Regional cerebral blood flow in Down syndrome adults during the Wisconsin Card Sorting Test: exploring cognitive activation in the context of poor performance.
BACKGROUND
Prior studies have indicated abnormal frontal lobes in Down syndrome (DS). The Wisconsin Card Sorting Test (WCST) has been used during functional brain imaging studies to activate the prefrontal cortex. Whether this activation is dependent on successful performance remains unclear. To determine frontal lobe regional cerebral blood flow (rCBF) response in DS and to further understand the effect of performance on rCBF during the WCST, we studied DS adults who perform poorly on this task.


METHODS
Initial slope (IS), an rCBF index, was measured with the 133Xe inhalation technique during a Numbers Matching Control Task and the WCST. Ten healthy DS subjects (mean age 28.3 years) and 20 sex-matched healthy volunteers (mean age 28.7 years) were examined.


RESULTS
Performance of DS subjects was markedly impaired compared to controls. Both DS and control subjects significantly increased prefrontal IS indices compared to the control task during the WCST.


CONCLUSIONS
Prefrontal activation in DS during the WCST was not related to performance of that task, but may reflect engagement of some components involved in the task, such as effort. Further, these results show that failure to activate prefrontal cortex during WCST in schizophrenia is unlikely to be due to poor performance alone.
D000328:Adult; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology; D001931:Brain Mapping; D002560:Cerebrovascular Circulation; D003071:Cognition / Q000502:physiology*; D004314:Down Syndrome / Q000378:metabolism* / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D013647:Task Performance and Analysis; D014980:Xenon Radioisotopes