Large-scale brain networks are distinctly affected in right and left mesial temporal lobe epilepsy

Brunno Machado de Campos, Ana Carolina Coan, Clarissa Lin Yasuda, Raphael Fernandes Casseb, Fernando Cendes
2016 Human Brain Mapping  
Mesial temporal lobe epilepsy (MTLE) with hippocampus sclerosis (HS) is associated with functional and structural alterations extending beyond the temporal regions and abnormal pattern of brain resting state networks (RSNs) connectivity. We hypothesized that the interaction of large-scale RSNs is differently affected in patients with right-and left-MTLE with HS compared to controls. We aimed to determine and characterize these alterations through the analysis of 12 RSNs, functionally parceled
more » ... 70 regions of interest (ROIs), from resting-state functional-MRIs of 99 subjects (52 controls, 26 right-and 21 left-MTLE patients with HS). Image preprocessing and statistical analysis were performed using UF 2 C-toolbox, which provided ROI-wise results for intranetwork and internetwork connectivity. Intranetwork abnormalities were observed in the dorsal default mode network (DMN) in both groups of patients and in the posterior salience network in right-MTLE. Both groups showed abnormal correlation between the dorsal-DMN and the posterior salience, as well as between the dorsal-DMN and the executive-control network. Patients with left-MTLE also showed reduced correlation between the dorsal-DMN and visuospatial network and increased correlation between bilateral thalamus and the posterior salience network. The ipsilateral hippocampus stood out as a central area of abnormalities. Alterations on left-MTLE expressed a low cluster coefficient, whereas the altered connections on right-MTLE showed low cluster coefficient in the DMN but high in the posterior salience regions. Both right-and left-MTLE patients with HS have widespread abnormal interactions of largescale brain networks; however, all parameters evaluated indicate that left-MTLE has a more intricate bihemispheric dysfunction compared to right-MTLE. Hum Brain Mapp 37:3137-3152, 2016. V C 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.
doi:10.1002/hbm.23231 pmid:27133613 pmcid:PMC5074272 fatcat:zebyqfijofaxvigqfnsax2gqka