A Review of Yoga and Meditation Neuroimaging Studies in Healthy Subjects

Abstract

Background:

Yoga and meditation are two ancient methods of physical and mental discipline known to have effects on mental well-being. Understanding the structural and functional brain changes associated with yoga and meditation has the potential to advance knowledge of how these methods work. This systematic review analyzes studies that explore the changes in various brain areas associated with the practice of yoga and meditation in healthy subjects.

Methods:

All English-language articles describing neuroimaging of yoga and meditation using standard databases were searched by two authors independently. Studies were included if they mentioned explicitly that yoga or meditation was used in one of their intervention arms. Studies that focused on yoga as a treatment and/or intervention for physical or mental disorders or that involved imaging only during cognitive tests were excluded.

Results:

A total of 47 studies were included in the review of which 23 were of functional magnetic resonance imaging (fMRI), 18 were of MRI (magnetic resonance imaging), and the remaining studies were of positron emission tomography (PET) and single-photon emission computed tomography (SPECT). Most studies compared long-term practitioners of yoga and/or meditation in apparently healthy individuals. Despite great variation in brain regions identified across the studies, the areas of the brain that most commonly showed changes included the prefrontal cortex, hippocampus, temporo–parietal cortex, and insular cortex. These changes were more marked in long-term practitioners, compared to novices. The differences could be related to the variation in individual techniques of yoga and meditation used across the studies as well as differences in the inclusion criteria with respect to duration of practice.

Conclusion:

Yoga and meditation cause structural and functional changes across the brain with regular practice. Further studies with standardization of methodology to include specific techniques of yoga and meditation and specified duration of practice will advance the knowledge base in this area further.