By Roni Caryn Rabin Published: May 2, 2011 The New York Times
Studies have found that meditation helps prevent the recurrence of depression, perhaps by producing changes in parts of the brain associated with learning and anxiety. A new study suggests that meditation may modulate brain waves called alpha rhythms, which help regulate the transmission of sensory input from the surrounding environment.
Harvard researchers randomly assigned 12 healthy adults to an eight-week course of training in meditation-based stress reduction or to a control group whose participants did not meditate.
At regular intervals, researchers used an imaging technique called magnetoencephalography to measure electrical currents in an area of the brain that processes signals from the left hand. During the tests, each participant was asked to direct his attention to his or her left hand or left foot.
After eight weeks, the brain scans showed that alpha rhythms changed more quickly and in a more pronounced way in participants who had been meditating.
“If you’re reading something in a noisy environment and you want to be in a bubble, you might use your alpha rhythms like a volume knob, to turn down the volume on neurons that represent sound from the outside world,” said Catherine E. Kerr, a neuroscientist at Harvard Medical School and a co-author of the report, published April 21 in the journal Brain Research Bulletin. “We all do this to some extent, but it turns out that meditators become much more skilled at it.”