| |
Abstract:
We investigated the functional neuroanatomy of the Stroop
task using fMRI in young and older adults. The Stroop effect is
common in all adults but it is exaggerated in older adults,
purportedly because younger adults are better able to inhibit the
overlearned word reading response. Young and older adults (13 each)
completed a counterbalanced design of the Stroop with six runs of
four 12-word blocks of congruent, neutral, and incongruent
conditions, whereby response to one of four colors required
pressing a corresponding button. Contiguous 7 mm sagittal
echo-planar slices were collected (TR = 4000 msec) at 1.5T with
anatomic co-localization. Images were averaged for each condition
and the mean differences were compared voxel-by-voxel between
activation conditions using t-tests. A combined cluster map was
created and average cluster values were extracted for each
participant and used to compute a between-groups t-test. Young
adults were more accurate across conditions, though response speed
was comparable between groups. Older adults exhibited greater
activation than the young in the left inferior, middle, and medial
frontal gyri and left cingulate in the I-C comparison. The results
are consistent with our studies of motoric inhibition in older
adults, showing that older adults have impaired IC and they appear
to recruit additional prefrontal regions to complete the
task.
|
