These heat thermography photos (view larger) were taken of Jonathan Goldman as he began (left) and finished (right) a set of vocal harmonics. Thermography measures changes in skin temperature and could indicate changes in brain activity. "It is my belief that self-created sounds can trigger different chemicals such as melatonin in the brain," Goldman writes. He also suggests that these photos may demonstrate the activation of chakra energies. For more on the photo experiment, click here(1).

1. http://www.healingsounds.com/research/heat-thermography.asp