Somatosensory event-related potential changes to painful stimuli during hypnotic analgesia: anterior cingulate cortex and anterior temporal cortex intracranial recordings.

The present study examined neurophysiological correlates of pain and pain control by recording intracranial somatosensory event-related potentials (SERPs) to painful cutaneous stimuli in two female patients with obsessive-compulsive disorder bearing multiple intracranial electrodes during conditions of (a) attention and (b) hypnotically suggested analgesia. Intracranial electrodes were located in the anterior cingulate cortex, amygdala, temporal cortex, and parietal cortex. No changes were observed in the SERPs of the hypnotically unresponsive patient. In the hypnotically responsive patient, reduced pain perception during suggested hypnotic analgesia was accompanied by (a) a significant reduction of the positive SERP component within the range of 140-160 ms post-stimulus in the left anterior cingulate cortex (Shaltenbrandt atlas: 29.12/ -7.42/32.41), and (b) a significant enhancement of the negative SERP component within the range of 200-260 ms in the left anterior temporal cortex (Brodmann area 21). No significant changes were observed in the amygdala or the scalp-recorded Fz. The present study is the first to demonstrate the involvement of the anterior cingulate cortex and the anterior temporal cortex in the control of pain with hypnotically suggested analgesia.