title: Lateralization of cerebral hemodynamics during Wisconsin Card Sorting Test: a functional transcranial Doppler sonography study.
abstract: OBJECTIVE
  Studies on lateralization of cerebral metabolism during Wisconsin Card Sorting Test (WCST), a well-known paradigm of category learning, have shown mixed results. Moreover, sorting dimension (number, color and shape) is a cofounder of laterality in WCST. Functional transcranial Doppler sonography (fTCD) has a high temporal resolution and allows the measurement of mean cerebral blood flow velocity (CBFV) in the middle (MCA) and anterior cerebral arteries (ACA), which supply lateral and medial parts of the frontal and parietal lobes, respectively. We used fTCD to investigate CBFV changes occurring in both MCA and ACA during WCST and different sorting dimensions.
  
  
  METHODS
  Twenty-one subjects underwent twice two distinct phases of the WCST, namely maintaining a rule (maintaining set) and searching for a new rule (set shifting), during bilateral fTCD of the MCA and ACA.
  
  
  RESULTS
  There was a left-sided dominance of CBFV during maintaining set and set shifting in the MCA. CBFV was not associated with test performance. The sorting dimension number caused the highest CBFV increase in both MCA and ACA during maintaining set, and the sorting dimension shape caused lowest CBFV decrease in both MCA during set shifting.
  
  
  CONCLUSIONS
  This study confirms results that cerebral blood flow (CBF) lateralizes to the left side during WCST. The 3 sorting dimensions provoked distinct processing speed during maintaining set and set shifting, but caused no effect on hemispheric lateralization.
  
  
  CONCLUSIONS
  Functional transcranial Doppler sonography can be used to assess CBFV during WCST and different sorting dimensions, and the latter modulate reaction time and cerebral hemodynamics.
authors.affiliation: Psychiatric University Hospital, Zurich, Switzerland. daniel.schuepbach@puk.zh.ch
authors.forename: Daniel
authors.initials: D
authors.lastname: Schuepbach
authors.forename: Daniel
authors.initials: D
authors.lastname: Hell
authors.forename: Ralf W
authors.initials: RW
authors.lastname: Baumgartner
mesh_terms: D000328:Adult; D020771:Anterior Cerebral Artery / Q000000981:diagnostic imaging / Q000502:physiology; D001783:Blood Flow Velocity / Q000502:physiology; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006439:Hemodynamics; D006801:Humans; D007858:Learning / Q000502:physiology*; D008297:Male; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000502:physiology; D009483:Neuropsychological Tests; D011930:Reaction Time; D017585:Ultrasonography, Doppler, Transcranial