Dynamic Functional Connectivity Resolves Brain Integration-Segregation Trade-off Under Costly Links
Dynamic functional connectivity (dFC) is ubiquitously observed in the brain, but why functional networks should remain dynamic even at rest is unclear. We asked whether temporal reconfiguration becomes advantageous when keeping a functional link active is costly. Modeling resting-state dFC as a temporal communication network, we show that empirical dFC outperforms equal-cost static architectures by increasing the reach and speed of information spreading in sparse regimes. Unlike more randomized temporal null models, however, it also preserves strong local cohesiveness, temporal clustering, rapid return of information to its source, and high neighborhood retention. Empirical dFC therefore achieves a compromise between large-scale integration and transient local segregation. This compromise is not explained by generic temporal variability, nor by partially frozen null models with persistent templates. A connectome-based mean-field model reproduces several key features, including high spatial and temporal clustering and strong integrative and segregative performance, but remains more stable over time than the empirical data. Our results indicate that empirical dFC reflects a structured regime of controlled persistence and renewal, in which local neighborhoods are maintained long enough to support transient recirculation before broader network-wide spreading occurs. Dynamic functional connectivity thus appears to be a resource-efficient solution to competing communication demands.