Studies have shown that ­meditating regularly can help relieve chronic pain, but the neural mechanisms ­underlying the relief were unclear. Now, ­researchers from MIT, Harvard, and Massachusetts General ­Hospital have found a possible explanation.

In a recent study published in the journal Brain Research Bulletin, the researchers found that people trained to meditate over an eight-week period were better able to control a specific type of brain waves, called alpha rhythms.

“These activity patterns are thought to minimize distractions, to diminish the likelihood stimuli will grab your attention,” says Christopher Moore, PhD ‘98, an investigator at the ­McGovern Institute for Brain Research at MIT and senior author of the paper. “Our data indicate that meditation ­training makes you better at focusing, in part by allowing you to better regulate how things that arise will impact you.”

Several different types of brain waves help regulate the flow of information between brain cells. Alpha waves, the focus of this study, flow through cells in the brain’s cortex, where sensory information is processed. The alpha waves help suppress irrelevant or distracting sensory information.

A 1966 study showed that a group of Buddhist monks who meditated regularly had elevated alpha rhythms across their brains. In the new study, the researchers followed 12 subjects who had never meditated before and looked at the waves’ role in a specific part of the brain—cells of the sensory cortex that process tactile information from the hands and feet. Half the participants were told not to meditate, while the other half were trained in a technique called mindfulness-based stress reduction. The first two weeks of training were devoted to learning to pay close attention to body sensations.

After eight weeks, the subjects who had been trained in meditation showed larger changes in the size (amplitude) of their alpha waves when asked to pay attention to a certain body part—for example, the left foot. In addition, these changes in wave size occurred more rapidly in the meditators.

Subjects in this study did not suffer from chronic pain, but the findings suggest that in pain sufferers who meditate, the beneficial effects may come from an ability to essentially turn down the volume on pain signals. “They learn to be aware of where their attention is focused and not get stuck on the painful area,” says ­Catherine Kerr, an instructor at Harvard Medical School and a lead author of the paper.

The subjects trained in meditation also reported that they felt less stress than the nonmeditators. The researchers are considering follow-up studies in patients who suffer from chronic pain as well as in cancer patients, who have also been shown to benefit from meditation.