Biology subjects

Brazdil, M.

Publications and source records attributed to Brazdil, M..

5 recordsLinked to original sources

bioRxiv2026

Social brain fingerprinting: unique functional connectomes underpin interpersonal behaviours in non-autistic and autistic adults

Human social interaction requires continuous adaptation while preserving stable individual patterns of brain organisation. This study examined whether functional connectome fingerprinting captures person-specific organisation during reciprocal interaction and whether its spatial architecture relates to social role and autistic traits. fMRI data from 70 adults forming 35 dyads were analysed during an iterated Ultimatum Game: 19 non-autistic Proposer-non-autistic Responder dyads and 16 non-autistic Proposer-autistic Responder dyads. Functional connectivity across 400 cortical parcels was used to assess whole-brain identifiability and edge-wise reliability. Connectomes remained identifiable across datasets, roles, and task conditions, with no reduction in global identifiability in mixed dyads. Edge-wise analyses revealed role-related and dataset-dependent differences across distributed large-scale networks. Role-sensitive connectivity features were associated with Autism-Spectrum Quotient scores, supported out-of-sample prediction, and topology-derived features classified AQ-threshold status above chance. Stable connectomic signatures therefore persist during reciprocal interaction while their network organisation varies with social role and autistic traits.

neuroscience↗

bioRxiv2026

Cortical high frequency oscillations reflect encoding and retrieval of specific word concepts

High gamma and ripple frequency oscillations are engaged in encoding and recall of memory traces. Tracking specific traces with their signature neural activities across time and various tasks remains a major challenge. Using intracranial electrode recordings from epilepsy patients, we detected bursts of high-frequency oscillations in response to viewing and remembering the same common nouns in two different tasks repeated on subsequent days. We found the lowest word response selectivity of approximately 40% in the visual sensory areas and increasingly higher selectivity in the more anterior associational regions. The same word sets identified as preferred in a screening task triggered selective responses in another task during visual presentation or free recall with no sensory stimulation in the same session, and on the following day. We demonstrate that persistent reactivation of large-scale neuronal assemblies underlying particular concepts is reflected in bursts of high-frequency oscillations in the human cortex.

neuroscience↗

bioRxiv2025

Coincident bursts of high frequency oscillations across the human cortex coordinate large-scale memory processing.

Oscillations in the high gamma and ripple frequency ranges are known to coordinate local hippocampal and neocortical neuronal assemblies during memory encoding and recall. Here, we explored spatiotemporal dynamics and the role of global coordination of these fast oscillatory discharges across the sensory and associational cortical areas in distinct phases of memory processing. Individual bursts of high frequency oscillations were detected in intracranial recordings from epilepsy patients remembering word lists for immediate free recall. We found constant coincident bursting across visual and higher order processing areas, peaking before recall and elevated during encoding of words. This global co-bursting was modulated by memory processing, engaged approximately half of the recorded electrode sites, and clustered into a sequence of multiple consecutive bursting discharges. Our results suggest a general role of global coincident high frequency oscillations in organizing large-scale information processing across the brain necessary especially, but not exclusively, for memory functions.

neuroscience↗

bioRxiv2024

Cortical evidence accumulation for perceptual experience occurs irrespective of reports

Perceptual experience is a multi-faceted, dynamical process, tackled empirically through measures of stimulus detectability and confidence. To assess if stimulus detection and confidence can be explained by evidence accumulation, a form of sequential sampling of sensory evidence, we analyzed high-gamma activity from stereo-electroencephalographic data of 29 participants partaking in 3 pre-registered experiments. In an immediate-response experiment, individual channels and decoded multivariate latent variables in the visual, inferior frontal, and anterior insular cortices displayed functional markers of evidence accumulation. In two further experiments, this signal in the ventral visual cortex differentiated between (1) seen and unseen stimuli in delayed detection, (2) high and low intensity stimuli during passive viewing, and (3) levels of confidence when stimuli were seen. A computational model of leaky evidence accumulation successfully reproduced both behavioral and neural data. Overall, these results indicate that evidence accumulation explains key aspects of perceptual experience, encompassing both conscious access and monitoring.

neuroscience↗

bioRxiv2021

Biological Factors and Self-Perception of Stress Predict Human Freeze-Like Responses in the Context of Self-Defence Training and Personal Experience with Violence

Many animals react to threatening stimuli such as a predator attacks by freezing. However, little experimental research investigated freeze response in humans. Here, we have employed practices commonly used in self-defence training to create two unique scenarios simulating armed physical attacks. Sixty healthy men volunteers divided into three groups of twenty (untrained, trained but unexperienced, trained and experienced) underwent these scenarios accompanied by measurement of biochemical, physiological, and psychological markers of stress. All participants also underwent an fMRI session during which they observed neutral and negative images from the International Affective Picture System (IAPS). Our results show that scenarios simulating physical attacks can induce a freeze-like response in men. In addition, we demonstrate that while electrodermal activity (EDA), subjective stress perception, and brain activity in fMRI predict freeze-like response in men, their effect on freeze-like response is entirely dependent on the level of training and experience of a given individual.

neuroscience↗