Preliminary evidence indicates that people can quell either temporary or chronic physical pain by learning to use their minds to reduce activity in a key brain area.
Brain-imaging technology now enables individuals to use mental exercises to control a neural region that contributes to pain perception, say neuroscientist Sean C. Mackey of Stanford University and his colleagues.
Both healthy volunteers and chronic-pain patients "learned to control their brains and, through that, their pain," Mackey holds. "However, significantly more testing must be done before this can be considered a treatment for chronic pain."
The new findings appear in the Dec. 20 Proceedings of the National Academy of Sciences.
Mackey's team studied 32 healthy volunteers, ages 18 to 37. First, each volunteer reported when an adjustable heat pulse applied to a leg produced pain that he or she rated as 7 out of 10, with 10 being equivalent to "the worst pain imaginable." Brain imaging of participants, using a functional magnetic resonance imaging (fMRI) scanner, showed that this level of pain was accompanied by pronounced blood flow—a sign of intense neural activity—in an area called the rostral anterior cingulate cortex.
Eight of the volunteers then underwent brain training. Each reclined in an fMRI machine that visually displayed activity changes in the person's rostral anterior cingulate cortex. A virtual flame dimmed as activity fell and brightened as activity surged.
While watching this display for 39 minutes, participants tried various mental strategies both to increase and to decrease their brain activity during brief periods of heat-pulse application. The experimenters suggested tactics such as focusing attention away from the pain.
By the end of the training session, the volunteers had learned to raise or lower activity in the critical brain area, the researchers say. The eight volunteers rated pain much higher during robust anterior cingulate cortex activation than during periods of lesser activity in that region.
No such brain-related pain effects occurred for the remaining 24 participants, who were instructed to change their brain activity when they were outside the fMRI machine or in the machine but receiving no feedback, when they received feedback from brain areas unrelated to pain, or when they viewed someone else's pain-related brain activity.
Next, eight chronic-pain patients completed anterior-cingulate-cortex training. Afterward, each reported much less pain—often less than half as much as usual—while he or she mentally quelled the region's activity.
Another four chronic-pain patients used physiological feedback—so-called biofeedback—to learn to control their heart rate, skin conductance, and breathing. None succeeded in lessening pain.
Neuroscientist Gary H. Duncan of the University of Montreal calls the new study "a landmark contribution of brain imaging to pain research." It demonstrates that self-control over activity in a specific brain region is possible, paving the way for explorations of neural function far beyond the treatment of chronic pain, he says.
Gary H. Duncan
Départment de stomatologie
Centre de recherche en sciences neurologies
Univerisité de Montréal
C.P. 6128, Succ. A
Montréal, QC H3C 3J7
Sean C. Mackey
Department of Anesthesia
Division of Pain Management
Stanford, CA 94305
A version of this article written for younger readers is available at Science News for Kids.