Abstract
Motor cortex stimulation (MCS) has been reported to control chronic deafferentation pain successfully. However, the detailed mechanisms of this action have not been made clear. To investigate the possible neural pathways involved in this effect, we measured pre- and post-MCS regional cerebral blood flow (rCBF) using positron emission tomography (PET).
Six patients with intractable pain in their left upper extremities were studied. All six were right handed and subdural electrodes were surgically placed over the right primary motor cortex. The rCBF was measured using PET with H215O during pre-MCS conditions of pain and post-MCS conditions of reduced pain. The PET images were analyzed with SPM99 statistical parametric mapping software. The rCBF during pain reduced conditions after MCS increased in left posterior thalamus, left posterior insula, right orbitofrontal cortex, and the left caudal anterior cingulated, when compared to that of the pre-MCS conditions of pain. This result suggests that MCS modulates both pain gait and emotion related pain.
