Chronic Pain Due to Mixed Up Brain

Chronic pain could be a malfunction of the brain's body map, new research suggests. Training the brain to disassociate pain from these areas could be a promising approach for treating phantom limb pain and other pain syndromes.

Often painful stimuli triggered by a broken bone or other trauma cause the brain to rewire and, as a result, the damage signal is never switched off after the initial body trauma is resolved. The result: Chronic pain. So if the brain is capable of changing to cause persistent pain, can it be changed back to normal to alleviate pain?

"We're learning that chronic pain is associated with disruption of brain maps of the body and of the space around the body," study researcher G. Lorimer Moseley, of the University of South Australia said in a statement. "When the brain determines the location of a sensory event, it integrates the location of the event in the body with a map of space. Disruption of these processes might be contributing to the problem."

The research was presented today, May 18, at the American Pain Society's Annual Scientific Meeting in Hawaii.

Researchers have known for some time that the brain stores maps of the body that are integrated with neurological systems that survey, regulate, and protect the integrity of the body physically and psychologically.

These cortical maps govern movement, sensation and perception, and there is growing evidence showing that disruptions of brain maps occur in people with chronic pain, like phantom limb pain.

It is possible for the body to be unharmed but the brain will respond by causing pain because it misinterpreted a benign stimulus as an attack. "We want to gradually train the brain to stop trying to protect body tissue that doesn't need protecting."

The researchers are studying now how the changes in the brain and mind can be normalized with treatment. Moseley said the brain can "rewire" itself, a process called neuroplasticity.

"The brain is the focal point of the pain experience, but the plasticity phenomena can be harnessed to help alleviate pain," Moseley said.

He further stated that disrupted cortical body maps may contribute to the development or maintenance of chronic pain and, therefore, could be viable targets for treatment.

One treatment approach involves targeting motor systems through a process Moseley calls "graded motor imagery." It relies on using visual images to help the brain change its perceptions of the body after prolonged pain stimuli.

"For someone with phantom limb pain, the brain's body map still includes the severed arm or leg, and without any real stimuli from the region, it continues to produce pain," Moseley said. "Our work shows that the complex neural connections in the brain not only are associated with chronic pain, they can be reconnected or manipulated through therapy that alters brain perceptions and produce pain relief."