Rajyoga Meditation Experience Induces Enhanced Positive Thoughts and Alters Gray Matter Volume of Brain Regions: A Cross-sectional Study

Many studies on various meditation types have reported regional gray matter volume changes using voxel-based morphometric analysis of structural MRI, but there are no studies done on structural MRI of Rajyoga meditators. The objective of the present study is to analyze and compare gray matter volume changes of brain regions in meditators and non-meditators and further study the effects of meditation experience on alterations in various brain regions. These regions were then correlated and compared to positive thought scores of participants. Forty participants in each group (closely matched for age, gender, and handedness) were selected after obtaining their informed consent, and voxel-based morphometric analysis was carried out using their structural MRI scans. On voxel-wise comparison of the brain scans, meditators were observed to have significantly higher global gray matter volume and significant regional gray matter volume increases in the right superior frontal gyrus, left inferior orbitofrontal cortex, left inferior parietal gyrus, left posterior cerebellum, left middle temporal gyrus, bilateral precuneus, and cuneus. Additionally, long-term meditators particularly had significantly higher positive thinking scores compared to non-meditators. On multiple regression analysis, gray matter volume of the left superior parietal gyrus and left inferior parietal gyrus had a positive association, whereas the left posterior cerebellum had a negative association with hours of meditation experience. With the positive thoughts score, a significant relationship was found in the right superior temporal gyrus in meditators. These findings indicate that Rajyoga meditation experience/practice enhances gray matter volume of specific brain regions and positive thoughts.