Rajyoga meditation induces grey matter volume changes in regions that process reward and happiness

M G Ramesh Babu,Kiranmai S Rai,Brijesh Sathian,Prakashini Koteshwara,Rajagopal Kadavigere

doi:10.1038/s41598-020-73221-x

Abstract

Studies provide evidence that practicing meditation enhances neural plasticity in reward processing areas of brain. No studies till date, provide evidence of such changes in Rajyoga meditation (RM) practitioners. The present study aimed to identify grey matter volume (GMV) changes in reward processing areas of brain and its association with happiness scores in RM practitioners compared to non-meditators. Structural MRI of selected participants matched for age, gender and handedness (n = 40/group) were analyzed using voxel-based morphometric method and Oxford Happiness Questionnaire (OHQ) scores were correlated. Significant increase in OHQ happiness scores were observed in RM practitioners compared to non-meditators. Whereas, a trend towards significance was observed in more experienced RM practitioners, on correlating OHQ scores with hours of meditation experience. Additionally, in RM practitioners, higher GMV were observed in reward processing centers—right superior frontal gyrus, left inferior orbitofrontal cortex (OFC) and bilateral precuneus. Multiple regression analysis showed significant association between OHQ scores of RM practitioners and reward processing regions right superior frontal gyrus, left middle OFC, right insula and left anterior cingulate cortex. Further, with increasing hours of RM practice, a significant positive association was observed in bilateral ventral pallidum. These findings indicate that RM practice enhances GMV in reward processing regions associated with happiness.

Highlights

Studies provide evidence that practicing meditation enhances neural plasticity in reward processing areas of brain
A trend towards significant positive association was observed (Spearman’s correlation coefficient = 0.276, p = 0.084) when Oxford Happiness Questionnaire (OHQ) scores were correlated with normalized hours of meditation experience (Fig. 1)
The interesting finding in the present study is the significant positive association of grey matter volume (GMV) in bilateral ventral pallidum (VP) with Rajyoga meditation (RM) experience, which may indicate that RM practice may contribute to the automatic mind states of developing positive motivation and experience of reward

Summary

Introduction

Studies provide evidence that practicing meditation enhances neural plasticity in reward processing areas of brain. The present study aimed to identify grey matter volume (GMV) changes in reward processing areas of brain and its association with happiness scores in RM practitioners compared to non-meditators. With increasing hours of RM practice, a significant positive association was observed in bilateral ventral pallidum These findings indicate that RM practice enhances GMV in reward processing regions associated with happiness. The NAcc is known as ‘‘pleasure center’’ in the brain and is known to generate positive hedonic states regardless of any source of pleasure-inducing stimuli manipal.edu Such as monetary reward, social reward, food, water, sex, drugs, etc. A study on SOHAM meditation suggests that higher grey matter density in VP is associated with reward processing and positive m otivation[17] Apart from these cortical and sub-cortical regions that involve in reward process, the precuneus engages in different other processing such as reward-based decision-making task. Several studies reported the importance of precuneus, which has a role in the subjective experience of happiness, including emotional and cognitive components and subjective well-being[1,2,20,21]

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