Reconfiguration of dynamic large-scale brain network functional connectivity in generalized tonic-clonic seizures

An increasing number of studies in patients with generalized tonic-clonic seizures (GTCS) have reported the alteration of functional connectivity (FC) in many brain networks. However, little is known about the underlying temporal variability of FC in large-scale brain functional networks in patients. Recently, dynamic FC could provide novel insight into the physiological mechanisms in the brain. Here, we recruited 63 GTCS and 65 age- and sex-matched healthy controls. Dynamic FC approaches were used to evaluate alterations in the temporal variability of FC in patients at the region- and network-levels. In addition, two kinds of brain templates (>10² and > 10³ regions) and two kinds of temporal variability FC approaches were adopted to verify the stability of the results. Patients showed increased FC variability in regions of the default mode network (DMN), ventral attention network (VAN) and motor-related areas. The DAN, VAN, and DMN illustrated enhanced FC variability at the within-network level. In addition, increased FC variabilities between networks were found between the DMN and cognition-related networks, including the VAN, dorsal attention network and frontal-parietal network in GTCS. Meanwhile, the alterations in FC variability were relatively consistent across different methods and templates. Therefore, the consistent alteration of FC variability would reflect a dynamic restructuring of the large-scale brain networks in patients with GTCS. Overly frequent information communication among cognition-related networks, especially in the DMN, might play a role in the epileptic activity and/or cognitive dysfunction in patients.