title: Working memory and prefrontal cortex dysfunction: specificity to schizophrenia compared with major depression.
abstract: BACKGROUND
  A large number of studies suggest the presence of deficits in dorsolateral prefrontal cortex function during performance of working memory tasks in individuals with schizophrenia. However, working memory deficits may also present in other psychiatric disorders, such as major depression. It is not clear whether people with major depression also demonstrate impaired prefrontal activation during performance of working memory tasks.
  
  
  METHODS
  We used functional magnetic resonance imaging to assess the patterns of cortical activation associated with the performance of a 2-back version of the N-Back task (working memory) in 38 individuals with schizophrenia and 14 with major depression.
  
  
  RESULTS
  We found significant group differences in the activation of dorsolateral prefrontal cortex associated with working memory performance. Consistent with prior research, participants with schizophrenia failed to show activation of right dorsolateral prefrontal cortex in response to working memory tasks demands, whereas those with major depression showed clear activation of right and left dorsolateral prefrontal cortex as well as bilateral activation of inferior and superior frontal cortex.
  
  
  CONCLUSIONS
  During performance of working memory tasks, deficits in prefrontal activation, including dorsolateral regions, are more severe in participants with schizophrenia (most of whom were recently released outpatients) than in unmedicated outpatients with acute nonpsychotic major depression.
authors.affiliation: Department of Psychology, Washington University, St. Louis, Missouri, USA.
authors.forename: Deanna M
authors.initials: DM
authors.lastname: Barch
authors.forename: Yvette I
authors.initials: YI
authors.lastname: Sheline
authors.forename: John G
authors.initials: JG
authors.lastname: Csernansky
authors.forename: Abraham Z
authors.initials: AZ
authors.lastname: Snyder
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D003865:Major Depressive Disorder / Q000503:physiopathology*; D005149:Facial Expression; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008569:Memory Disorders / Q000503:physiopathology*; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D010775:Photic Stimulation; D017397:Prefrontal Cortex / Q000503:physiopathology*; D011930:Reaction Time; D012559:Schizophrenia / Q000503:physiopathology*; D013647:Task Performance and Analysis; D014706:Verbal Learning