Associations between Macro- and Microscale Functional dynamics in Focal and Generalized Epilepsies

Abstract Epilepsies are a group of neurological disorders characterized by abnormal spontaneous brain activity, involving multiscale changes in brain functional organizations. However, it is not clear to what extent the epilepsy-related perturbations of spontaneous brain activity affect multi-scale functional dynamics, that provides support for their pathological relevance. We collected an epilepsy sample including patients with temporal lobe epilepsy (TLE), and genetic generalized epilepsy with tonic-clonic seizure (GTCS), as well as healthy controls. We extracted massive temporal features of fMRI BOLD time series to characterize macroscale functional dynamics, and used a large-scale biological model to simulate microscale neuronal dynamics. We investigate whether macro- and microscale functional dynamics were diverged from epilepsies, and how these changes are linked. We observed differences in macroscale gradient of time series features were prominent in the primary network and default mode network in TLE and GTCS. Microscale neuronal dynamics was reduced in the somatomotor cortices in two subtypes, and more widely reduced in GTCS. We further demonstrated strong spatial correlations between the differences in macroscale functional dynamics gradient and microscale neuronal dynamics in epilepsies. These results emphasized the impact of microscale abnormal neuronal activity on primary network and high-order networks, suggesting a systematic abnormality of brain hierarchical organization.