Taken a head trip lately? Feel like giving the old brain a buzz? The hippies who coined these graphic expressions were referring to the state of ‘bum bum’, the drug-induced flight of fancy, the fascinating world of LSD or hemp hallucinations. But a generation before the drug culture, Canadian neurosurgeon Wilder Penfield was mind tripping in a way that is even more bizarre. Working with patients who had neurological disorders that made brain probing necessary, Penfield stimulated different parts of the cerebral cortex with minute electrical impulses. These stimulation studies allowed him to demonstrate the existence of pathways that carry information to the brain from various parts of the nervous system. In particular, Penfield was able to identify the different brain regions associated with certain parts of the body. As he moved electrodes to assorted locations on the brain surface, specific parts of the body would twitch as if in answer to a normal command from the brain. At other times, bodily sensations would be aroused exactly as if that organ had been activated by some sense stimulus from the external environment. When the visual or auditory cortex was stimulated, the patient saw light flashes or heard buzzing or musical tones. In this way Penfield was able to map those areas of the brain directly governing sensations and muscular activity in the various limbs and organs.

This area is known as the sensorimotor cortex and as we move across its surface we come to the areas associated with the face, neck, thumb, index finger, middle finger, ring finger, little finger, and so on, down to the toes.

This is where we make the connection between the latest neurosurgery and the meditational technique of yoga nidra, a yogic practice evolved from the most ancient tantric scriptures. Yoga nidra is a systematic method for inducing complete physical, mental and emotional relaxation. The state of yoga nidra is one of relaxation so deep that we seem to be asleep to the outside world. If you have ever practiced this technique, then you’ll recognize the signposts on the sensorimotor cortex as precisely those parts of the body through which your awareness passes during the ‘rotation of consciousness’.

“Rotation of awareness by taking a trip through the body… Right hand thumb, second finger, third finger, fourth finger, fifth finger, palm, wrist, elbow, shoulder, armpit, right waist, right thigh, kneecap, calf muscle, ankle, heel, sole, big toe, second toe, third toe, fourth toe, fifth toe…”

Consciousness is no incorporeal phantasm, but a fine mesh that encompasses the body as surely as the gossamer glory of the spider’s web is spun from her abdomen. The brain is the physical mediator of consciousness, linking mind, body and emotions into one harmonious unit. The neurosurgeon affects the body by stimulating the brain. The practitioner of yoga nidra begins at the other end of the nerve pathway by heightening awareness of the body. The progressive movement of awareness through the parts of the body not only brings physical relaxation, but also relaxes the sensorimotor cortex of the brain. If we begin at the toes and end with the tongue, we clear all the nerve pathways to the brain, both those governing physical activity and those concerned with incoming information. At the same time we make a total run of the brain surface from inside out. In this way, yoga nidra relaxes the mind by using the mind to relax the body.

In some forms of yoga nidra the rotation of consciousness does begin at the toes, but it is more common to start with the right hand thumb. Just as it is easier to travel along a much used highway than a rarely trodden cart track, so the more often a nerve impulse travels along a particular pathway the easier it is to activate that pathway in the future. Because the connections with the hands are frequently used, during yoga nidra it is relatively easy to develop mental awareness of the hands. The hands are also among the most sensitive of man’s organs of action, with a greater number of nerve endings in the palms and fingers to transmit messages to the brain. For these reasons most people find it easier to develop awareness of the hands than most other parts of the body. This is especially true for beginners in yoga nidra. When you refer to the motor homunculus, you will also note the disproportionately large amount of brain space concerned with the hands and fingers. This region is almost as large as for the entire remainder of the body from the wrist to the toes ! Beginning with the hands is not only easier, but also affects a huge area of the brain, giving an initial impetus to the process of relaxation.

Scattered through the periphery of the body are numerous cells which are sensitive not only to normal electrical nerve impulses, but also to mechanical stimulation such as pressure or touch, temperature and so on. Although we do not usually think of them as such, these cells (proprioceptors) are actually tiny sense organs that are continually gathering information from all parts of the body and sending it to specified sites deep in the brain. Neurologists have located these focal points, the most important of which are those concerned with food and water intake, heat and cold, pain and pleasure.

