title: Working memory dysfunction in schizophrenia patients with obsessive-compulsive symptoms: an fMRI study.
abstract: BACKGROUND
  A substantial proportion of schizophrenia patients also meets DSM-IV criteria for obsessive-compulsive disorder (OCD). Schizophrenia with OCD ("schizo-obsessive") patients are characterized by distinct clinical characteristics, treatment response and prognosis. Whether schizo-obsessive patients exhibit a distinct pattern of brain activation is yet unknown. To address this question, the present functional magnetic resonance imaging (fMRI) study explicitly compared alterations in brain activation and functional connectivity (FC) underlying a working memory deficit in schizophrenia patients with and without OCD.
  
  
  METHODS
  fMRI was applied during the N-back working memory (WM) task in three groups: schizo-obsessive (n=16), schizophrenia (n=17) and matched healthy volunteers (n=20). WM-related activation in the right dorsolateral prefrontal cortex (DLPFC) and the right caudate nucleus, brain areas relevant to schizophrenia and OCD, and FC analysis were used for the evaluation.
  
  
  RESULTS
  The two schizophrenia groups with and without OCD exhibited a similar reduction in activation in the right DLPFC and right caudate, as well as decreased FC compared to the healthy controls. Notably, reduced regional brain activation was not related to severity of schizophrenic or OCD symptoms.
  
  
  CONCLUSIONS
  Schizo-obsessive patients do not differ from their non-OCD schizophrenia counterparts in brain activation patterns during the N-back WM task. Cognitive paradigms taping alternative neural networks (e.g., orbitofrontal cortex) particularly relevant to OCD, are warranted in the search for potential distinctive brain activation patterns of the schizo-obsessive subgroup.
authors.affiliation: Functional Brain Imaging Unit, Wohl Institute for Advanced Imaging, Tel-Aviv Sourasky Medical Center, 6, Weizmann Street, 64239 Tel-Aviv, Israel. Electronic address: maya44@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Bleich-Cohen
authors.affiliation: Functional Brain Imaging Unit, Wohl Institute for Advanced Imaging, Tel-Aviv Sourasky Medical Center, 6, Weizmann Street, 64239 Tel-Aviv, Israel; Psychology Department, Tel-Aviv University, Tel-Aviv, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
authors.forename: T
authors.initials: T
authors.lastname: Hendler
authors.affiliation: Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Ambulatory Division, Mental health Department, Ramat-Hen, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Weizman
authors.affiliation: Research Unit, Tirat Carmel Mental Health Center, Tirat Carmel, Haifa, Israel.
authors.forename: S
authors.initials: S
authors.lastname: Faragian
authors.affiliation: Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Research Unit, Geha Psychiatric Hospital, Geha, Israel; Felsenstein Medical Research Center, Petah Tiqva, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Weizman
authors.affiliation: Research Unit, Tirat Carmel Mental Health Center, Tirat Carmel, Haifa, Israel; Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Poyurovsky
mesh_terms: D000328:Adult; D002421:Caudate Nucleus / Q000503:physiopathology*; D015897:Comorbidity; D063132:Connectome / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009771:Obsessive-Compulsive Disorder / Q000453:epidemiology / Q000503:physiopathology*; D017397:Prefrontal Cortex / Q000503:physiopathology*; D012559:Schizophrenia / Q000453:epidemiology / Q000503:physiopathology*; D055815:Young Adult
keywords: DLPFC; FMRI; N-back; Schizophrenia; Working memory