Hierarchical reorganization of brain functional networks in mesial temporal lobe epilepsy

Mesial temporal lobe epilepsy (mTLE) is a common recurrent neurological disorder, which timely surgical intervention is often required in drug-resistant cases. Although previous neuroimaging studies have explored brain abnormalities associated with mTLE, the alterations in brain network functional activities remain far from be elucidated.

Preoperative resting-state fMRI data were collected from 47 patients with drug-resistant mTLE, divided into 2 groups based on postoperative outcomes. Data from 32 age- and sex-matched healthy controls (HC) were included for comparison. Gradient analysis was used to investigate the changes in the hierarchy of brain networks in mTLE patients.

Both SF and NSF groups exhibited disruptions in principal gradient organization compared to HC. Significant differences in gradient scores were observed between the SF and NSF groups, particularly within the default mode network (DMN) and somatomotor network (SMN). In the DMN, significant differences were observed in regions such as the left middle temporal gyrus and the left inferior temporal gyrus. In the SMN, significant differences were found in regions such as the right precentral gyrus and the right postcentral gyrus.

Alterations in brain networks hierarchy within the SMN and DMN may reflect distinct patterns of network reorganization associated with postoperative seizure outcomes, which provide new insights into prognosis and therapeutic strategies in mTLE.