title: Functionally aberrant electrophysiological cortical connectivities in first episode medication-naive schizophrenics from three psychiatry centers.
abstract: Functional dissociation between brain processes is widely hypothesized to account for aberrations of thought and emotions in schizophrenic patients. The typically small groups of analyzed schizophrenic patients yielded different neurophysiological findings, probably because small patient groups are likely to comprise different schizophrenia subtypes. We analyzed multichannel eyes-closed resting EEG from three small groups of acutely ill, first episode productive schizophrenic patients before start of medication (from three centers: Bern N = 9; Osaka N = 9; Berlin N = 12) and their controls. Low resolution brain electromagnetic tomography (LORETA) was used to compute intracortical source model-based lagged functional connectivity not biased by volume conduction effects between 19 cortical regions of interest (ROIs). The connectivities were compared between controls and patients of each group. Conjunction analysis determined six aberrant cortical functional connectivities that were the same in the three patient groups. Four of these six concerned the facilitating EEG alpha-1 frequency activity; they were decreased in the patients. Another two of these six connectivities concerned the inhibiting EEG delta frequency activity; they were increased in the patients. The principal orientation of the six aberrant cortical functional connectivities was sagittal; five of them involved both hemispheres. In sum, activity in the posterior brain areas of preprocessing functions and the anterior brain areas of evaluation and behavior control functions were compromised by either decreased coupled activation or increased coupled inhibition, common across schizophrenia subtypes in the three patient groups. These results of the analyzed three independent groups of schizophrenics support the concept of functional dissociation.
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, The KEY Institute for Brain-Mind Research, University Hospital for Psychiatry Zurich, Switzerland.
authors.forename: Dietrich
authors.initials: D
authors.lastname: Lehmann
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, The KEY Institute for Brain-Mind Research, University Hospital for Psychiatry Zurich, Switzerland.
authors.forename: Pascal L
authors.initials: PL
authors.lastname: Faber
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, The KEY Institute for Brain-Mind Research, University Hospital for Psychiatry Zurich, Switzerland.
authors.forename: Roberto D
authors.initials: RD
authors.lastname: Pascual-Marqui
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, The KEY Institute for Brain-Mind Research, University Hospital for Psychiatry Zurich, Switzerland.
authors.forename: Patricia
authors.initials: P
authors.lastname: Milz
authors.affiliation: Laboratory of Clinical Psychophysiology, Department of Psychiatry, University Hospital Benjamin Franklin, Free University of Berlin Berlin, Germany.
authors.forename: Werner M
authors.initials: WM
authors.lastname: Herrmann
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, The KEY Institute for Brain-Mind Research, University Hospital for Psychiatry Zurich, Switzerland.
authors.forename: Martha
authors.initials: M
authors.lastname: Koukkou
authors.affiliation: Saito Mental Clinic Osaka, Japan.
authors.forename: Naomi
authors.initials: N
authors.lastname: Saito
authors.affiliation: Experimental and Clinical Research Center, Charité - University Medicine Berlin Berlin, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Winterer
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, The KEY Institute for Brain-Mind Research, University Hospital for Psychiatry Zurich, Switzerland.
authors.forename: Kieko
authors.initials: K
authors.lastname: Kochi
keywords: EEG; LORETA; cortical source modeling; electrical source imaging; functional connectivity; functional dissociation; schizophrenia subtypes