Long-term Buddhist practitioners can self-induce sustained, high-amplitude gamma-band oscillations and phase-synchrony in the brain during meditation, as measured by electroencephalography. These EEG patterns differ from those of non-practitioners, especially over lateral frontoparietal electrodes. Before meditation, practitioners already show a higher ratio of gamma-band activity (25-42 Hz) to slow oscillatory activity (4-13 Hz) over medial frontoparietal electrodes compared to controls. This ratio increases sharply during meditation across most of the scalp and remains elevated afterward. The findings suggest that mental training involves temporal integrative mechanisms and may produce both short-term and long-term neural changes.
Aging typically shrinks brain volume and lowers glucose metabolism, with stress and poor sleep accelerating these changes. In a pilot study comparing 6 elderly expert meditators with 67 elderly controls, the meditators showed greater gray matter volume and/or FDG metabolism in several brain regions: the ventromedial prefrontal and anterior cingulate cortex, insula, temporo-parietal junction, and posterior cingulate cortex/precuneus. These same regions were most affected by age in a larger control group of 186 people aged 20 to 87. The differences persisted after adjusting for lifestyle factors and education. The findings suggest that lifelong meditation might reduce age-related brain decline, but larger and longitudinal studies are needed.