Thursday, 24 November 2005

How meditation alters the brain

New evidence suggests meditating can make parts of the cerebral cortex thicker and protect other parts from age-related thinning.

Sara Lazar and colleagues at Massachusetts General Hospital scanned the brains of 20 people who meditated for an average of 40 minutes per day and 15 controls with no meditation experience. The meditating participants were practitioners of Buddhist Insight meditation, which involves concentrating on stimuli ‘in the moment’, in a non-judgmental way and without cognitive elaboration – a process known as ‘mindfulness’.

Controlling for age and education, the researchers found that specific areas of the cortex were thicker in the participants who meditated compared with controls. These areas included the right anterior insula, known to be involved in monitoring bodily functions, and parts of the prefrontal cortex involved in attention and sensory processing. The observed differences in the insula are consistent with the fact Insight meditation involves concentrating on bodily sensations, including breathing. Parts of the prefrontal cortex showed evidence of thinning in the older control participants but not in the older participants who meditated, thus suggesting meditation might offer protection from age-related neuronal loss.

Another observation was that that the extent of cortical thickening correlated with meditation experience. Experienced practitioners show a noticeable difference in their respiration rate when they are meditating compared with being at rest. The researchers used the size of this difference as a measure of meditating experience, and found that in one specific region in the inferior occipital-temporal visual cortex, experience correlated with cortical thickness.

Jeremy Gray, co-author on the study, said “What is most fascinating to me is the suggestion that meditation practice can change anyone’s grey matter. The study participants were people with jobs and families. They just meditated an average of 40 minutes each day, you don’t have to be a monk”.

The researchers’ report on the work cautions that longitudinal research is needed to confirm that meditation causes the effects it has been associated with here.
Lazar, S. W., Kerr, C. E., Wasserman, R. H., Gray, J. R., Greve, D. N., Treadway, M. T., McGarvey, M., Quinn, B. T., Dusek, J. A., Benson, H., Rauch, S. L., Moore, C. I. & Fischl, B. Meditation experience is associated with increased cortical thickness. NeuroReport, 16, 1893-1897.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

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