Brain network integration, flexibility and quasicyclicity during task and rest

Previous studies have shown that a re-organization of the brain’s functional connectome expressed in terms of integration and segregation may play a pivotal role. However, it has been proven difficult to capture both processes within a single network-based framework. In this study we apply a hierarchical, spatiotemporally flexible network perspective onto fMRI data to track changes in integration and segregation in time. Our results show that network integration and segregation occur simultaneously in the brain. During task performance, global changes in synchronization between networks arise which are tied to the underlying temporal design of the experiment. We show that a hallmark property of the dynamics of the brain’s functional connectome is a presence of quasiperiodic patterns of network activation and deactivation, which during task performance becomes intertwined with the underlying temporal structure of the experimental paradigm. The proposed approach to study spatiotemporal changes in network reconfiguration during rest as well as task performance could be useful to identify aberrant network motifs in disease.