The anatomy of the mesolimbic reward system: a link between personality and the placebo analgesic response.
The anticipation of clinical benefit, a crucial component of placebo analgesia, has been suggested to be a special case of reward anticipation. Since reward processing is closely linked to the ventral striatum and the neurotransmitter dopamine, we examined the relationships between brain gray matter, placebo analgesic response, and personality traits associated with dopaminergic neurotransmission. We report that dopamine-related traits predict a substantial portion of the pain relief an individual gains from a sham treatment. Voxel-based morphometry of magnetic resonance images shows that the magnitude of placebo analgesia is related to gray matter density (GMD) in several brain regions, including the ventral striatum, insula, and prefrontal cortex. Similarly, GMD in ventral striatum and prefrontal cortex is related to dopamine-related personality traits. Our findings highlight the relationship between placebo and reward and potentially offer ways of identifying subjects who are likely to show large placebo analgesic responses.
Alan Edwards Centre for Research on Pain, Faculty of Dentistry, McGill University, Montreal, Quebec, Canada H3A2B2. petra.schweinhardt@mcgill.ca
Petra
P
Schweinhardt
David A
DA
Seminowicz
Erik
E
Jaeger
Gary H
GH
Duncan
M Catherine
MC
Bushnell
D000287:Administration, Topical; D000293:Adolescent; D000328:Adult; D000700:Analgesics / Q000008:administration & dosage*; D018592:Cross-Over Studies; D006801:Humans; D008032:Limbic System / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008636:Mesencephalon / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology; D010147:Pain Measurement / Q000187:drug effects / Q000379:methods / Q000523:psychology; D010551:Personality / Q000187:drug effects / Q000502:physiology*; D015990:Placebo Effect; D012201:Reward; D055815:Young Adult
D000700:Analgesics