Once again it is impossible to ignore the connection between the discoveries made by today’s brain explorers and those made by the seers who long ago evolved the practice of yoga nidra. After relaxation of the sensorimotor surface of the brain, the practice of yoga nidra moves our attention from the separate outlying areas of the body to arousal of feelings that seem to emanate from the core of our organism yet bathe the body as a whole. As we awaken the sensations of heat and cold, pain and pleasure, we stimulate those centres of the brain responsible for maintaining harmony between our inner and outer environments. Each of these centres has its reciprocal for balancing our basic drives, and the pairing of these sensations in yoga nidra helps this balance as well as bringing normally unconscious functions under control.

Characteristically the first of these feelings to be awakened is that of heaviness… “You are feeling so heavy that you are sinking into the floor.” Although this sensation of heaviness has not yet been localized in the brain, it is a whole body sensation that is a product of deep muscular relaxation. At the same time, if relaxation is not complete, awakening the feeling of heaviness acts as a command from the brain encouraging the muscles to ‘let go’, to drop their burden of upholding the body. The weight of the body is then deposited on the floor, giving the impression that we are sinking through the surface on which we are lying.

As the feeling of heaviness intensifies, so it is superseded by a sensation of lightness… “Awaken a sensation of lightness and weightlessness in all parts of the body… Your body feels so light… that it seems to be floating away from the floor.”

To induce a sensation of lightness is not an arbitrary choice but a direct outcome of the way the brain functions. When a nerve cell (neurone) fires, that is, when it transmits an impulse, this is registered in the brain. However, if the cell continues to fire for some time, the message is no longer acknowledged by the brain, it becomes a constant feature to the brain’s environment as it were. You can verify this particularly with smell. When you first enter a room where incense has been burning, you are very much aware of the perfume. However, after you have been in the room for some time, you no longer notice the incense. Researchers have called this phenomenon habituation. The brain becomes habituated, accustomed to the stimulus, and ceases to register it as important.

It would seem that this is what happens during yoga nidra. While focusing awareness on the sensation of heaviness throughout the body, the nerves fire a volley of impulses to the brain. After some time, however, the brain ignores these impulses, it breaks the connection with the body. The feeling of lightness then arises spontaneously and our awareness floats free of its physical vehicle. Now, rather than physical sensations shaping our consciousness, our consciousness can determine what will be felt by the body.

Stimulation of these homeostatic mechanisms moves us right into the midbrain, and brings greater awareness of the region known as the hypothalamus. This region is the primary regulator of the autonomic (involuntary) nervous system which is intimately bound up with the glands and emotions. Electrical stimulation of certain parts of the hypothalamus gives rise to the emotions of rage, aggression and fear. Most of us find these negative feelings much stronger and harder to control than positive emotions. Nevertheless, in advanced yoga nidra we are asked to submit voluntarily to these threatening emotions, while still maintaining a state of deep relaxation.

This brings into simultaneous operation nerve circuits that, under normal circumstances, never operate at the same time. Thus a new circuit is established incorporating these two apparently irreconcilable states in such a way that relaxation predominates.

In. this way, yoga nidra allows us to experience mental control of our emotions and senses (at least temporarily) and establishes fresh neuronal patterns that we can fall back on to carry this control into our normal waking lives.

The end state of the practice of yoga nidra is ‘psychic sleep’ or sleep in a state of inner awareness. It is a state on the borderline between sleep and wakefulness that allows contact with the subconscious and unconscious mind. Next month we will discuss this state in terms of its psychological and spiritual implications.

(Courtesy Yoga Magazine, January, 1979)

Last month the author discussed the psycho-physiological implications of this relaxation/meditation technique. An important connection between the latest brain research and yoga nidra was mapped out showing the signposts of the sensorimotor cortex as being precisely those parts of the body through which the awareness passes in yoga nidra during the period of ‘rotation of consciousness’. Thus it was shown how the neurosurgeon affects the body by stimulating the brain, while the practitioner of yoga nidra begins at the other end of the nerve pathway by heightening awareness of the body. This month the author takes up the psychological and spiritual implications of this technique. (Editor.)

