Biology subjects

Vavra, P.

Publications and source records attributed to Vavra, P..

4 recordsLinked to original sources

bioRxiv2026

The neural signature of simple overlearned temporal expectations resembles episodic retrieval

Temporal expectations are crucial for adaptive responding to predictable events. Most previous imaging studies have focused on the neural underpinnings of unexpectedness rather than expectedness, without considering that neural responses related to temporal expectations may be confounded by parallel learning processes. To identify the neural basis of overlearned expectancy with fMRI, we employed a multi-day detection paradigm with auditory cues preceding visual targets at likely and unlikely time points. After training left inferior parietal cortex was engaged in processing overlearned temporal expectations together with retrosplenial and prefrontal cortex. Remarkably, compared with untrained controls, we observed inverted brain responses as a function of stimulus likelihood and training status. Finally, the brain regions coding overlearned expectancy had previously been implicated in episodic retrieval and simulation (based on Neurosynth association tests), suggesting that frequently used temporal expectations may, over time, utilize episodic memory routines to simulate likely future events and thus guide behavior.

neuroscience↗

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↗