TAKE A DEEP BREATH; MEDITATION MAY BOOST BRAIN SIZE AND INCREASE MENTAL PERFORMANCE, ACCORDING TO NEW RESEARCH
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TAKE A DEEP BREATH; MEDITATION MAY BOOST BRAIN SIZE AND INCREASE MENTAL PERFORMANCE, ACCORDING TO NEW RESEARCH
WASHINGTON, DC, November 13, 2005 — The ohms and ahs of meditation do more than provide feelings of serenity and peace; they also transform the structure and function of the brain, according to a series of new studies.
Although Buddhist monks and many westerners have been meditating for years, only recently have scientists begun to study how the practice affects the brain. Now new research presented at this meeting provides evidence that meditation may be able to create important brain changes, perhaps including an actual boost in brain size as well as alterations in brain activity that aid mental performance and increase attention.
In one of the studies, researchers used the imaging technique, MRI, to examine the physical structure of the brains of meditation practitioners in the U.S. “Our findings provide the first evidence that alterations in brain structure are associated with western-style meditation practice, possibly reflecting increased use of specific brain regions,” says Sara Lazar, PhD, of Harvard Medical School.
Unlike Tibetan Buddhist monks, who have devoted their lives to the practice of meditation and their religion, meditation practitioners in the U.S. usually meditate just 20 to 60 minutes per day and incorporate their practice into a daily routine involving career, family, friends, and other outside interests, according to Lazar. Additionally, many American meditation students view meditation as a source of stress-reduction, mental exercise or personal growth, and do not necessarily incorporate traditional eastern religious elements into their practice.
Lazar and her colleagues compared the brains of 20 western-style meditators with 15 people who had no meditation or yoga experience. The meditators were students of Buddhist “Insight” meditation, which focuses on the cultivation of a trait called mindfulness, a specific, non-judgmental awareness of present-moment sensory stimuli. All study participants laid quietly in the MRI scanner while detailed images were taken of the structure of their brains.
“We found that brain regions associated with attention and sensory processing were thicker in meditators than in the non-meditators,” says Lazar. “Also, in one of the regions, the differences in thickness were most pronounced in older subjects, suggesting that regular practice of meditation might reduce normal age-related thinning of the brain.” This region is an area of the brain’s outer layer or cortex, which is thought to be involved in integrating emotional and cognitive processes.
“Although numerous studies examining cortical thickness have pointed to aging and pathology as sources of cortical thinning, there has been limited work indicating mechanisms promoting cortical thickening,” says Lazar. “Our findings suggest that meditation practice can promote cortical changes in adults in areas important for cognitive and emotional processing and well-being.”
It is possible that people who naturally have a thicker cortex in areas associated with awareness and sensory processing are more likely to practice meditation. However, the pattern of cortical thickening corresponds well to the specific activities that practitioners of Insight meditation repeatedly engage in over time: paying attention to breathing sensation and sensory stimuli, according to Lazar. Additionally, the observed increases in cortical thickness were proportional to the amount of time the participant had spent meditating over their lifetime.
“While additional research needs to be done, our results do suggest that the observed differences are acquired through extensive practice of meditation and are not simply due to incidental between-group differences,” says Lazar. “We also believe that other forms of yoga and meditation would have a similar impact on brain structure.”
Other researchers from the University of Kentucky examined whether meditation might involve brain functions similar to sleep. Although meditation is a form of wakefulness, meditation, like sleep, is also reported to be relaxing and restorative.
“We used a well-validated test to examine whether meditation might be restorative in similar or different ways than sleep,” says Bruce F. O’Hara, PhD. “Our research suggests that meditation serves a performance-enhancing and perhaps restorative role even in novice meditators.”
In the first part of the study, O’Hara, graduate student Prashant Kaul, and undergraduate student Jason Passafiume measured study participants’ performance on a test referred to as the Psychomotor Vigilance Task in the mid-afternoon, when people tend to be sleepier and vigilance typically wanes. This test measures subjects’ sleepiness, with performance on the test getting progressively worse with increasing sleep debt. During the study, participants were tested before and after 40 minute periods of meditation, sleep, or a control activity. All ten subjects underwent multiple sessions of each activity, and showed a significant improvement in performance five minutes following meditation and a significant decline in performance following a nap.
Previous studies have shown that naps tend to improve performance several hours later, but often cause worse performance immediately following a nap (unless the nap is very short). “The improved performance following meditation was remarkably consistent with all ten subjects showing at least some improvement,” says O’Hara.
Seven of the ten subjects were also tested following a full night of sleep deprivation, which is known to decrease performance on the Psychomotor Vigilance task. “The participant’s improvement was even greater following meditation in this sleep deprived state in six out of the seven subjects, and all seven had decreased lapses,” says O’Hara.
