Increased Grey Matter Associated with Long-Term Sahaja Yoga Meditation: A Voxel-Based Morphometry Study

Abstract

ObjectivesTo investigate regional differences in grey matter volume associated with the practice of Sahaja Yoga Meditation.DesignTwenty three experienced practitioners of Sahaja Yoga Meditation and twenty three non-meditators matched on age, gender and education level, were scanned using structural Magnetic Resonance Imaging and their grey matter volume were compared using Voxel-Based Morphometry.ResultsGrey matter volume was larger in meditators relative to non-meditators across the whole brain. In addition, grey matter volume was larger in several predominantly right hemispheric regions: in insula, ventromedial orbitofrontal cortex, inferior temporal and parietal cortices as well as in left ventrolateral prefrontal cortex and left insula. No areas with larger grey matter volume were found in non-meditators relative to meditators.ConclusionsThe study shows that long-term practice of Sahaja Yoga Meditation is associated with larger grey matter volume overall, and with regional enlargement in several right hemispheric cortical and subcortical brain regions that are associated with sustained attention, self-control, compassion and interoceptive perception. The increased grey matter volume in these attention and self-control mediating regions suggests use-dependent enlargement with regular practice of this meditation.

Gray Matter and Functional Connectivity in Anterior Cingulate Cortex are Associated with the State of Mental Silence During Sahaja Yoga Meditation

“…In our previous morphometry study (Hernandez et al, 2016), bilateral AI was shown to have larger GMV in longterm meditators and these gray matter clusters partially overlapped with the ones which were shown to be enhanced in FC with rACC/mPFC in this study. The role of AI in structure and function in association with SYM meditation is in consonance with the role of AI already described in many other meditation techniques, presumably due to the interoceptive function mediated by this area (Farb et al, 2007;Luders et al, 2012;Lutz et al, 2008Lutz et al, , 2009.…”

“…Although the meditators of this study had around 7.8% larger GMV than the healthy controls in rACC/mPFC, this difference was not statistically significant (p = 0.3) and therefore was not observed in our previous VBM paper (Hernandez et al, 2016). Although rACC/mPFC activation has been observed in many fMRI studies of meditation, (Fox et al, 2016;Hoelzel et al, 2007;Xue et al, 2011), this is not the case for morphometry studies of meditation (for a review of see (Fox et al, 2014).…”

“…The 23 meditators and 23 nonmeditators who participated in this study are identical to those reported in our Voxel-Based Morphometry (VBM) study (Hernandez et al, 2016).…”

“…The GMV comparison between meditators and nonmeditators has been published elsewhere (Hernandez et al, 2016). In this study, our focus was on the correlation between the depth of mental silence and the structural imaging data and the FC data during the MS.…”

“…In the last and deepest state of meditation, relatively weaker activation remained in right inferior frontal gyrus extending to right anterior insula (AI) and right middle-superior temporal lobe, with the right inferior frontal gyrus activation being specifically correlated with the depth of mental silence. In the structural MRI study, gray matter volumes (GMV) of 23 long-term meditators of SYM were compared to those of a group of non-meditators matched on age, gender, and education level (Hernandez et al, 2016). An ANCOVA with total intracranial volumes, gender, and age as nuisance covariates showed that overall whole brain GMV was significantly different between groups (F = 10.445, p = 0.002), due to GMV being on average 7% larger in meditators.…”