Why can mental distraction dull physical pain?

THAT'S THE WHY:HAVE YOU ever noticed that taking your mind off a pain can sometimes help to cope with it? Why could a mental distraction help lessen the physical sensation? Research in Germany suggests that distraction can inhibit the response to incoming pain signals as the central nervous system starts to process them. The study asked 20 healthy, male volunteers to concentrate on hard or easy mental tasks, and at the same time heat was applied to their arms to cause pain.

Pain ratings tended to be lower for people when faced with the harder problem than if they were cruising through a less distracting mental task. Images of their spinal cords backed this up: functional MRI scans showed reduced activity there during the harder task.

“The results demonstrate that this phenomenon is not just a psychological phenomenon, but an active neuronal mechanism reducing the amount of pain signals ascending from the spinal cord to higher-order brain regions,” said researcher Christian Sprenger of the University Medical Center Hamburg-Eppendorf in a release.

To get an idea of why this might be happening, the researchers gave some participants – again all male – a drug that blocks the body’s own naturally occurring opioid pain- relieving chemicals, or else a placebo. Taking the opioid-blocking drug seemed to reduce the pain-relieving effects of distraction. That suggests the body’s own opioids play a role in distraction’s pain-dulling effects.

“Our results show that the reduced pain experience during mental distraction is related to a spinal process and involves opioid neurotransmission,” write the authors in Current Biology.