FMRI OF HUMAN SOMATOSENSORY AND CINGULATE CORTEX DURING PAINFUL ELECTRICAL NERVE-STIMULATION

FUNCTIONAL MRI (fMRI) can detect changes from resting levels of blood flow and oxygenation during task performance (i.e. activation). We use d a simple electrical nerve stimulation technique together with fMRI t o study pain processes in the human cortex. Images of the primary soma tosensory (SI) and cingulate cortex (Cg) were obtained from subjects d uring stimulation at painful and non-painful intensities. Stimuli that evoked non-painful tingling sensations activated the contralateral SI but not Cg. Stimuli that evoked painful sensations activated both the contralateral SI and Cg. These data indicate that fMRI can detect pai n-related changes in SI and Cg evoked by electrical stimulation of per ipheral nerves. These findings add to the evidence for a role of SI an d Cg in human pain processes and provide a simple method of stimulus d elivery for its study.