-level visual cortex during dynamic occlusion has been postulated, most of the previous group-level fMRI-studies failed to find evidence for an involvement of low-level visual areas during occlusion. In this fMRI-study, we therefore used individually-defined retinotopic maps and multivariate pattern analysis to characterize the neural basis of visible and occluded motion in humans. To this end, participants learned velocity-direction pairings (slow motion-upwards; fast motion-downwards or vice versa) during a training phase without occlusion and judged the stimulus direction, based on its velocity, during a following test phase with occlusion. We find that occluded motion direction can be predicted from the activity patterns during visible motion within low-level visual areas, supporting the notion of a mental representation of motion trajectory in these regions during occlusion. Highlights* Dynamically occluded information is processed in low-level visual cortex * Specific regions inside low-level visual areas encode visible and dynamically occluded information * Overlap of visible and occluded informative activity patterns in the visual field suggest shared computational circuits in primary visual cortex

neuroscience↗

bioRxiv2021

Entering into a self-regulated learning mode prevents detrimental effect of feedback removal on memory

Recently, we provided causal evidence that self-regulated dopamine signaling enhanced long-term memory formation in the absence of any external feedback or reward (Ripolles et al., 2016, 2018) if a congruent meaning inferred from semantic context (DA-dependent learning), while DA-signals were absent if no congruent meaning could be inferred (DA-independent learning). Here, we investigated the interaction of self-regulated learning with externally-regulated DA-signalling by providing external performance feedback in the first or second half of trials. We found that removing feedback during DA-dependent learning lowered subsequent recognition rates a day later, whereas recognition remained high in the group which received feedback only in the second half. In contrast, feedback modestly enhanced recognition rates for both groups for DA-independent learning. Our findings suggest that external reinforcers can selectively impair DA-dependent memories if internal DA-dependent processes are not already established and highlights the relevance of self-regulated learning in education to support stable memory formation.

neuroscience↗