Functional Importance Backbones of the Brain at Rest, Wakefulness, and Sleep.
Brain Sciences July 20, 2025 Klaus Lehnertz, Timo Bröhl
The brain remains active even without external tasks, organizing into resting-state networks that shape internal thoughts. While prior work mapped these networks and the roles of individual brain regions, the time-dependent importance of functional interactions between regions was unexplored. This study analyzed long-term EEG recordings from over 100 participants, using centrality to track the evolving importance of both brain regions and their connections. Results show that resting-state network architecture is critically shaped by dynamic interplay between regions. The authors identified "functional importance backbones"—core sets of dynamically central vertices and edges—whose configuration varies between subgroups and across brain states like wakefulness and sleep. Regions of the default mode network exhibited adaptable centrality patterns, challenging the idea of static network cores.