The end state of yoga nidra is psychic sleep or sleep in the state of inner awareness. It is a state on the borderline between sleep and wakefulness that allows contact with the subconscious and unconscious mind where we have stored all our past memories. Those experiences that were particularly painful have been pushed deep into the unconscious, beyond remembrance. However, they are still alive and are the source of our fears and obsessions. Also in the unconscious are our instinctive desires, constantly competing for expression and satisfaction through the conscious mind. We can look at tension as the accumulation of repressed energy that powers those drives and desires which are denied conscious satisfaction. During yoga nidra these frustrations and thwarted desires are given expression so that tension is reduced and the energy behind them is freed for use in other directions. This process also takes place during normal sleep when we dream.

In their search for the memory banks in the brain, neurologists have failed to pin down any one area that is the storehouse of our memories. However, the Canadian neurosurgeon Wilfred Penfield found that when some secretions of the temporal cortex were stimulated, the patient recalled apparently full blown memory sequences- an evening at a concert, a childhood experience and so forth. Repeated stimulation of the same spot would evoke the same recollections each time. It is now thought that particular sets of brain circuits and firing patterns form the relevant code for memory, but any single memory is not localized in a single network. Rather, it will be duplicated in both hemispheres and many times over.

Once the brain has chanced upon a particular circuit, perhaps as a result of spontaneous, random firing as in dreaming, then a particular memory sequence and its ensuing emotional state will follow almost of necessity. The brain flips into particular states which will then run their course, unrolling otherwise suppressed memory sequences as they proceed. The specific instruction must be to fire particular circuits from which the rest will follow. This is exactly what happens in yoga nidra. Yoga nidra brings us to a state of self induced dreaming- with a difference. Regular dreams are composed simply of a random selection of impulses. During yoga nidra we create our own dream by visualizing a wide variety of symbols that have powerful and universal significance.

“A number of different things will be named and you should try to develop a vision of these things on all levels- feeling, awareness, emotion, imagination…

Shiva lingam, standing Christ, flickering candle, weeping willow tree, dead body, coloured clouds gathering, starlit night, full moon, setting sun, golden spider web, cross over a church, cold winter’s day, temple bell ringing, monk with shaven head, Buddha in repose, a yogi sitting deep in meditation.”

More importantly, experience has shown that just like Penfield’s electrodes, these ‘rapid images’ also spark totally unrelated memory sequences. The temporal cortex where these memories are encoded has links with the hypothalamus, which governs the emotions, so that every memory comes with an emotional charge. Some recollections may seem trivial. Others have emotional impact that would be overwhelming if recalled under normal circumstances, but which becomes manageable in the deeply relaxed state of yoga nidra. In this way many kinds of tension are released and the mind is cleaned of disturbing material. Sometimes these are very positive memories, but either way, these recollections have a very powerful effect that can change one’s whole life. When we regularly review the contents of the unconscious in this way, we greatly reduce anxiety and bring our inner being into greater harmony.

Yoga nidra is not just a matter of emotional hygiene- it is also a spiritual practice. It is a method of pratyahara or sense withdrawal which reduces our awareness of the outside work! and our physical existence. Paradoxically, this is accomplished mainly by heightening awareness of the body during the rotation of consciousness through the different limbs and organs. A possible explanation for why this is so may be made in terms of brain mechanisms.

When a nerve receives information, an electrical impulse is discharged. The time taken for an impulse to pass the full length of the neurone varies, but the time taken to pass any particular point on the cell membrane is about one millisecond. However, for an equal period after the impulse has passed, the cell is incapable of sending a second signal. By intensifying our awareness of a particular part of the body, we can induce a sensation that causes the cells in that part of the body to fire an impulse to the brain. Immediately after, there is a split second in which the cell cannot send more information. The brain’s connection with the outside world via that cell is then cut off- there is an instant of numbness, withdrawal, pratyahara.

