Cognitive stimulation with the Wisconsin Card Sorting Test: functional MR imaging at 1.5 T

To determine whether functional magnetic resonance (MR) imaging can demonstrate a specific pattern of cerebral activation during cognitive stimulation by using a high-level cognitive task such as the Wisconsin Card Sorting Test.

Thirty-one healthy volunteers underwent functional MR imaging with a 1.5-T MR imager with a standard head coil (100/50 [repetition time msec/echo time msec], 230-mm field of view, 40 degrees flip angle, 256 x 256 matrix). For stimulation, a personal computer version of the Wisconsin Card Sorting Test was used. Image analysis was done off-line, and cross-correlation coefficients between the stimulus function and the signal intensity response were calculated on a pixel-by-pixel basis and overlaid onto the corresponding anatomic MR image for each volunteer.

Stimulation resulted in strongly frontal activation, which included the mesial and the dorsolateral prefrontal cortexes, interconnected with Brodmann areas 44, 45, and 46. While activation was often bilateral, the largest area of activation was in the right hemisphere. Activation also was found in the basal ganglia and the mesial thalamic nuclei.

Functional MR imaging can demonstrate a specific pattern during activation with a cognitive task. Functional MR imaging has promise for more precise anatomic and functional imaging studies of brain interaction than have other imaging modalities.