Cerebral hemodynamics and processing speed during category learning.

The Wisconsin Card Sorting Test (WCST) is a commonly used paradigm of category learning with two alternating and distinct processes, maintaining set and set shifting that have been characterized by functional transcranial Doppler sonography (fTCD) of the basal cerebral arteries. Further, repeated WCST administrations resulted in improved speed of solution. This study addressed the question of whether optimised speed during maintaining set or set shifting is associated with changes of cerebral hemodynamics as measured by bilateral fTCD. During maintaining set, improved speed was associated with increased peak mean cerebral blood flow velocity (CBFV) of the anterior cerebral arteries. These results suggest a common functional substrate between optimised speed of solution and cerebral hemodynamics during maintaining set.