Of course, the connection is soon restored, but by this time one’s awareness has jumped to another part of the body. That cell is effectively switched off for the duration of the practice, for the connection is not fully reopened; the brain’s selective tuning mechanism screens out any later messages. You can personally experience this selective tuning in operation in a crowded room where several people are talking at the same time. Close your eyes and listen to just one person speaking, then tune him out and listen to another person. Although we are not aware of it, we are tuning ourselves in this way all the time. Understanding this mechanism in action adds an extra dimension to Swami Satyananda Saraswati’s definition of yoga nidra as “relaxation by creating one pointedness of mind”.

Once attention has been withdrawn from the body, the consciousness is then rotated through various thoughts and feelings, causing withdrawal from these also. It is interesting to note that the area thus brought into play, the hypothalamus, is immediately adjacent to the pineal and pituitary glands. These are the two most important endocrine glands in the human organism, both of which secrete hormones that affect our state of consciousness. The pineal gland is otherwise known as the ‘third eye’ and was designated by the philosopher Descartes as the seat of the soul. To yogis it is known to be the physical counterpart of ajna chakra. This is one of our chief psychic centres, acting as a channel for the higher forces which guide our spiritual growth. Its full awakening marks the elevation of our consciousness from the emotional and intellectual planes to the psychic realms. The pituitary is the master gland of the body, linking the nervous and hormonal systems and influencing all metabolic and emotional reactions. In the terms of yoga, this gland is the physical correspondent of sahasrara chakra, the doorway to enlightened consciousness expanding to infinity. The awakening of sahasrara marks the passage from the merely psychic to the truly spiritual- once sahasrara has opened we become fully human.

These two chakras are vortices of psychic energy or prana and, like other meditation practices, yoga nidra is very much concerned with the generation and balancing of pranic energy in order to induce higher states of consciousness. Some yogic scriptures even go so far as to say that prana is consciousness. Although consciousness is beyond mind and mind is beyond the brain, there are links between physical brain processes and pranic flow. The chemical composition of the fluids in and around nerve cells is such that there is an uneven distribution of positively charged sodium and potassium ions across the cell membrane. When the cell fires, there is not only a travelling electrical impulse, but a flow of ions also. This results in a reversal of the cell’s electric charge together with a release of energy. Scientists have accumulated a great deal of evidence that ions are the physical vehicle of prana. It would seem that the flow of consciousness in yoga nidra initiates a flow of ions, and hence a flow of pranic energy.

“Awareness of parts of the body… the consciousness should move around the body and keep moving … as it moves it changes into prana, the vital energy, in the form of a current of energy.”

The full significance of this can be appreciated in view of the often stated fact that we use only one tenth of the brain’s potential. In opening up the frontiers of the brain, neurologists have found vast, diffuse zones that do not seem to be tied to any single, definable function. Surgical removal of large amounts of brain tissue from these areas has also been carried out without making any apparent difference to the patient’s memory or ability to function. One of the main features of the human brain is the existence of many duplicate pathways and circuits, and, except for the speech centre, control centres in one hemisphere have a duplicate in the other. This is why, when some part of the brain is diseased or injured, partial or total replacement of lost functions can occur. It becomes obvious then, that there is a considerable redundancy of function even in those areas which are currently active in most human beings, and an enormous spare capacity as yet untapped.

In this age of parapsychology and Kirlian photography we are just becoming aware of our energy body, pranamaya kosha, and the supernormal capability released in the human brain by the proper direction of psychic energy. It is more than just a vague possibility that much of this dormant potential is connected with the more subtle energy sheaths of the human organism.

In his book ‘The Conscious Brain’, neurologist Stephen Rose comments:

“Our cranial capacity or cell number may not be so different from the early homo sapiens, but our environments – our forms of society – are very different and hence so too is our consciousness which also means that so too are our brain states. The connectivity, if nothing else, of the brains of twentieth century humans cannot be identical with that which characterized our ancestors.”

