Neural activities during Wisconsin Card Sorting Test - MEG observation

The present study recorded activities of magnetoencephalography (MEG) to th e presentation of cards, and to the presentation of feedback signals in 12 normal subjects while they performed the Wisconsin Card Sorting Test (WCST) , to observe temporal and spatial processing during the task, The MEG respo nses were compared between two different conditions in the presentation bot h of cards and of feedback signals: the cards proceeded by the first wrong [W1st(C)] and by the 4th correct feedback signals [C4th(C)]; and the feedba ck of the first wrong [W1st(FB)] and the 4th correct signals [C4th(FB)]. A multi-dipole model, brain electric source analysis (BESA), was used to expl ore the dipole sources responsible for the MEG activities, We found that ME G activity differences between the W1st(C) and the C4th(C) condition occurr ed in the period of 190-220 ms (M190 and M200), and 300-440 ms (M300 and M3 70) mainly at the supramarginal gyrus, the dorsolateral prefrontal, and the middle and inferior frontal gyrus. MEG differences between the W1st(FB) an d the C4th(FB) condition occurred 460-640 ms (M460) after the presentation of the feedback signals, with the activation of the dorsolateral prefrontal cortex and the middle frontal cortex. No significant location differences were found between the frontal responses (M370) of the W1st(C) and M460 of the W1st(FB). Our results proved that the WCST task activates a broad front al area and the parieto-frontal network across time streaming. Both shiftin g attention to the wrong feedback and enhanced visual working memory to the sorting shifting condition of the card presentation occur in the same area s at different time points, (C) 2001 Elsevier Science B.V. All rights reser ved.