Biology subjects

Hinrichs, S.

Publications and source records attributed to Hinrichs, S..

3 recordsLinked to original sources

bioRxiv2025

Wide visual angle enhances social interaction in a realistic virtual reality environment under simulated artificial vision

Objective. Social interaction largely relies on visual perception. Yet artificial vision research has primarily focused on navigation and object recognition while assessment of social interaction remains scarce. This study investigates how the visual field size in simulated artificial vision impacts social perception in a virtual reality setting. Approach. We assessed the impact of visual field size in sighted participants experiencing simulated artificial vision in a medical practice across three social task categories: indoor identification (searching for an empty chair, identification of body orientation, body appearance, facial expressions, relationship type, role and interpretation of body language), locomotion (tracking and following a moving person), and outdoor observation (person recognition in a cluttered outdoor environment). Main Results. A wide range of social perception and locomotion tasks in structured indoor environments can be completed with a 45{degrees} field of view in simulated artificial vision. Compared to 20{degrees}, the broader visual field not only enhances accuracy but also enables faster task execution and a more precise assessment of ones own performance. Although the benefits of an expanded visual field are limited in cluttered environments, a 45{degrees} visual field represents a clear advantage in social contexts. Significance. These findings highlight the importance of an expanded visual field for artificial vision users in social settings, reinforcing its role in enhancing social cue processing and the ability to follow people. By integrating simulated artificial vision within an immersive virtual reality framework, this study bridges the gap between controlled experimental paradigms and real-world needs and challenges.

bioengineering↗

bioRxiv2023

Neural signatures of declarative memory cueing using odors during sleep

Long-term memories are formed by repeated reactivation of newly encoded information during sleep. This process can be enhanced by using memory-associated reminder cues like sounds and odors. While auditory cueing has been researched extensively, few electrophysiological studies have exploited the various benefits of olfactory cueing. We used high-density electroencephalography in an odor-cueing paradigm that was designed to isolate the neural responses specific to the cueing of declarative memories. We show widespread cueing-induced increases in the duration and rate of sleep spindles. Higher spindle rates were most prominent over centro-parietal areas and largely overlapping with a concurrent increase in the amplitude of slow oscillations (SOs). Interestingly, greater SO amplitudes were linked to a higher likelihood of coupling a spindle and coupled spindles expressed during cueing were more numerous in particular around SO up states. We thus identify temporally and spatially coordinated enhancements to sleep spindles and slow oscillations as a candidate mechanism behind the benefits of odor cueing. Our results further demonstrate the feasibility of studying neural activity patterns related to memory processing using olfactory cueing during sleep. Statement of SignificanceMemory cueing during sleep allows insights into memory consolidation. This study is the first to investigate olfactory cueing-induced declarative memory processing using high-density EEG, while robustly controlling for critical confounding factors. The use of odors as cues, instead of more common auditory stimuli, further minimizes possible distortions due to sensory-evoked potentials. We demonstrate intricate changes in brain activity in response to cueing, such as the patterns of sleep spindles, slow oscillations, and their spatiotemporal coupling. We provide evidence that the enhancement of slow oscillation amplitudes, together with associated increases in sleep spindle rates, could be the key mechanism behind cueing-related memory benefits. We moreover show that prior findings obtained using auditory cueing are not the mere result of tone-evoked responses but might be genuine signatures of memory processing.

neuroscience↗

bioRxiv2021

Virtual reality validation of naturalistic modulation strategies to counteract fading in retinal stimulation

ObjectiveTemporal resolution is a key challenge in artificial vision. Several prosthetic approaches are limited by the perceptual fading of evoked phosphenes upon repeated stimulation from the same electrode. Therefore, implanted patients are forced to perform active scanning, via head movements, to refresh the visual field viewed by the camera. However, active scanning is a draining task, and it is crucial to find compensatory strategies to reduce it. ApproachTo address this question, we implemented perceptual fading in simulated prosthetic vision using virtual reality. Then, we quantified the effect of fading on two indicators: the time to complete a reading task and the head rotation during the task. We also tested if stimulation strategies previously proposed to increase the persistence of responses in retinal ganglion cells to electrical stimulation could improve these indicators. Main resultsThis study shows that stimulation strategies based on interrupted pulse trains and randomisation of the pulse duration allows significant reduction of both the time to complete the task and the head rotation during the task. SignificanceThe stimulation strategy used in retinal implants is crucial to counteract perceptual fading and to reduce active head scanning during prosthetic vision. In turn, less active scanning might improve the patients comfort in artificial vision.

bioengineering↗