The systematic passage of awareness through the brain during yoga nidra is inseparable from the flow of both nervous and pranic energy. As well as clearing old pathways, every time one practices yoga nidra this energy flow forges new connections between brain circuits, and lights up the dark, inactive areas of the brain. Yoga nidra is thus a tool for both physical and spiritual evolution, withdrawing our consciousness from its preoccupation with the outer world and bringing many unconscious functions into the light of conscious control. Yogis have long maintained that the process of self realization is one in which the brain is inundated with subtle energy – sahasrara chakra deluged with kundalini shakti. Yoga nidra is one of the most potent means evolved from tantra for the ‘rewiring’ of the brain that is the prerequisite of this ultimate enlightenment.

(Courtesy Yoga Magazine, February 1979)

Taken a head trip lately? Feel like giving the old brain a buzz? The hippies who coined these graphic expressions were referring to the state of ‘bum bum’, the drug-induced flight of fancy, the fascinating world of LSD or hemp hallucinations. But a generation before the drug culture, Canadian neurosurgeon Wilder Penfield was mind tripping in a way that is even more bizarre. Working with patients who had neurological disorders that made brain probing necessary, Penfield stimulated different parts of the cerebral cortex with minute electrical impulses. These stimulation studies allowed him to demonstrate the existence of pathways that carry information to the brain from various parts of the nervous system. In particular, Penfield was able to identify the different brain regions associated with certain parts of the body. As he moved electrodes to assorted locations on the brain surface, specific parts of the body would twitch as if in answer to a normal command from the brain. At other times, bodily sensations would be aroused exactly as if that organ had been activated by some sense stimulus from the external environment. When the visual or auditory cortex was stimulated, the patient saw light flashes or heard buzzing or musical tones. In this way Penfield was able to map those areas of the brain directly governing sensations and muscular activity in the various limbs and organs.

This area is known as the sensorimotor cortex and as we move across its surface we come to the areas associated with the face, neck, thumb, index finger, middle finger, ring finger, little finger, and so on, down to the toes.

This is where we make the connection between the latest neurosurgery and the meditational technique of yoga nidra, a yogic practice evolved from the most ancient tantric scriptures. Yoga nidra is a systematic method for inducing complete physical, mental and emotional relaxation. The state of yoga nidra is one of relaxation so deep that we seem to be asleep to the outside world. If you have ever practiced this technique, then you’ll recognize the signposts on the sensorimotor cortex as precisely those parts of the body through which your awareness passes during the ‘rotation of consciousness’.

“Rotation of awareness by taking a trip through the body… Right hand thumb, second finger, third finger, fourth finger, fifth finger, palm, wrist, elbow, shoulder, armpit, right waist, right thigh, kneecap, calf muscle, ankle, heel, sole, big toe, second toe, third toe, fourth toe, fifth toe…”

Consciousness is no incorporeal phantasm, but a fine mesh that encompasses the body as surely as the gossamer glory of the spider’s web is spun from her abdomen. The brain is the physical mediator of consciousness, linking mind, body and emotions into one harmonious unit. The neurosurgeon affects the body by stimulating the brain. The practitioner of yoga nidra begins at the other end of the nerve pathway by heightening awareness of the body. The progressive movement of awareness through the parts of the body not only brings physical relaxation, but also relaxes the sensorimotor cortex of the brain. If we begin at the toes and end with the tongue, we clear all the nerve pathways to the brain, both those governing physical activity and those concerned with incoming information. At the same time we make a total run of the brain surface from inside out. In this way, yoga nidra relaxes the mind by using the mind to relax the body.

In some forms of yoga nidra the rotation of consciousness does begin at the toes, but it is more common to start with the right hand thumb. Just as it is easier to travel along a much used highway than a rarely trodden cart track, so the more often a nerve impulse travels along a particular pathway the easier it is to activate that pathway in the future. Because the connections with the hands are frequently used, during yoga nidra it is relatively easy to develop mental awareness of the hands. The hands are also among the most sensitive of man’s organs of action, with a greater number of nerve endings in the palms and fingers to transmit messages to the brain. For these reasons most people find it easier to develop awareness of the hands than most other parts of the body. This is especially true for beginners in yoga nidra. When you refer to the motor homunculus, you will also note the disproportionately large amount of brain space concerned with the hands and fingers. This region is almost as large as for the entire remainder of the body from the wrist to the toes ! Beginning with the hands is not only easier, but also affects a huge area of the brain, giving an initial impetus to the process of relaxation.

