Listening to verbal suggestions of increased or decreased pain, after a hypnosis induction, produces brain activity changes that predict how the brain later responds to painful stimuli. Suggestions of hyperalgesia and hypoalgesia, compared to control suggestions, decreased brain activity in the parietal operculum and anterior midcingulate cortex, and increased activity in the left parahippocampal gyrus. These activity changes predicted larger pain-evoked brain responses after hyperalgesia suggestions and smaller pain-evoked responses after hypoalgesia suggestions, consistent with participants' reported pain perception. The findings suggest that verbal suggestions transform into predictive signals that modulate pain processing, supporting a predictive coding framework.
Focused hypnotic analgesia (FHA) can selectively reduce pain in a targeted body part without affecting other areas. In 40 healthy participants, brief heat stimuli were applied to both arms before, during, and after a hypnotic suggestion targeting one arm. During FHA, pain intensity and unpleasantness decreased significantly for the protected arm compared to before and after, while the unprotected arm showed no change. Ratings differed between arms only during the suggestion. These effects occurred regardless of participants' hypnotizability. The findings indicate FHA modulates both sensory and emotional pain components and can spatially restrict its analgesic effects.