title: Assessing interactions in the brain with exact low-resolution electromagnetic tomography.
abstract: Scalp electric potentials (electroencephalogram; EEG) are contingent to the impressed current density unleashed by cortical pyramidal neurons undergoing post-synaptic processes. EEG neuroimaging consists of estimating the cortical current density from scalp recordings. We report a solution to this inverse problem that attains exact localization: exact low-resolution brain electromagnetic tomography (eLORETA). This non-invasive method yields high time-resolution intracranial signals that can be used for assessing functional dynamic connectivity in the brain, quantified by coherence and phase synchronization. However, these measures are non-physiologically high because of volume conduction and low spatial resolution. We present a new method to solve this problem by decomposing them into instantaneous and lagged components, with the lagged part having almost pure physiological origin.
authors: The KEY Institute for Brain-Mind Research, University Hospital of Psychiatry, Lenggstrasse 31, 8032 Zurich, Switzerland. pascualm@key.uzh.ch
authors: Roberto D
authors: RD
authors: Pascual-Marqui
authors: Dietrich
authors: D
authors: Lehmann
authors: Martha
authors: M
authors: Koukkou
authors: Kieko
authors: K
authors: Kochi
authors: Peter
authors: P
authors: Anderer
authors: Bernd
authors: B
authors: Saletu
authors: Hideaki
authors: H
authors: Tanaka
authors: Koichi
authors: K
authors: Hirata
authors: E Roy
authors: ER
authors: John
authors: Leslie
authors: L
authors: Prichep
authors: Rolando
authors: R
authors: Biscay-Lirio
authors: Toshihiko
authors: T
authors: Kinoshita
mesh_terms: D001921:Brain / Q000502:physiology*; D004553:Electric Conductivity; D004569:Electroencephalography; D004574:Electromagnetic Fields; D008959:Models, Neurological; D009474:Neurons / Q000166:cytology; D014054:Tomography / Q000379:methods*