Neurophysiology of Meditation

By simple definition, meditation is engagement in contemplation, especially of a spiritual or devotional nature. To elaborate further, meditation is an attempt to concentrate mind on a single form or an idea or an aspect of divinity at the exclusion of all other forms, thoughts, and ideas. The mind is focused inwards, and this effort of concentration acts as a stimulus to gain access to knowledge of 'object of meditation'. The aspirant makes an attempt to minimize perceptions through senses - inputs through special senses like touch, sight, hearing, etc. - by detaching mind from sense organs in the brain. This helps in controlling restlessness of mind, in favour of inner contemplation. The mind, as if, is made still. Meditation may be, therefore, taken as a 'passive' activity! But is it really so?

Tremendous changes observed in the human brain and nervous system during mediation run contrary to this belief of 'passivity' attached to meditation. Unprecedented progress and research in neurobiology, investigative neurology, and study of neurotransmitters in the last two decades has given a great fillip to the study of neuro-physiology of Meditation and Yoga. Altered State of Consciousness can be brought about by hypnosis, drugs (e. g. LSD), sleep, etc., but here we are trying to study a state specific science of altered consciousness brought about by meditation alone.

We shall attempt to review the progress in neurobiology in the recent years. An attempt is made to throw light on this new and fascinating subject. The terms used are technical, but, as far as possible, an attempt is made to simplify the description.

This attempt to explain the neurophysiology of meditation is purely hypothetical.

One of the ways to control physiological reactions to psychological stimuli is meditation, Yoga, Zen Buddhism etc. The scientists take Transcendental Meditation (TM) as the uniform technique, and base their observations on the study of the subjects engaged in this form of meditation. In summing up the results the scientists have come to conclusion that the effect of meditation is a "wakeful, hypo-metabolic state".

They have found that:

1) Yogis could slow both heart rate and rate of respiration,

2) Yogis could slow the rate of metabolism as confirmed by decreased oxygen consumption and carbon-di-oxide output.

3) Electro-Encephalo-Gram (EEG - recording of brain activity) in Yogis showed changes of calmness in the form of "alpha rhythm" during both eyes closed and eyes open recordings.

4) Their skin resistance to electric stimulation was increased (indicating increased tolerance to external stimuli).

Our usual 'defence-alarm' reaction to emotional and physical stress is in the form of "fright, flight, and fight" mediated through over-secretion of certain neuro-transmitters and neuro-modulators, namely adrenaline and dopamine by way of stimulation of sympathetic nervous system. Under the influence of these chemicals and hormones, we reflexively become panicky or aggressive, our blood pressure rises. Thus stress and anxiety is the end result if we allow our natural age-old sympathetic reactions to act and to come to surface. We try to run away, become fearful, or fight the situation. But today these 'defence-alarm' reactions have no place in our lives. Rather, they should be replaced by more calm and serene reactions of equanimity and fearlessness. The need is to just 'face the brute, and it will go away'. Such desirable reactions of non-aggression and peaceful attitude are generated by Yoga and meditation. (Read More .... )