Head-Heart Entrainment: A Preliminary Survey
R. McCraty, W. A. Tiller, M. Atkinson
Paper presented at the Key West Brain-Mind, Applied Neurophysiology, EEG Biofeedback 4th Annual Advanced Colloquium, Key West, FL, Feb. 1996.For a PDF version of the complete paper, click here.
This preliminary survey deals with experimental observations on the degree of entrainment exhibited between heart rate variability (HRV), respiration and electroencephalograph (EEG) recordings for 5 subjects, trained in the use of a particular inner self-management technique, as they change their mode of heart function through various states of order. As the heart approaches its first major ordered mode of functioning (entrainment), both the sympathetic and parasympathetic branches of the autonomic nervous system shift their power into the mid frequency range (~ 0.1 Hz) in the HRV power spectrum which is associated with the baroreceptor feedback loop between the heart and brain. One then sees frequency pulling of the respiratory system towards this mid frequency range, until frequency-locking of the HRV waveform and respiration rate occurs. Thereafter, the signal amplitude in the ~0.1 Hz range of the brainwaves begins to increase significantly. Strong cross-correlation functions are found to exist between these pairs of biological oscillators. However, the brain wave signals from different areas of the brain don’t all frequency-lock with the baroreceptor signal. The auxiliary data indicates that there is much hidden complexity yet to be elucidated. Evoked potential data reinforces some of the major findings.