The health benefits of meditation—lowering blood pressure, improving immune function, decreasing stress—are well recognized, but can meditative practice actually change the brain? Growing evidence from neuroscience suggests that it can, providing increasing support for the idea that meditation alters both the function and structure of the brain.
“Science is beginning to take this seriously,” said Richard Davidson, a neuroscientist at the University of Wisconsin, Madison, who has been at the forefront of research on the brain effects of meditation. Although he cautioned that the results so far are very preliminary and should not be oversold, he is encouraged by the overwhelmingly positive response from neuroscientists to the idea of applying rigorous scientific methods to the study of meditation.
At Harvard Medical School, Sara Lazar took magnetic resonance imaging (MRI) scans of 20 subjects who were students of “insight meditation,” which focuses on breath awareness and bodily sensations, and compared them with brain scans from 15 people with no meditation or yoga experience. Her team found that specific cortical regions of the brain were significantly thicker in people who meditated than in those who did not.
The differences were particularly evident in the insula, a brain region Lazar said acts as a “control switchboard,” integrating thoughts and emotions with basic physiological functions such as heart rate, and in the prefrontal cortex, which is associated with working memory, decision-making, and cognitive-emotional interactions.
Cortical thickening was correlated with experience: the longer a subject had been practicing meditation, the thicker the cortex was. Differences in the prefrontal cortex, an area that typically gets thinner as we age, were most pronounced in older subjects, leading Lazar to conjecture that meditation may circumvent this age-related effect. The study scanned subjects only once, but Lazar is in the process of following up with additional scans that will track brain changes at various times following the start of meditation practice.
Meanwhile, the latest research from Davidson’s group suggests that long-term meditation practice leads to higher levels of specific brain waves, called “gamma-band rhythms,” that are associated with higher mental activities such as attention, learning, and conscious perception. His team compared nine people who had practiced more than 10,000 hours of Buddhist meditation, which focuses on generating kindness and compassion toward all beings, to people of the same ages who had no meditation experience. Gamma waves increased sharply among the long-term meditators during their practice, and remained higher after meditation.
“This suggests that long-term meditation practice changes the baseline state of the brain,” Davidson said.
Fluctuations in the brain wave pat-terns of meditators also correlated moment-by-moment to the “intensity of clarity” that the practitioners reported during meditation, suggesting a direct effect on attentional processes. These data are consistent with other emerging evidence suggesting that meditation increases attention skills and the capacity to control and stabilize mental processes.