title: Magnetoencephalographic signatures of insular epileptic spikes based on functional connectivity.
abstract: Failure to recognize insular cortex seizures has recently been identified as a cause of epilepsy surgeries targeting the temporal, parietal, or frontal lobe. Such failures are partly due to the fact that current noninvasive localization techniques fare poorly in recognizing insular epileptic foci. Our group recently demonstrated that magnetoencephalography (MEG) is sensitive to epileptiform spikes generated by the insula. In this study, we assessed the potential of distributed source imaging and functional connectivity analyses to distinguish insular networks underlying the generation of spikes. Nineteen patients with operculo-insular epilepsy were investigated. Each patient underwent MEG as well as T1-weighted magnetic resonance imaging (MRI) as part of their standard presurgical evaluation. Cortical sources of MEG spikes were reconstructed with the maximum entropy on the mean algorithm, and their time courses served to analyze source functional connectivity. The results indicate that the anterior and posterior subregions of the insula have specific patterns of functional connectivity mainly involving frontal and parietal regions, respectively. In addition, while their connectivity patterns are qualitatively similar during rest and during spikes, couplings within these networks are much stronger during spikes. These results show that MEG can establish functional connectivity-based signatures that could help in the diagnosis of different subtypes of insular cortex epilepsy. Hum Brain Mapp 37:3250-3261, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Département De Génie Électrique, École Polytechnique De Montréal, Montreal, Quebec, Canada.|Research Centre, Centre Hospitalier De L'Université De Montréal (CRCHUM), Montreal, Quebec, Canada.
authors.forename: Younes
authors.initials: Y
authors.lastname: Zerouali
authors.affiliation: Département De Génie Électrique, École Polytechnique De Montréal, Montreal, Quebec, Canada.|Institut De Cardiologie De Montréal, Montreal, Quebec, Canada.
authors.forename: Philippe
authors.initials: P
authors.lastname: Pouliot
authors.affiliation: Research Centre, Centre Hospitalier De L'Université De Montréal (CRCHUM), Montreal, Quebec, Canada.
authors.forename: Manon
authors.initials: M
authors.lastname: Robert
authors.affiliation: Division of Neurology, Department of Pediatrics, IWK Health Centre, Halifax, Nova Scotia, Canada.
authors.forename: Ismail
authors.initials: I
authors.lastname: Mohamed
authors.affiliation: Research Centre, Centre Hospitalier De L'Université De Montréal (CRCHUM), Montreal, Quebec, Canada.
authors.forename: Alain
authors.initials: A
authors.lastname: Bouthillier
authors.affiliation: Département De Génie Électrique, École Polytechnique De Montréal, Montreal, Quebec, Canada.|Institut De Cardiologie De Montréal, Montreal, Quebec, Canada.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lesage
authors.affiliation: Research Centre, Centre Hospitalier De L'Université De Montréal (CRCHUM), Montreal, Quebec, Canada.|Division of Neurology, Department of Medicine, CHUM - Hôpital Notre-Dame, Montreal, Quebec, Canada.
authors.forename: Dang K
authors.initials: DK
authors.lastname: Nguyen
mesh_terms: D000293:Adolescent; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D002648:Child; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D049669:History, 16th Century; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000503:physiopathology*; D055815:Young Adult
keywords: brain disorders; brain imaging; cortical phase synchronization; epilepsies; nonparametric statistics; partial