title: Subregional Mesiotemporal Network Topology Is Altered in Temporal Lobe Epilepsy.
abstract: Temporal lobe epilepsy (TLE) is the most frequent drug-resistant epilepsy in adults and commonly associated with variable degrees of mesiotemporal atrophy on magnetic resonance imaging (MRI). Analyses of inter-regional connectivity have unveiled disruptions in large-scale cortico-cortical networks; little is known about the topological organization of the mesiotemporal lobe, the limbic subnetwork central to the disorder. We generated covariance networks based on high-resolution MRI surface-shape descriptors of the hippocampus, entorhinal cortex, and amygdala in 134 TLE patients and 45 age- and sex-matched controls. Graph-theoretical analysis revealed increased path length and clustering in patients, suggesting a shift toward a more regularized arrangement; findings were reproducible after split-half assessment and across 2 parcellation schemes. Analysis of inter-regional correlations and module participation showed increased within-structure covariance, but decreases between structures, particularly with regards to the hippocampus and amygdala. While higher clustering possibly reflects topological consequences of axonal sprouting, decreases in interstructure covariance may be a consequence of disconnection within limbic circuitry. Preoperative network parameters, specifically the segregation of the ipsilateral hippocampus, predicted long-term seizure freedom after surgery.
authors.affiliation: Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, McGill University, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada Deparment of Social Neuroscience, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
authors.forename: Boris C
authors.initials: BC
authors.lastname: Bernhardt
authors.affiliation: Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, McGill University, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada.
authors.forename: Neda
authors.initials: N
authors.lastname: Bernasconi
authors.affiliation: Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, McGill University, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada.
authors.forename: Seok-Jun
authors.initials: SJ
authors.lastname: Hong
authors.affiliation: Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, McGill University, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Dery
authors.affiliation: Neuroimaging of Epilepsy Laboratory, McConnell Brain Imaging Center, McGill University, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bernasconi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000679:Amygdala / Q000000981:diagnostic imaging* / Q000601:surgery; D000069279:Drug Resistant Epilepsy / Q000000981:diagnostic imaging* / Q000601:surgery; D018728:Entorhinal Cortex / Q000000981:diagnostic imaging* / Q000601:surgery; D004833:Epilepsy, Temporal Lobe / Q000000981:diagnostic imaging* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality; D006624:Hippocampus / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult
keywords: MRI; connectivity; epilepsy; graph theory; temporal lobe