title: Abnormal Brain Areas Common to the Focal Epilepsies: Multivariate Pattern Analysis of fMRI.
abstract: Individuals with focal epilepsy have heterogeneous sites of seizure origin. However, there may be brain regions that are common to most cases of intractable focal epilepsy. In this study, we aim to identify these using multivariate analysis of task-free functional MRI. Fourteen subjects with extratemporal focal epilepsy and 14 healthy controls were included in the study. Task-free functional MRI data were used to calculate voxel-wise regional connectivity with regional homogeneity (ReHo) and weighted degree centrality (DCw), in addition to regional activity using fraction of amplitude of low-frequency fluctuations (fALFF). Multivariate pattern analysis was applied to each of these metrics to discriminate brain areas that differed between focal epilepsy subjects and healthy controls. ReHo and DCw classified focal epilepsy subjects from healthy controls with high accuracy (89.3% and 75%, respectively). However, fALFF did not significantly classify patients from controls. Increased regional network activity in epilepsy subjects was seen in the ipsilateral piriform cortex, insula, and thalamus, in addition to the dorsal anterior cingulate cortex and lateral frontal cortices. Decreased regional connectivity was observed in the ventromedial prefrontal cortex, as well as lateral temporal cortices. Patients with extratemporal focal epilepsy have common areas of abnormality (ReHo and DCw measures), including the ipsilateral piriform cortex, temporal neocortex, and ventromedial prefrontal cortex. ReHo shows additional increase in the "salience network" that includes anterior insula and anterior cingulate cortex. DCw showed additional effects in the ipsilateral thalamus and striatum. These brain areas may represent key regional network properties underlying focal epilepsy.
authors.affiliation: 1 The Florey Institute of Neuroscience and Mental Health , Austin Campus, Melbourne, Australia .|2 The University of Melbourne , Florey Department of Neuroscience and Mental Health, Melbourne, Australia .
authors.forename: Mangor
authors.initials: M
authors.lastname: Pedersen
authors.affiliation: 1 The Florey Institute of Neuroscience and Mental Health , Austin Campus, Melbourne, Australia .
authors.forename: Evan K
authors.initials: EK
authors.lastname: Curwood
authors.affiliation: 1 The Florey Institute of Neuroscience and Mental Health , Austin Campus, Melbourne, Australia .|2 The University of Melbourne , Florey Department of Neuroscience and Mental Health, Melbourne, Australia .|3 Department of Neurology, Austin Health , Melbourne, Australia .
authors.forename: David N
authors.initials: DN
authors.lastname: Vaughan
authors.affiliation: 1 The Florey Institute of Neuroscience and Mental Health , Austin Campus, Melbourne, Australia .|2 The University of Melbourne , Florey Department of Neuroscience and Mental Health, Melbourne, Australia .
authors.forename: Amir H
authors.initials: AH
authors.lastname: Omidvarnia
authors.affiliation: 1 The Florey Institute of Neuroscience and Mental Health , Austin Campus, Melbourne, Australia .|2 The University of Melbourne , Florey Department of Neuroscience and Mental Health, Melbourne, Australia .|3 Department of Neurology, Austin Health , Melbourne, Australia .
authors.forename: Graeme D
authors.initials: GD
authors.lastname: Jackson
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000473:pathology; D063132:Connectome; D004828:Epilepsies, Partial / Q000000981:diagnostic imaging / Q000473:pathology*; D004827:Epilepsy / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006624:Hippocampus / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D015999:Multivariate Analysis; D009415:Nerve Net / Q000000981:diagnostic imaging / Q000473:pathology
keywords: connectomics; extratemporal; focal epilepsy; functional connectivity; functional magnetic resonance imaging; multivariate pattern analysis