Search bioRxiv⌕ Search

Biology subjects

Tomescu, M. I.

Publications and source records attributed to Tomescu, M. I..

3 recordsLinked to original sources

EEG Microstate Dynamics During Immersive VR Earthquake Exposure: Signatures of Threat Reactivity, Recovery, and Resilience

Adapting to natural disasters requires rapid and flexible regulation of emotional and physiological responses, yet the large-scale brain dynamics supporting this process remain poorly understood. Using an immersive virtual reality (VR) earthquake simulation, we investigated real-time neural adaptation to acute environmental threat and its modulation by resilience. Seventy-six participants were randomly assigned to a VR earthquake condition (VR-ES, n = 38) or a control VR condition (VR-CTRL, n = 38). Resting-state EEG was recorded before and after the VR experience, and continuous mobile EEG was recorded during the simulation. EEG microstate analysis was used to characterize large-scale brain dynamics associated with threat exposure and recovery. Exposure to the simulated disaster induced distinct alterations in microstate dynamics, with opposing changes in microstates C (p<0.001, rb=0.55) and D (p<0.001, rb=0.52) observed specifically in the VR-ES group. Moreover, our results confirm that distinct neural patterns are activated during the recovery resting-state phase following VR-ES. Critically, resilience and childhood adversity moderated the patterns of associations with emotional recovery, such that individuals with higher resilience exhibited more adaptive microstate configurations associated with improved recovery outcomes. These findings suggest that flexible reorganization of large-scale brain states supports adaptation to acute environmental stress and that resilience shapes the neural dynamics underlying recovery. This work highlights the value of ecologically valid VR paradigms combined with mobile neurophysiology for understanding individual differences in responses to environmental threat and their adaptive neural mechanisms.

neuroscience↗

Valence-specific EEG microstate modulations during self-generated affective states

We spend a significant part of our lives navigating emotionally charged mind-wandering states by spontaneously imagining the past or the future, which predicts general well-being. We investigated brain self-generated affective states using EEG microstate analysis to identify the temporal dynamics of underlying brain networks that sustain endogenous affective state activity. With this aim, we compared the temporal dynamics of five distinct microstates between baseline resting-state, positive (e.g., awe, contentment), and negative (e.g., anger, fear) affective self-generated states. We found affect-related modulations of B, C, and D dynamics. Microstates B and D were increased, while microstate C was decreased during negative and positive valence self-generated affective states. In addition, we found valence-specific mechanisms of spontaneous affective regulation. Negative valence self-generated affective states specifically modulate the increased presence of D microstates and decreased occurrence of E microstates compared to baseline and positive valence affective states. The self-generated positive valence affective states are characterized by more prevalent B and les present A microstates compared to both baseline and negative valence affective states. These findings provide valuable insights into the neurodynamic patterns of affective regulation and implications for developing biomarkers for therapeutic interventions in mood and anxiety disorders.

neuroscience↗

Spontaneous thought and microstate activity modulation by social imitation

Social imitation increases well-being and closeness by mechanisms that remain poorly understood. We propose that imitation impacts behavioural states in part by modulating post-imitation mind-wandering. The human mind wanders spontaneously and frequently, revisiting the past and imagining the future of self and of others. External and internal factors can influence wandering spontaneous thoughts, whose content predicts subsequent emotional states. In 43 young subjects, we find that imitating the arm movements of an actor alters the dynamics and the content of subsequent resting-state spontaneous thoughts. Imitation-sensitive features of spontaneous thoughts correlate with both behavioural states and salivary oxytocin levels. EEG microstate analysis reveals that global patterns of correlated neuronal activity predict imitation-induced changes in spontaneous thoughts. Thus, imitation can modulate ongoing activity in specific neural networks to change spontaneous thought patterns as a function of oxytocin levels, and to ultimately orchestrate behavioural states.

neuroscience↗