Previous neuroimaging studies of the Stroop task have postulated
that the anterior cingulate cortex (ACC) plays a critical role
in resolution of the Stroop interference condition. However,
activation of the ACC is not invariably seen and appears to
depend on a variety of methodological factors, including the
degree of response conflict and response expectancies. The present
functional MRI study was designed to identify those brain areas
critically involved in the interference condition. Healthy subjects
underwent a blocked-trial design fMRI experiment while responding
to 1 of 3 stimulus conditions: (1) incongruent color words,
(2) congruent color words, and (3) color-neutral words. Subjects
responded to the printed color of the word via a manual
response. Compared to the congruent and neutral conditions,
the incongruent condition produced significant activation within
the left inferior precentral sulcus (IpreCS) located on the
border between the inferior frontal gyrus, pars opercularis
(BA 44) and the ventral premotor region (BA 6). Significant
deactivations in the rostral component of the ACC and the posterior
cingulate gyrus were also observed. Selective activation of
the left IpreCS is compatible with findings from previous
neuroimaging, lesion, electrophysiological, and behavioral studies
and is presumably related to the mediation of competing
articulatory demands during the interference condition.
(JINS, 2002, 8, 735–742.)