The subjects in this study had either no prior meditation experience, or moderate prior experience, and there was no obvious difference related to prior mediation experience. “This suggests that meditation can benefit even novice meditators,” says O’Hara. “In addition, the short term boost in performance might be especially helpful for many people with excessive day-time sleepiness, and might even be an alternative for the 80 percent of adults who use caffeine for a daytime performance boost.”
As a next step, the researchers are comparing the performance effects of caffeine versus meditation. In addition, they have begun studies in India (where Kaul was a medical doctor) with accomplished Yogis who are able to regularly spend several hours a day in meditation, but have also agreed to forego meditation on designated days. By comparing sleep time, meditation time, and various performance measures, they believe they can address whether meditation may be able to partially replace sleep. “If so, this would be the first waking activity known that can, at least in part, replace the mysterious but critical functions of sleep,” says O’Hara.
In other work, Richard J. Davidson, PhD, and his colleagues at the University of Wisconsin discovered that long-term meditation practices create brain activity alterations that are thought to aid complex mental processes, such as attention.
The study compared the brain activity of long-term Buddhist meditation practitioners that had over 10,000 hours of meditation experience with the brain activity of a group of healthy age-matched volunteers who had no experience in meditation but who were all taught meditation prior to the experiment. Participants were asked to generate a standard meditation state several times, alternating with a resting state. The type of meditation each group pursued involved the voluntary generation of compassion and loving kindness. It did not involve concentration on particular objects, memories or images, but instead encouraged the practitioner to generate loving kindness and compassion toward all feeling beings without thinking about anyone in particular.
Before, during, and after the meditation practice, researchers recorded “gamma band rhythms,” brain impulses that are associated with higher mental activity such as attention, learning, and conscious perception. “We confirmed that the Buddhist monks had a higher level of gamma band rhythms than nonmeditators,” says Davidson. “This suggests that long-term meditation practice changes the baseline state of the brain.”
The researchers also found that the difference between the two groups increased sharply during meditation and remained higher than the baseline after meditation. And, following each period of meditation in the post-meditation baseline state, the long-term practitioners continued to display a high level of gamma band rhythms compared with the controls.
Researchers also asked six long-term practitioners to rate the ongoing intensity of their meditation using a scaling arrow on a computer screen while they examined their brain activity. “We found that changes in brain activity correlated to moment-to-moment changes in experience during the meditation session,” says Davidson. “Further studies are needed to assess the behavioral consequences of all these changes as well as the short and long-term impact on the brain of these brain activity patterns.”
Other researchers found evidence that meditation can increase attention skills and the ability to stabilize the mind. “Our results support the claim that training in meditation can have a real and measurable effect on an individual’s conscious state,” says Olivia Carter, PhD, of Harvard University. “Although the current study provides no direct evidence that meditation will help alleviate the symptoms of depression or stress, the findings are consistent with reports that experienced meditators are able to control and direct the focus of their attention towards a positive and calm state, in a manner that may help reduce symptoms of stress and depression.”
In the study, Carter and her colleagues examined 76 Tibetan Buddhist monks who had attained meditative training ranging from 5 to 54 years. She examined the ability of meditation to alter their conscious perception using a measure called perceptual rivalry—a visual illusion that is one of the most commonly used tools in scientific studies of consciousness. Perceptual rivalry refers to oscillations in visual perception that can occur during sustained viewing of ambiguous visual stimuli. One famous example involves an image that can be perceived as either two faces or a vase. When this image is viewed the observer’s conscious experience will generally switch between the two “competing” interpretations of the image. Only one of the two images will be consciously perceived at any given moment, while the non-dominant image will be totally suppressed from consciousness. After a few seconds, the relative dominance of the two images will then switch. The neural events underlying perceptual rivalry are not well understood, but are thought to involve mechanisms within the brain that regulate attention and conscious awareness.
The monks perceptual experience of visual rivalry was tested during two types of meditation: a “compassion”-oriented meditation, described as a contemplation of suffering within the world combined with an emanation of loving kindness, and “one-point” meditation, described as the maintained focus of attention on a single object or thought that leads to a stability and clarity of mind. “We found that increases in the durations of perceptual dominance were experienced by monks practicing one-point meditation, but not compassion meditation,” says Carter.
In a different test of perceptual rivalry called motion induced blindness, in this case prior to any meditation, the duration of stable perception experienced by monks averaged 4.1 seconds, compared to 2.6 seconds for meditation-naïve control participants. “Remarkably, when instructed to actively maintain the duration of perceptual stability, one of the monks who studied mediation for many years could maintain a constant visual perception during this test for 723 seconds,” says Carter. “The findings suggest that processes particularly associated with one-point meditation, perhaps involving intense attentional focus and the ability to stabilize the mind, contribute to the prolonged rivalry dominance experienced by the monks.”
