US researchers have used a specialist brain scanning technique, magnetic resonance spectroscopic imaging, which is effectively an MRI scan carried out at the molecular level to reveal the effects of yoga practice on the brain. Specifically, they have investigated how concentrations of the feel-good compound gamma-aminobutyric (GABA), an inhibitory neurotransmitter, change after regular practice of yoga postures.
Eric Jensen and colleagues at Harvard Medical School looked at eight subjects prior to and after one hour of yoga as well as eleven control subjects who read a book rather than undertaking the yoga exercises. Although the samples are very small, they saw a marked difference in GABA levels in the yoga practitioners compared to the readers. Their findings suggest that yoga, and perhaps other forms of exercise, should be investigated as a complementary treatment for depression and anxiety disorders, which are commonly associated with low levels of GABA.