Chanting OM aloud produces a sensation of vibration, and the authors note this has the potential to stimulate the through its auricular branches. Whether anything measurable follows in the brain had not been explored. Twelve volunteers went into a scanner to find out.
Things quieted down rather than lighting up. Compared with rest, chanting produced significant in both orbitofrontal cortices, the anterior cingulate, the parahippocampal gyri, the thalami and the hippocampi, plus the right . No region showed significant activation, and saying a long produced neither.
A sensation of vibration accompanies audible OM chanting, and that sensation is the starting point. The authors note it has the potential for vagus nerve stimulation through the auricular branches of that nerve, and the brain effects of chanting had yet to be explored.
The design is small and careful. Twelve right-handed healthy volunteers, nine of them men, chanted in the scanner, pronounced a sustained ssss as a comparison, and rested, with the images analyzed in SPM5.
Against the resting brain state, chanting produced significant bilateral deactivation in the orbitofrontal cortices, the anterior cingulate, the parahippocampal gyri, the thalami and the hippocampi, and the right amygdala deactivated as well. No significant activation appeared anywhere.
The control condition is what gives this weight. Neither activation nor deactivation occurred in those regions during the ssss condition. The authors read the pattern as limbic deactivation and note that similar observations come from vagus nerve stimulation used in depression and epilepsy. On that basis they argue for a potential clinical role, which is what a pilot study can propose and not what it can show.
wat. Chanting OM deactivated limbic regions, while making a comparable sound did nothing.
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It gives a practice described in experiential language a measurable signature, and the control condition is what makes that signature mean anything.
How do we know?
Kalyani and colleagues scanned twelve right-handed healthy volunteers with fMRI, comparing audible OM chanting against pronouncing ssss and against rest, and analyzed the images in SPM5.
What is still unknown
Twelve people, nine of them men, in a pilot study; the vagus nerve explanation is the authors’ proposed mechanism rather than something they measured.
Learn something?
Where to next
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