Reduced age-associated brain changes in expert meditators: a multimodal neuroimaging pilot study

Abstract

Aging is associated with progressive cerebral volume and glucose metabolism decreases. Conditions such as stress and sleep difficulties exacerbate these changes and are risk factors for Alzheimer's disease. Meditation practice, aiming towards stress reduction and emotion regulation, can downregulate these adverse factors. In this pilot study, we explored the possibility that lifelong meditation practice might reduce age-related brain changes by comparing structural MRI and FDG-PET data in 6 elderly expert meditators versus 67 elderly controls. We found increased gray matter volume and/or FDG metabolism in elderly expert meditators compared to controls in the bilateral ventromedial prefrontal and anterior cingulate cortex, insula, temporo-parietal junction, and posterior cingulate cortex /precuneus. Most of these regions were also those exhibiting the strongest effects of age when assessed in a cohort of 186 controls aged 20 to 87 years. Moreover, complementary analyses showed that these changes were still observed when adjusting for lifestyle factors or using a smaller group of controls matched for education. Pending replication in a larger cohort of elderly expert meditators and longitudinal studies, these findings suggest that meditation practice could reduce age-associated structural and functional brain changes.

Figure 1

Results of the analyses on gray matter volume. T-values of the voxelwise regression analysis between the z-score maps of the 186 controls (corrected for education) and age were superimposed on brain surface views (a). Mean w-score values of the expert meditators corrected for age and education and using the elderly control group as the reference (b), and clusters of interest showing significantly higher values in the expert meditators (voxel-level p < 0.001 and FWE-corrected cluster-level p < 0.05) (c) were superimposed on brain surface views. Volume residuals in the 3 clusters of interest were plotted in the elderly expert meditators (orange) and in the controls (blue) of the elderly control group (d; residuals are corrected for age and education); of the entire control group against age (e; residuals are corrected for education). VMPF-ACC: ventromedial prefrontal and anterior cingulate cortex; TP: temporo-parietal.

Figure 2

Results of the analyses on gray matter glucose metabolism. T-values of the voxelwise regression analysis between the z-score maps of the 186 controls (corrected for education) and age were superimposed on brain surface views (a). Mean w-score values of the expert meditators corrected for age and education and using the elderly control group as the reference (b), and clusters of interest showing significantly higher values in the expert meditators (voxel-level p < 0.001 and FWE-corrected cluster-level p < 0.05) (c) were superimposed on brain surface views. Glucose metabolism residuals in the 3 clusters of interest were plotted in the elderly expert meditators (orange) and in the controls (blue) of the elderly control group (d; residuals are corrected for age and education); of the entire control group against age (e; residuals are corrected for education). VMPF-ACC: ventromedial prefrontal and anterior cingulate cortex; TP: temporo-parietal.