Functional magnetic resonance imaging (FMRI) has detected changes
in regional cerebral blood flow and volume in response to motor
movements, visual stimuli, and auditory stimuli in each of their
respective primary cortices. This experiment was conducted to
determine whether signal changes in the somatosensory cortex secondary
to tactile stimulation could be demonstrated. The palm of the right
hand was periodically stimulated while the subject was undergoing
echo-planar imaging with a 1.5-T magnetic resonance scanner equipped
with local gradient and radio frequency coils. Sagittal and coronal
images of 10- to 15-mm slice thickness were selected to include the
postcentral gyrus and surrounding regions. Temporally correlated
signal changes of 1% to 5% occurred in the peri-rolandic region in
each of six subjects. The time course of signal changes was comparable
to that found in other primary sensory and motor cortices. The results
provide preliminary evidence of the sensitivity of FMRI to activation
of the somatosensory cortex with tactile stimulation and support FMRI
as a promising noninvasive technique for study of the functional
organization and integrity of the cerebrum.