title: Coupling between gamma-band power and cerebral blood volume during recurrent acute neocortical seizures.
abstract: Characterization of neural and hemodynamic biomarkers of epileptic activity that can be measured using non-invasive techniques is fundamental to the accurate identification of the epileptogenic zone (EZ) in the clinical setting. Recently, oscillations at gamma-band frequencies and above (>30 Hz) have been suggested to provide valuable localizing information of the EZ and track cortical activation associated with epileptogenic processes. Although a tight coupling between gamma-band activity and hemodynamic-based signals has been consistently demonstrated in non-pathological conditions, very little is known about whether such a relationship is maintained in epilepsy and the laminar etiology of these signals. Confirmation of this relationship may elucidate the underpinnings of perfusion-based signals in epilepsy and the potential value of localizing the EZ using hemodynamic correlates of pathological rhythms. Here, we use concurrent multi-depth electrophysiology and 2-dimensional optical imaging spectroscopy to examine the coupling between multi-band neural activity and cerebral blood volume (CBV) during recurrent acute focal neocortical seizures in the urethane-anesthetized rat. We show a powerful correlation between gamma-band power (25-90 Hz) and CBV across cortical laminae, in particular layer 5, and a close association between gamma measures and multi-unit activity (MUA). Our findings provide insights into the laminar electrophysiological basis of perfusion-based imaging signals in the epileptic state and may have implications for further research using non-invasive multi-modal techniques to localize epileptogenic tissue.
authors.affiliation: Department of Psychology, University of Sheffield, Sheffield S10 2TN, UK; Department of Neurological Surgery, Neurology and Neuroscience, Brain and Mind Research Institute, Brain and Spine Center, Weill Cornell Medical College, New York Presbyterian Hospital, 525 East 68th Street, Box 99, New York, NY 10021, USA. Electronic address: sam.harris@sheffield.ac.uk.
authors.forename: Sam
authors.initials: S
authors.lastname: Harris
authors.affiliation: Department of Neurological Surgery, Neurology and Neuroscience, Brain and Mind Research Institute, Brain and Spine Center, Weill Cornell Medical College, New York Presbyterian Hospital, 525 East 68th Street, Box 99, New York, NY 10021, USA.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Ma
authors.affiliation: Department of Neurological Surgery, Neurology and Neuroscience, Brain and Mind Research Institute, Brain and Spine Center, Weill Cornell Medical College, New York Presbyterian Hospital, 525 East 68th Street, Box 99, New York, NY 10021, USA.
authors.forename: Mingrui
authors.initials: M
authors.lastname: Zhao
authors.affiliation: Department of Psychology, University of Sheffield, Sheffield S10 2TN, UK.
authors.forename: Luke
authors.initials: L
authors.lastname: Boorman
authors.affiliation: School of Systems Engineering, University of Reading, Reading RG6 6AH, UK.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Psychology, University of Sheffield, Sheffield S10 2TN, UK.
authors.forename: Aneurin
authors.initials: A
authors.lastname: Kennerley
authors.affiliation: Department of Psychology, University of Sheffield, Sheffield S10 2TN, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Bruyns-Haylett
authors.affiliation: Department of Psychology, University of Sheffield, Sheffield S10 2TN, UK.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Overton
authors.affiliation: Department of Psychology, University of Sheffield, Sheffield S10 2TN, UK.
authors.forename: Jason
authors.initials: J
authors.lastname: Berwick
authors.affiliation: Department of Neurological Surgery, Neurology and Neuroscience, Brain and Mind Research Institute, Brain and Spine Center, Weill Cornell Medical College, New York Presbyterian Hospital, 525 East 68th Street, Box 99, New York, NY 10021, USA.
authors.forename: Theodore H
authors.initials: TH
authors.lastname: Schwartz
mesh_terms: D015761:4-Aminopyridine; D000818:Animals; D001810:Blood Volume / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003292:Convulsants; D004569:Electroencephalography; D005260:Female; D065818:Gamma Rhythm; D019579:Neocortex / Q000503:physiopathology*; D061848:Optical Imaging; D051381:Rats; D012008:Recurrence; D012640:Seizures / Q000139:chemically induced / Q000503:physiopathology*
chemical_list: D003292:Convulsants; D015761:4-Aminopyridine
keywords: 4-AP; Focal epilepsy; Gamma; Neurovascular coupling
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