Intrinsic Neural Timescales Relate to Event-Related Activity - Key Role for Intracolumnar Connections.

Abstract

The relationship of the brain's intrinsic neural timescales (INTs) during the resting state with event-related activity in response to external stimuli remains poorly understood. Here, we bridge this gap by combining computational modeling with human magnetoencephalography (MEG, resting state: N=64, 45 female; task state: N=58, 41 female) data to investigate the relation of intrinsic neuronal timescales (INT) with task-related activity, e.g., event-related fields (ERFs). Using the Jansen-Rit model, we first show that intracolumnar (and thus intra-regional) excitatory and inhibitory connections (rather than inter-regional feedback, feedforward and lateral connections between the columns of different regions) strongly influence both resting state INTs and task-related ERFs. Secondly, our results demonstrate a positive relationship between the magnitude of event-related fields (mERFs) and INTs, observed in both model simulations and empirical MEG data collected during an emotional face recognition task. Thirdly, modeling shows that the positive relationship of mERF and INT depends on intracolumnar connections through observing that the correlation between them disappears for fixed values of intracolumnar connections. Together, these findings highlight the importance of intracolumnar connections as a shared biological mechanism underlying both the resting-state's INTs and the task-state's event-related activity including their interplay.Significance Statement Intrinsic neural timescales (INTs) reflect the temporal persistence of neural activity and are increasingly recognized as a fundamental property of brain dynamics. How INTs relate to event-related neural responses remains poorly understood. Bridging this gap would give us a wider perspective on rest-task relationship in the brain. In this study, we combine modeling and magnetoencephalography (MEG) data to investigate this relationship. Modeling shows that intracolumnar connectivity simultaneously modulates both resting-state INTs and task-state event-related activity, leading to a positive correlation. The positive correlation is confirmed in MEG data. By bridging the gap between resting-state dynamics and task-state event-related responses, our work advances the understanding of how spontaneous and stimulus-driven brain processes are fundamentally intertwined.