The Bentov bio-medical model, as described in a book by Lee Sannella, M.D., entitled: Kundalini-Psychosis or Transcendence, states that the standing acoustical waves are the result of the altered rhythm of heart sounds which are occasioned by prolonged practice of meditation, and which set up sympathetic vibrations in the walls of the fluid filled cavities which comprise the third and lateral ventricles of the brain.