Biology subjects

Mikulasch, F. A.

Publications and source records attributed to Mikulasch, F. A..

3 recordsLinked to original sources

bioRxiv2024

Power-law adaptation in the presynaptic vesicle cycle

After synaptic transmission, fused synaptic vesicles are recycled, enabling the synapse to recover its capacity for renewed release. The recovery steps, which range from endocytosis to vesicle docking and priming, have been studied individually, but it is not clear what their impact on the overall dynamics of synaptic recycling is, and how they influence signal transmission. Here we model the dynamics of vesicle recycling and find that the multiple timescales of the recycling steps are reflected in synaptic recovery. This leads to multi-timescale synapse dynamics, which can be described by a simplified synaptic model with power-law adaptation. Using cultured hippocampal neurons, we test this model experimentally, and show that the duration of synaptic exhaustion changes the effective synaptic recovery timescale, as predicted by the model. Finally, we show that this adaptation could implement a specific function in the hippocampus, namely enabling efficient communication between neurons through the temporal whitening of hippocampal spike trains.

neuroscience↗

bioRxiv2023

Prediction mismatch responses arise as corrections of a predictive spiking code

Prediction mismatch responses in cortex seem to signal the difference between an internal model of the animal and sensory observations. Often these responses are interpreted as evidence for the existence of error neurons, which guide inference in models of hierarchical predictive coding. Here we show that prediction mismatch responses also arise naturally in a spiking encoding of sensory signals, where spikes predict the future signal. In this model, the predictive representation has to be corrected when a mispredicted stimulus appears, which requires additional neural activity. This adaptive correction could explain why mismatch response latency can vary with mismatch detection difficulty, as the network gathers sensory evidence before committing to a correction. Prediction mismatch responses thus might not reflect the computation of errors per se, but rather the reorganization of the neural code when new information is incorporated.

neuroscience↗

bioRxiv2022

Visuomotor mismatch responses as a hallmark of explaining away in causal inference

How are visuomotor mismatch responses in visual cortex embedded into cortical processing? We here argue that mismatch responses are best understood as the result of a cooperation of motor and visual areas to jointly explain optic flow. This cooperation ensures that optic flow is not explained redundantly by both areas, which in the language of causal inference is termed explaining away. This improves the efficiency of the resulting neural code, and allows the animal to easily detect movements that are independent of its own locomotion. We demonstrate the emergence of mismatch responses from explaining away in simulations, where spiking neurons learn to encode optic flow stimuli and locomotion. We furthermore lay out arguments against the prevailing idea that mismatch signals are the result of a dedicated error computation in a hierarchical model. These results provide a new perspective on several recent experiments of cross-modal neural interactions in cortex.

neuroscience↗