Biology subjects

Haendel, B.

Publications and source records attributed to Haendel, B..

5 recordsLinked to original sources

bioRxiv2022

Modelling non-local neural information processing in the brain

The representation of the surrounding world emerges through integration of sensory information and actions. We present a novel neural model which implements non-local, parallel information processing on a neocolumnar architecture with lateral interconnections. Information is integrated into a holographic wave interference pattern. We compare the simulated in silico pattern with observed in vivo invasive and non-invasive electrophysiological data in human and non-human primates. Our model replicates the modulation of neural high-frequency activity during visual perception showing that phase-locked low and high-frequency oscillations self-organize efficiently and carry high information content. The simulation further models how criticality (high content) of information processing emerges given a sufficiently high number of correlated neurons. Non-local information processing, forming one holographic wave pattern, suggests a platform for emergence of conscious perception. One sentence summarySimulated non-local information processing on a neocolumnar architecture models well multiple electrophysiological observations of brain activity, including high-frequency activity during visual perception in primates.

neuroscience↗

bioRxiv2020

The influence of eye movements and their retinal consequences on bistable motion perception

Eye related movements such as blinks and microsaccades are modulated during bistable perceptual tasks, however, the role of such movements in these purely internal perceptual switches is not known. We conducted two experiments involving an ambiguous plaid stimulus, wherein participants had to continuously report their motion percept. To dissociate the effect of blinks and microsaccades from the visual consequences of such eye movements, we added external blanks and microshifts. Our results showed that while blanks facilitated a switch to the coherent motion percept, this was not the case for a switch to component percept. A similar difference was found with respect to blinks. While both types of perceptual switches were preceded by a decrease in blinks, only the switch to coherent percept was followed by an increase in blinks. These blink related findings, which we largely replicated and refined in a second study, indicate distinct internal processes underlying the two perceptual switches. Microsaccade rates, on the other hand, only showed a weak relation with perceptual switches but their direction was modulated by the perceived motion direction. Additionally, our data showed that microsaccades are differently modulated around internal (blinks) and external events (blanks, microshifts), indicating an interaction between different eye related movements. This study shows that eye movements such as blinks and microsaccades are modulated by purely internal perceptual events independent of task related motor or attentional demands. Eye movements therefore can uncover distinct internal perceptual processes that might otherwise be hard to dissociate.

neuroscience↗

bioRxiv2020

How the Motor Aspect of Speaking Influences the Blink Rate

The blink rate increases if a person indulges in a conversation compared to quiet rest. Since various factors were suggested to explain this increase, the present study tested the influence of motor activity, cognitive processes and auditory input on the blink rate but at the same time excluding any social interaction. While the cognitive and auditory factors only showed a minor influence, mere mouth movements during speaking highly increased the blink rate. Even more specific, lip movements, but less jaw movements, are likely responsible for the increase during a conversation. Such purely motor related influences on the blink rate advise caution when using blinks as neurological indicators during patient interviews.

neuroscience↗

bioRxiv2020

The Latency of Spontaneous Eye Blinks Marks Relevant Visual and Auditory Information Processing

Eye blinks are influenced by several external sensory and internal cognitive factors. However, neither the precise temporal effects of these factors on blinking nor how their timing compares between modalities is known. Our aim was to understand the influence of sensory input vs task-relevant information on blinks in the visual and auditory domain. Using a visual and an auditory temporal judgement task, we found that blinks were suppressed during stimulus presentation in both domains and the overall input length had a significant positive relationship with blink latency i.e. the end of blink suppression. Indeed, the effect of sensory input duration on blink latency was not significantly different between visual and auditory stimuli. The precise timing of blink latency was further modulated by the duration of the task relevant input, which was independent of the overall length of sensory input. The influence of task related changes embedded in the overall stimulation suggests an additional influence of top-down processes on blink timing. Intriguingly, embedded changes as short as 40 ms in the auditory domain and 100 ms in the visual domain are reflected in blink latency differences. Importantly, we could show that task accuracy and motor response was not the driving factor of blink modulation. Our results show a sensory domain independent modulation of blink latencies introduced by changes in the length of task-relevant information. Therefore, blinks not only mark the time of sensory input but also can act as precise indicator for periods of cognitive processing and attention.

neuroscience↗

bioRxiv2018

Increased influence of periphery on central visual processing in humans during walking

Cognitive processes are almost exclusively investigated under highly controlled settings while voluntary body movements are suppressed. However, recent animal work suggests differences in sensory processing between movement states by showing drastically changed neural responses in early visual areas between locomotion and stillness. Does locomotion also modulate visual cortical activity in humans and what are its perceptual consequences? Here, we present converging neurophysiological and behavioural evidence that walking leads to an increased influence of peripheral stimuli on central visual input. This modulation of visual processing due to walking is encompassed by a change in alpha oscillations, which is suggestive of an attentional shift to the periphery during walking. Overall, our study shows that strategies of sensory information processing can differ between movement states. This finding further demonstrates that a comprehensive understanding of human perception and cognition critically depends on the consideration of natural behaviour.

neuroscience↗