title: Neural correlates of set-shifting: decomposing executive functions in schizophrenia.
abstract: BACKGROUND
  Although there is considerable evidence that patients with schizophrenia have impaired executive functions, the neural mechanisms underlying these deficits are unclear. Generation and selection is one of the basic mechanisms of executive functioning. We investigated the neural correlates of this mechanism by means of functional magnetic resonance imaging (fMRI) in patients with schizophrenia and healthy controls.
  
  
  METHODS
  We used the Wisconsin Card Sorting Test (WCST) in an event-related fMRI study to analyze neural activation patterns during the distinct components of the WCST in 36 patients with schizophrenia and 28 controls. We focused our analyses on the process of set-shifting. After participants received negative feedback, they had to generate and decide on a new sorting rule.
  
  
  RESULTS
  A widespread activation pattern encompassing the inferior and middle frontal gyrus, parietal, temporal and occipital cortices, anterior cingulate cortex (ACC), supplementary motor area, insula, caudate, thalamus and brainstem was observed in patients with schizophrenia after negative versus positive feedback, whereas in healthy controls, significant activation clusters were more confined to the cortical areas. Significantly increased activation in the rostral ACC after negative feedback and in the dorsal ACC during matching after negative feedback were observed in schizophrenia patients compared with controls. Controls showed activation in the bilateral dorsolateral prefrontal cortex (Brodmann area 46), whereas schizophrenia patients showed activation in the right dorsolateral prefrontal cortex only.
  
  
  CONCLUSIONS
  All patients were taking neuroleptic medication, which has an impact on cognitive function as well as on dopaminergic and serotonergic prefrontal metabolism.
  
  
  CONCLUSIONS
  Our data suggest that, in patients with schizophrenia, set-shifting is associated with increased activation in the rostral and dorsal ACC, reflecting higher emotional and cognitive demands, respectively.
authors: Department of Psychiatry, University of Muenster, Muenster, Germany.
authors: Andreas
authors: A
authors: Wilmsmeier
authors: Patricia
authors: P
authors: Ohrmann
authors: Thomas
authors: T
authors: Suslow
authors: Ansgar
authors: A
authors: Siegmund
authors: Katja
authors: K
authors: Koelkebeck
authors: Matthias
authors: M
authors: Rothermundt
authors: Harald
authors: H
authors: Kugel
authors: Volker
authors: V
authors: Arolt
authors: Jochen
authors: J
authors: Bauer
authors: Anya
authors: A
authors: Pedersen
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009474:Neurons / Q000502:physiology; D009483:Neuropsychological Tests; D012559:Schizophrenia / Q000503:physiopathology*; D012718:Set, Psychology