Research News

What does pain look like?

BMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f2386 (Published 17 April 2013) Cite this as: BMJ 2013;346:f2386

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Researchers from the US have identified a potential cerebral signature for physical pain—a pattern of brain activity that seems to discriminate reliably between physical pain and other experiences such as warmth, the anticipation of pain, remembering pain, or even the emotional pain triggered by a photograph of an ex-lover.

The researchers used functional brain imaging to map the cerebral responses of 114 volunteers to increasing thermal stimuli applied to the forearm. A pattern emerged in response to acute thermal pain that was more than 90% sensitive and more than 90% specific. It was bilateral and included multiple cerebral regions including the thalamus, insulae, secondary somatosensory cortex, anterior cingulate cortex, and periaqueductal grey matter. Cerebral responses diminished substantially in response to infusions of a powerful opioid analgesic.

Can we use this signature to confirm self reported pain or to identify pain in people who can’t communicate? Not yet, says a linked editorial (p 1447). This preliminary work paves the way for future research on the cerebral responses to clinical pain or chronic pain, which may be different. We may eventually need a whole suite of signature patterns for different types of pain, caused by different diseases, in different parts of the body, say the authors. All will need testing in bigger, more diverse populations.

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Cite this as: BMJ 2013;346:f2386