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NEUROPSYCHOLOGY: Hold'em, Fold'em
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Gilbert J. Chin

One of the most widely used tests of deficits in prefrontal cortex (PFC)
function (as might occur in patients with brain damage) is the Wisconsin
Card Sorting Task (WCST). Test cards must be matched to one of a set of
reference cards on the basis of common color, number of items, or the shape
of the item represented on the card. Changing the classification criterion
tests for two components of executive function: shifting to a new set of
rules and monitoring recent events that are held in working memory.

Monchi et al. have used event-related functional brain imaging to obtain
supporting evidence for the existence of coincident activity in areas
within the PFC and the basal ganglia, as would be expected if circuits
connecting these areas subserved the executive function. They observed that
midventrolateral PFC (Brodmann area 47/12) and the caudate were both active
after negative feedback had been given, meaning that a rule change had
occurred and thus that set-shifting was required. The middorsolateral PFC
(area 9/46) was active after both negative and positive feedback,
suggesting that this area was involved in monitoring performance and
accessing working memory. The putamen, another part of the basal ganglia,
was active during the match made after negative feedback, consistent with a
role in executing a novel action. -- GJC

J. Neurosci. 21, 7733 (2001).