EFFECTS OF HYPNOSIS ON REGIONAL CEREBRAL BLOOD-FLOW DURING ISCHEMIC PAIN WITH AND WITHOUT SUGGESTED HYPNOTIC ANALGESIA

Using Xe-133 regional cerebral blood flow (CBF) imaging, two male grou ps having high and low hypnotic susceptibility were compared in waking and after hypnotic induction, while at rest and while experiencing is chemic pain to both arms under two conditions: attend to pain and sugg ested analgesia. Differences between low and. highly-hypnotizable pers ons were observed during air hypnosis conditions: only highly-hypnotiz able persons showed a significant increase in overall CBF, suggesting that hypnosis requires cognitive effort. As anticipated, ischemic pain produced CBF increases in the somatosensory region. Of major theoreti cal interest is a highly-significant bilateral CBF activation of the o rbito-frontal cortex in the highly-hypnotizable group only during hypn otic analgesia. During hypnotic analgesia, highly-hypnotizable persons showed CBF increase over the somatosensory cortex, while law-hypnotiz able persons showed decreases. Research is supportive of a neuropsycho physiological model of hypnosis (Crawford, 1991; Crawford and Gruzelie r, 1992) and suggests that hypnotic analgesia involves the supervisory , attentional control system of the far-frontal cortex in a topographi cally specific inhibitory feedback circuit that cooperates in the regu lation of thalamocortical activities.