Functional Brain Network Reorganization in Temporal Lobe Epilepsy with Hippocampal Sclerosis

INTRODUCTION: Temporal lobe epilepsy with hippocampal sclerosis (TLE-HS) involves functional abnormalities extending beyond the temporal lobe. We characterized functional network connectivity (FNC) in unilateral TLE-HS using a normative network template. METHODS: Eighty-eight adults with TLE-HS and 68 healthy controls underwent resting-state fMRI (3T Philips Achieva; TR=3 s; 209 volumes). After DPABI preprocessing, spatially constrained ICA was performed using 105 NeuroMark 2.2 networks. FNC was estimated by Pearson correlation with Fisher z transformation. Group differences across 5,460 network pairs were tested using independent-samples t-tests with FDR correction (p<0.05); effect sizes were assessed with Cohen's d. RESULTS: TLE-HS showed altered FNC in 183 network pairs (3.35%; |d|=0.73–0.88), with increased connectivity between cerebellar-visual, prefrontal-default mode, and parietal-limbic/sensorimotor networks, and decreased connectivity between sensorimotor-cognitive temporal, visual, and cerebellar-prefrontal networks. CONCLUSION: TLE-HS is characterized by distributed functional network reorganization, with concurrent hyper- and hypoconnectivity extending beyond mesial temporal structures.