Brain Plasticity and Neurophysiological Correlates of Meditation in Long-Term Meditators: A 18Fluorodeoxyglucose Positron Emission Tomography Study Based on an Innovative Methodology

Objective: Previous studies evaluating neurophysiological correlates of long-term meditation are constrained by some methodological limitations. The objective of this study was to measure changes in the regional cerebral glucose metabolism during meditation using a novel methodological approach. Design: The present study was a part of a larger, nonrandomized, single-center open-label study. Setting/location: The study was conducted at the Department of Physiology and Department of Nuclear Medicine and Positron Emission Tomography. A dedicated place was set up as a yoga room, away from the positron emission tomography (PET) scanning room in the Department of Nuclear Medicine and Positron Emission Tomography, where meditators performed meditation in a peaceful environment in a sitting posture with eyes closed. The electroencephalography (EEG) was recorded to affirm the meditation objectively. Subjects: Twenty-four sets of PET scans were obtained at 2 different occasions (baseline and postmeditation within 40 min of 18 FDG [ 18 fluorodeoxyglucose] injection) from 12 apparently healthy, male, right-handed long-term meditators practicing Preksha meditation (since >5 years, at least 5 days a week) who were recruited from a well-established meditation center in Delhi. Outcome measures: Changes in the regional cerebral glucose metabolism during meditation versus baseline. Results: Regional cluster analysis showed significantly activated well-defined areas of fronto-parieto-temporal regions of the right versus left hemisphere during meditation. Interestingly, right homolog of Broca's area and right lentiform nucleus were hyperactive during meditation in all the meditators. Conclusions: Long-term meditation might potentially enhance the explicit functions of specific parts of the right hemisphere, possibly due to neuroplastic changes in the brain. Importantly, results of the current study are encouraging and show a novel methodological approach to acquire 18 FDG PET/CT (computed tomography) images. The study was registered at Clinical Trial Registry India (CTRI), CTRI/2009/091/000727.