"Our results suggest that meditation can produce experience-based structural alterations in the brain," says Sara Lazar, PhD, of the MGH Psychiatric Neuroimaging Research Program, the study's lead author. "We also found evidence that mediation may slow down the aging-related atrophy of certain areas of the brain."
Studies have shown that mediation can produce alterations in brain activity, and meditation practitioners have described changes in mental function that last long after actual meditation ceases, implying long-term effects. However, those studies usually examined Buddhist monks who practiced mediation as a central focus of their lives.
To investigate whether meditation as typically practiced in the U.S. could change the brain's structure, the current study enrolled 20 practitioners of Buddhist Insight meditation - which focuses on "mindfulness," a specific, nonjudgmental awareness of sensations, feelings and state of mind. They averaged nine years of mediation experience and practiced about six hours per week. For comparison, 15 people with no experience of meditation or yoga were enrolled as controls.
Using standard MRI to produce detailed images of the structure of participants' brains, the researchers found that regions involved in the mental activities that characterize Insight meditation were thicker in the meditators than in the controls, the first evidence that alterations in brain structure may be associated with meditation. They also found that, in an area associated with the integration of emotional and cognitive processes, differences in cortical thickness were more pronounced in older participants, suggesting that meditation could reduce the thinning of the cortex that typically occurs with aging.
"The area where we see these differences is involved in both the modulation of functions like heart rate and breathing and also the integration of emotion with thought and reward-based decision making - a central switchboard of the brain," says Lazar. An instructor in Psychology at Harvard Medical School, she also stresses that the results of such a small study need to be validated by larger, longer-term studies.
The study was supported by grants from the National Institutes of Health, the MIND Institute and the Centers for Disease Control and Prevention. Co-authors are Rachel Wasserman, Doug Greve, PhD, Michael Treadway, Brian Quinn, Scott Rauch, MD, and Bruce Fischl, PhD, of the MGH; Catherine Kerr, PhD, Harvard Medical School; Jeremy Gray, PhD, Yale University; Metta McGarvey, Harvard Graduate School of Education; Jeffery Dusek, PhD, and Herbert Benson, MD, Beth Israel Deaconess Medical Center and Mind/Body Medical Institute; and Christopher Moore, PhD, Massachusetts Institute of Technology and McGovern Institute for Brain Research.
Massachusetts General Hospital, established in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH conducts the largest hospital-based research program in the United States, with an annual research budget of nearly $500 million and major research centers in AIDS, cardiovascular research, cancer, cutaneous biology, medical imaging, neurodegenerative disorders, transplantation biology and photomedicine. In 1994, MGH and Brigham and Women's Hospital joined to form Partners HealthCare System, an integrated health care delivery system comprising the two academic medical centers, specialty and community hospitals, a network of physician groups, and nonacute and home health services.