Biomedicine

Mind-Control Over Pain

A new brain imaging technique teaches patients to control their brain activity, bringing relief from chronic pain.

Most people pop a pill when they’ve got a headache. But what if you could think that pain away? Researchers at Stanford University have developed a brain imaging technique that allows patients to take charge of their pain. The technology isn’t yet ready for the clinic, but researchers say it could one day be applicable to many brain disorders, such as depression, anxiety, and dyslexia.

“This is the first study to show that patients can learn to take control of a specific region of their brain and better control their pain,” says Sean Mackey, associate director of the Pain Management Division at Stanford University in Stanford, CA, and head scientist on the project research.

Mackey and collaborators used a technique called real-time functional magnetic resonance imaging (rtfMRI) where both subjects and researchers can look at the brain’s activity as the person thinks. In this case, researchers broadcast the activity from a part of the brain involved in pain processing – the anterior cingulated cortex – into the scanner. Patients watched the activity and tried to decrease it by doing mental exercises, such as focusing on a part of the body where they did not have pain. The process is similar to biofeedback, where people learn to control blood pressure or heart rate by getting constant feedback on their vital signs.

Eight patients with chronic pain that wasn’t adequately controlled by more conventional means reported a 44 percent to 64 percent decrease in pain after the training, a benefit that was three times larger than the pain reduction reported by a control group. Those who exercised the greatest control over their brain activity showed the greatest benefit in pain reduction. The results were published last week in the Proceedings of the National Academy of Sciences.

“I look forward to seeing if this result could be replicated in larger numbers of patients,” says Richard Gracely, a neurologist who specializes in pain research at the University of Michigan Medical School in Ann Arbor, MI. “It could be very promising for providing another method for control over pain in clinical conditions, especially where there are no other effective means in reducing pain.”

Mackey and his collaborator, Christopher deCharms, of Omneuron in Menlo Park, CA, are running a long-term clinical trial with chronic pain patients to determine if imaging therapy could really be a useful alternative to drugs or surgery. But they caution that the technology is not ready for clinical use – they don’t know how long the effect lasts and say some people learn the technique easier than others.

“It’s not an approach that’s suitable for everyone. Patients have to be motivated, which not all pain patients are,” deCharms says. “But if you could sustain a 50 percent decrease in pain, it could change the life of a person with debilitating pain.”

Mackey and deCharms will also determine if the therapy could be used for other disorders, such as depression, by teaching patients to control parts of their brains that have been implicated in those disorders. “Many diseases are localized to particular brain regions. Depression is localized to the serotonin system, Parkinson’s to the dopamine area,” says deCharms. “Maybe this technology could be used to control brain processes, rather than using a drug.”

Other fMRI experts say it’s too soon to say how widely applicable the imaging therapy could be. According to James Brewer, a neurologist at the University of California, San Diego, some parts of the brain may be more amenable to conscious control than others. The current experiment targeted the anterior cingulate cortex, a brain area that has been implicated in attention. It may be easier to voluntarily control a brain area involved in attention, which humans consciously control as they shift between activities like conversing or watching TV, than areas involved in other functions.

While the field is still in its infancy, several scientists are excited about exploring its possibilities. “The field of neurofeedback is wide open, it’s something that makes a lot of sense to investigate,” says Tor Wager, a psychologist at Columbia University in New York. “We need more research that explores what people can do themselves.”

John Gabrieli, a neuroscientist at MIT who collaborated on the current paper, says he wants to assess if a similar technique can be used to help children with learning disorders. For example, kids with dyslexia have a deficit in a particular brain circuit involved in language. Remedial reading programs can activate this brain area. Gabrieli plans to determine if activating this region with fMRI feedback could enhance the effectiveness of traditional reading programs.

The technique could also be promising in cases of stroke. “When a person has a stroke in [one part of the brain], activity in another part of brain sometimes compensates,” says Brewer. If researchers could figure out where and why that happens, exercising that part of the brain through focused attention may enhance recovery, he says.

Such applications are still down the road, but the current findings are giving hope that the approach can in fact ease pain. “All people have built into their brain a powerful physiological system to control pain,” says deCharms. “We’re training people to gain control over this system themselves.”

This is the first part in an occasional series that explores how new approaches to brain imaging could improve treatment of neurological and psychiatric disorders. A second installment, running on Thursday, December 22, will examine how understanding the neurobiology of the human subconscious could modernize psychoanalysis.

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