Brain Knows Imagined Pain

Brain Knows What's Real, What's Not

From the WebMD Archives

Feb. 1, 2005 -- Both real and imagined pain will register very similarly in the brain, new research shows. Yet the brain accurately translates which experience is real and which isn't.

Recent studies have shown that pain-related areas of the brain can be activated without any injury -- only through verbal cues that create "psychological" or imaginary pain, writes researcher Tuukka T. Raij, MD, with the brain research unit at the Helsinki University of Technology in Finland.

But how does the brain perceive imaginary pain, compared with real pain? Raij's report answering that question appears in the January early online edition of Proceedings of the National Academy of Science.

Raij's study involved 14 people, all of whom were tested to ensure they were "suggestion prone" --hypnotizable. Each allowed researchers to induce pain, either through laser pulses to the skin, or hypnotic suggestion. Each "pain procedure" took place while the volunteer was inside a functional MRI machine. The fMRI allowed researchers to track the brain's pain circuitry during each type of test. After the test, volunteers were asked to rate the pain.

The test showed that the brain responded similarly to both types of pain.

The pain centers of the brain were activated in response to both the laser -- which created a burning and aching pain -- and to the post-hypnotic suggestion that they were experiencing pain.

However, during the laser tests, the brain's pain circuitry was more strongly activated. Also, all 14 volunteers estimated the reality of pain to be higher during the laser test, compared with the hypnosis test, reports Raij.

The study supports the view that the brain can separate real from imagined pain -- however similar they may seem.

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SOURCES: Raij, Tuukka T. Proceedings of the National Academy of Sciences, January 2005. News release, PNAS.
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