Wisconsin card sorting revisited: Distinct neural circuits participating in different stages of the task identified by event-related functional magnetic resonance imaging

The Wisconsin Card Sorting Task (WCST) has been used to assess dysfunction of the prefrontal cortex and basal ganglia. Previous brain imaging studies have focused on identifying activity related to the set-shifting requiremen t of the WCST The present study used event-related functional magnetic reso nance imaging (fMRI) to study the pattern of activation during four distinc t stages in the performance of this task. Eleven subjects were scanned whil e performing the WCST and a control task involving matching two identical c ards. The results demonstrated specific involvement of different prefrontal areas during different stages of task performance. The mid-dorsolateral pr efrontal cortex (area 9/46) increased activity while subjects received eith er positive or negative feedback, that is at the point when the current inf ormation must be related to earlier events stored in working memory. This i s consistent with the proposed role of the mid-dorsolateral prefrontal cort ex in the monitoring of events in working memory. By contrast, a cortical b asal ganglia loop involving the mid-ventrolateral prefrontal cortex (area 4 7/12), caudate nucleus, and mediodorsal thalamus increased activity specifi cally during the reception of negative feedback, which signals the need for a mental shift to a new response set. The posterior prefrontal cortex resp onse was less specific; increases in activity occurred during both the rece ption of feedback and the response period, indicating a role in the associa tion of specific actions to stimuli. The putamen exhibited increased activi ty while matching after negative feedback but not while matching after posi tive feedback, implying greater involvement during novel than routine actio ns.