An out-of-body experience was repeatedly triggered by stimulating the posterior part of the right superior temporal gyrus in a patient with implanted electrodes for tinnitus. Brain scans showed activation at the right temporoparietal junction, specifically at the angular-supramarginal gyrus junction and the superior temporal gyrus-sulcus, as well as the right precuneus and posterior thalamus extending into the superior vermis. The authors suggest that activation in these regions is the neural basis for the feeling of disembodiment during an out-of-body experience.
A review of 34 neuroimaging studies of yoga practitioners finds consistent increases in gray matter volume in the insula and hippocampus, increased activation in prefrontal cortical regions, and functional connectivity changes mainly within the default mode network. Variability in findings partially reflects different yoga styles and sample size limitations. Direct comparator groups such as physical activity are rarely used. The authors discuss hypotheses on the underlying neurobiology of yoga's potential beneficial effects.
Experienced yoga practitioners show long-term decreases in glucose metabolism in the medial temporal cortex, striatum, and brainstem compared to yoga-naive controls, with greater decreases linked to more years of regular practice. A single yoga practice increased metabolism in the cerebellum. No differences were found in brain structure or resting-state connectivity. The findings suggest that regular yoga practice may induce lasting metabolic changes in brain regions involved in memory, emotion, and motor control, but a prospective study is needed to confirm causality.
A 12-week yoga intervention, compared with indoor cycling, improved interoceptive awareness and perceived cognitive function in healthy female beginners. Thirty healthy women (average age 28.4 years) were randomly assigned to yoga or cycling. Yoga participants reported higher interoceptive awareness and better cognitive functioning than the cycling group. No significant differences in glucose metabolism, synaptic density, or gray matter volume were detected between groups. The cycling group showed increased relative glucose metabolism in the parahippocampal/fusiform gyrus and cerebellum. The authors suggest that longer or more frequent yoga practice may be needed to detect cerebral metabolic or morphologic changes at the macroscopic level.