title: Assessing human brain impedance using simultaneous surface and intracerebral recordings.
abstract: Most of the literature on the brain impedance proposes a frequency-independent resistive model. Recently, this conclusion was tackled by a series of papers (Bédard et al., 2006; Bédard and Destexhe, 2009; Gomes et al., 2016), based on microscopic sale modeling and measurements. Our paper aims to investigate the impedance issue using simultaneous in vivo depth and surface signals recorded during intracerebral electrical stimulation of epileptic patients, involving a priori different tissues with different impedances. Our results confirm the conclusions from Logothethis et al. (2007): there is no evidence of frequency dependence of the brain tissue impedance (more precisely, there is no difference, in terms of frequency filtering, between the brain and the skull bone), at least at a macroscopic scale. In order to conciliate findings from both microscopic and macroscopic scales, we recall different neural/synaptic current generators' models from the literature and we propose an original computational model, based on fractional dynamics.
authors.affiliation: Université de Lorraine, CRAN, UMR 7039, 2 av. de la Forêt de Haye, 54500 Vandoeuvre-lés-Nancy, France; CNRS, CRAN, UMR 7039, France. Electronic address: radu.ranta@univ-lorraine.fr.
authors.forename: Radu
authors.initials: R
authors.lastname: Ranta
authors.affiliation: Université de Lorraine, CRAN, UMR 7039, 2 av. de la Forêt de Haye, 54500 Vandoeuvre-lés-Nancy, France; CNRS, CRAN, UMR 7039, France.
authors.forename: Steven
authors.initials: S
authors.lastname: Le Cam
authors.affiliation: Université de Lorraine, CRAN, UMR 7039, 2 av. de la Forêt de Haye, 54500 Vandoeuvre-lés-Nancy, France; CNRS, CRAN, UMR 7039, France; CHU Nancy, Neurology Department, 54000 Nancy, France.
authors.forename: Louise
authors.initials: L
authors.lastname: Tyvaert
authors.affiliation: Université de Lorraine, CRAN, UMR 7039, 2 av. de la Forêt de Haye, 54500 Vandoeuvre-lés-Nancy, France; CNRS, CRAN, UMR 7039, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Louis-Dorr
mesh_terms: D001921:Brain / Q000502:physiology* / Q000503:physiopathology; D003198:Computer Simulation; D000069279:Drug Resistant Epilepsy / Q000503:physiopathology; D017097:Electric Impedance; D004558:Electric Stimulation; D004569:Electroencephalography; D006801:Humans; D058542:Implantable Neurostimulators; D008959:Models, Neurological; D013569:Synapses / Q000502:physiology
keywords: brain impedance; computational current source models; intracerebral stimulation; simultaneous EEG–SEEG