1 Multimodal Functional Imaging Lab, Department of Biomedical Engineering, McGill University, Duff Medical Building, 3775 Rue University, Montreal, QC H3A 2B4, Canada; Montreal Neurological Institute, McGill University, 3801 Rue University, Montreal, QC H3A 2B4, Canada. Electronic address: kangjoo.lee@mail.mcgill.ca.
2 Montreal Neurological Institute, McGill University, 3801 Rue University, Montreal, QC H3A 2B4, Canada; Department of Neurosurgery, Osaka University, 2-2 Yamadaoka, Suita, Osaka Prefecture, 565-0871, Japan.
3 École de Technologie Supérieure, 1100 Rue Notre-Dame O, Montreal, QC H3C 1K3, Canada; Centre de Recherches Mathématiques, Université de Montréal, Pavillon André-Aisenstadt 2920 Chemin de la tour, Montreal, QC H3T 1J4, Canada.
4 Montreal Neurological Institute, McGill University, 3801 Rue University, Montreal, QC H3A 2B4, Canada.
5 Multimodal Functional Imaging Lab, Department of Biomedical Engineering, McGill University, Duff Medical Building, 3775 Rue University, Montreal, QC H3A 2B4, Canada; Montreal Neurological Institute, McGill University, 3801 Rue University, Montreal, QC H3A 2B4, Canada; Centre de Recherches Mathématiques, Université de Montréal, Pavillon André-Aisenstadt 2920 Chemin de la tour, Montreal, QC H3T 1J4, Canada; Department of Physics and PERFORM Centre, Concordia University, 7200 Rue Sherbrooke St. W, Montreal, QC H4B 1R6, Canada.

Disruption, emergence and lateralization of brain network hubs in mesial temporal lobe epilepsy.

Neuroimage Clin. 2018;20:71-84

Authors: Lee K, Khoo HM, Lina JM, Dubeau F, Gotman J, Grova C

Abstract

Hubs of brain networks are brain regions exhibiting denser connections than others, promoting long-range communication. Studies suggested the reorganization of hubs in epilepsy. The patterns of connector hub abnormalities specific to mesial temporal lobe epilepsy (mTLE) are unclear. We wish to quantify connector hub abnormalities in mTLE and identify epilepsy-related resting state networks involving abnormal connector hubs. A recently developed sparsity-based analysis of reliable k-hubness (SPARK) allowed us to address this question by using resting state functional MRI in 20 mTLE patients and 17 healthy controls. Handling the multicollinearity of functional networks, SPARK measures a new metric of hubness by counting the number (k) of networks involved in each voxel, and identifies which networks are actually associated to each connector hub. This measure provides new information about the network architecture involving connector hubs and a realistic range of k-hubness. We quantified the disruption and emergence of connector hubs in individual epileptic subjects and assessed the lateralization of networks involving connector hubs. In mTLE, we found pathological disruptions of normal connector hubs in the mTL and within the default mode network. Right mTLE had remarkably higher emergence of new connector hubs in the mTL than left mTLE. Different patterns of lateralization of the salience network involving the abnormal hippocampus were found in right versus left mTLE. The temporal, cerebellar, default mode, subcortical and motor networks also contributed to the lateralization of hippocampal networks. We finally observed an asymmetrical connector hub reorganization and overall regularization of epilepsy-related resting state networks in mTLE, characterized by the disruption of distant connections and the emergence of local connections.

PMID: 30094158 [PubMed - indexed for MEDLINE]