Abstract
BACKGROUND AND PURPOSE: Although most studies on epilepsy have focused on the epileptogenic zone, epilepsy is a system-level disease characterized by aberrant neuronal synchronization among groups of neurons. Increasingly, studies have indicated that mesial temporal lobe epilepsy may be a network-level disease; however, few investigations have examined resting-state functional connectivity of the entire brain, particularly in patients with mesial temporal lobe epilepsy and hippocampal sclerosis. This study primarily investigated whole-brain resting-state functional connectivity abnormality in patients with mesial temporal lobe epilepsy and right hippocampal sclerosis during the interictal period.
MATERIALS AND METHODS: We investigated resting-state functional connectivity of 21 patients with mesial temporal lobe epilepsy with right hippocampal sclerosis and 21 neurologically healthy controls. A multivariate pattern analysis was used to identify the functional connections that most clearly differentiated patients with mesial temporal lobe epilepsy with right hippocampal sclerosis from controls.
RESULTS: Discriminative analysis of functional connections indicated that the patients with mesial temporal lobe epilepsy with right hippocampal sclerosis exhibited decreased resting-state functional connectivity within the right hemisphere and increased resting-state functional connectivity within the left hemisphere. Resting-state network analysis suggested that the internetwork connections typically obey the hemispheric lateralization trend and most of the functional connections that disturb the lateralization trend are the intranetwork ones.
CONCLUSIONS: The current findings suggest that weakening of the resting-state functional connectivity associated with the right hemisphere appears to strengthen resting-state functional connectivity on the contralateral side, which may be related to the seizure-induced damage and underlying compensatory mechanisms. Resting-state network–based analysis indicated that the compensatory mechanism among different resting-state networks may disturb the hemispheric lateralization.
Abbreviations
- DMN
- default-mode network
- FC
- functional connectivity or connection
- HS
- hippocampal sclerosis
- mTLE
- mesial temporal lobe epilepsy
- R-mTLE
- mesial temporal lobe epilepsy with right hippocampal sclerosis
- RS
- resting-state
- RSN
- resting-state network
- TLE
- temporal lobe epilepsy
- © 2015 American Society of Neuroradiology
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