Scattered through the periphery of the body are numerous cells which are sensitive not only to normal electrical nerve impulses, but also to mechanical stimulation such as pressure or touch, temperature and so on. Although we do not usually think of them as such, these cells (proprioceptors) are actually tiny sense organs that are continually gathering information from all parts of the body and sending it to specified sites deep in the brain. Neurologists have located these focal points, the most important of which are those concerned with food and water intake, heat and cold, pain and pleasure.

Once again it is impossible to ignore the connection between the discoveries made by today’s brain explorers and those made by the seers who long ago evolved the practice of yoga nidra. After relaxation of the sensorimotor surface of the brain, the practice of yoga nidra moves our attention from the separate outlying areas of the body to arousal of feelings that seem to emanate from the core of our organism yet bathe the body as a whole. As we awaken the sensations of heat and cold, pain and pleasure, we stimulate those centres of the brain responsible for maintaining harmony between our inner and outer environments. Each of these centres has its reciprocal for balancing our basic drives, and the pairing of these sensations in yoga nidra helps this balance as well as bringing normally unconscious functions under control.

Characteristically the first of these feelings to be awakened is that of heaviness… “You are feeling so heavy that you are sinking into the floor.” Although this sensation of heaviness has not yet been localized in the brain, it is a whole body sensation that is a product of deep muscular relaxation. At the same time, if relaxation is not complete, awakening the feeling of heaviness acts as a command from the brain encouraging the muscles to ‘let go’, to drop their burden of upholding the body. The weight of the body is then deposited on the floor, giving the impression that we are sinking through the surface on which we are lying.

As the feeling of heaviness intensifies, so it is superseded by a sensation of lightness… “Awaken a sensation of lightness and weightlessness in all parts of the body… Your body feels so light… that it seems to be floating away from the floor.”

To induce a sensation of lightness is not an arbitrary choice but a direct outcome of the way the brain functions. When a nerve cell (neurone) fires, that is, when it transmits an impulse, this is registered in the brain. However, if the cell continues to fire for some time, the message is no longer acknowledged by the brain, it becomes a constant feature to the brain’s environment as it were. You can verify this particularly with smell. When you first enter a room where incense has been burning, you are very much aware of the perfume. However, after you have been in the room for some time, you no longer notice the incense. Researchers have called this phenomenon habituation. The brain becomes habituated, accustomed to the stimulus, and ceases to register it as important.

It would seem that this is what happens during yoga nidra. While focusing awareness on the sensation of heaviness throughout the body, the nerves fire a volley of impulses to the brain. After some time, however, the brain ignores these impulses, it breaks the connection with the body. The feeling of lightness then arises spontaneously and our awareness floats free of its physical vehicle. Now, rather than physical sensations shaping our consciousness, our consciousness can determine what will be felt by the body.

Stimulation of these homeostatic mechanisms moves us right into the midbrain, and brings greater awareness of the region known as the hypothalamus. This region is the primary regulator of the autonomic (involuntary) nervous system which is intimately bound up with the glands and emotions. Electrical stimulation of certain parts of the hypothalamus gives rise to the emotions of rage, aggression and fear. Most of us find these negative feelings much stronger and harder to control than positive emotions. Nevertheless, in advanced yoga nidra we are asked to submit voluntarily to these threatening emotions, while still maintaining a state of deep relaxation.

This brings into simultaneous operation nerve circuits that, under normal circumstances, never operate at the same time. Thus a new circuit is established incorporating these two apparently irreconcilable states in such a way that relaxation predominates.

In. this way, yoga nidra allows us to experience mental control of our emotions and senses (at least temporarily) and establishes fresh neuronal patterns that we can fall back on to carry this control into our normal waking lives.

The end state of the practice of yoga nidra is ‘psychic sleep’ or sleep in a state of inner awareness. It is a state on the borderline between sleep and wakefulness that allows contact with the subconscious and unconscious mind. Next month we will discuss this state in terms of its psychological and spiritual implications.

(Courtesy Yoga Magazine, January 1979)