title: Toward a better understanding of the pathophysiology of OCD SSRI responders: QEEG source localization.
abstract: OBJECTIVE
  To demonstrate the utility of three-dimensional source localization of the scalp-recorded electroencephalogram (EEG) for the identification of the most probable underlying brain dysfunction in patients with obsessive-compulsive disorder (OCD).
  
  
  METHODS
  Eyes-closed resting EEG data was recorded from the scalp locations of the International 10/20 System. Variable resolution electromagnetic tomography (VARETA) was applied to artifact-free EEG data. This mathematical algorithm estimates the source generators of EEG recorded from the scalp.
  
  
  RESULTS
  An excess in the alpha range was found with sources in the corpus striatum, in the orbito-frontal and temporo-frontal regions in untreated OCD patients. This abnormality was seen to decrease following successful treatment with paroxetine.
  
  
  CONCLUSIONS
  The VARETA findings of an activation/deactivation pattern in cortical and subcortical structures in paroxetine-responsive patients are in good accordance with data obtained in previously published positron emission tomography studies related to current hypotheses of a thalamo-striatal-frontal feedback loop being relevant for understanding the pathophysiology of OCD.
authors.affiliation: Department of Psychiatry, The Neuroscience Center, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark. bolwigtg@rh.dk
authors.forename: T G
authors.initials: TG
authors.lastname: Bolwig
authors.forename: E S
authors.initials: ES
authors.lastname: Hansen
authors.forename: A
authors.initials: A
authors.lastname: Hansen
authors.forename: H
authors.initials: H
authors.lastname: Merkin
authors.forename: L S
authors.initials: LS
authors.lastname: Prichep
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping / Q000295:instrumentation; D003342:Corpus Striatum / Q000503:physiopathology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004569:Electroencephalography; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D006801:Humans; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000188:drug therapy* / Q000503:physiopathology*; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use*; D013788:Thalamus / Q000503:physiopathology
chemical_list: D017367:Selective Serotonin Reuptake Inhibitors