Cerebral blood flow changes associated with different meditation practices and perceived depth of meditation.

Our goal in this study was to advance the understanding of the neural pathways of meditation by addressing the cerebral blood flow (CBF) responses associated with two different meditation practices performed by the same individuals and how such changes related to the "stress" circuits in the brain. Ten experienced meditators performed two types of meditation, a "focused-based" practice and a "breath-based" practice. Subjects were scanned using perfusion functional magnetic resonance imaging (fMRI) during a baseline state, both meditation states, and a post meditation baseline state. Using general linear model, we found that the frontal regions, anterior cingulate, limbic system and parietal lobes were affected during meditation and that there were different patterns of CBF between the two meditation states. We observed strong correlations between depth of meditation and neural activity in the left inferior forebrain areas including the insula, inferior frontal cortex, and temporal pole. There were persistent changes in the left anterior insula and the precentral gyrus even after meditation was stopped. This study revealed changes in the brain during two different meditation practices in the same individuals and that these changes correlated with the subjective experiences of the practitioners.