Yoga
Nidra and the Brain
Modern
neurophysiologists have been able to demonstrate an obvious relationship
between the body and the brain which was first recognized by the ancient yogis
thousands of years ago. Using stimulating electrodes to probe the brains
surface, neurosurgeons have shown that each part of the body is precisely
mapped out along the surface of the central gyrus or fold of the sensory motor
cortex of the brain. Researchers have named this
neuronal map or hologram of the physical body the motor homunculus (little man) - the symbolic man lying within the
brain matter.
There
is a link between the body and brain through the sensory motor cortex. The
sensory motor cortex is the region of the cerebral cortex where nerve cells are
engaged in planning and directing the actions of muscles and glands that are
under conscious control. All the body parts
through which the awareness passes during rotation of consciousness can be
located there, for example: "Right hand thumb, second finger, third
finger, fourth finger, fifth finger, palm of the hand, back of the hand, wrist,
elbow, shoulder, armpit, right side, right waist, right thigh, kneecap, calf
muscle, ankle, heel, sole, big toe, second toe, third toe, fourth toe, fifth
toe..." This is where we make the connection between the latest
neurosurgery and the meditation technique of yoga nidra.
Yoga
nidra the rotation of consciousness does begin at the right hand thumb as beginning
with the hands affects a huge area of the brain. 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. If you have ever practised this technique, you
will recognize the signposts on the sensory-motor cortex as precisely those
parts of the body through which your awareness passes during rotation of
consciousness in yoga nidra. 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 the
awareness of the body in order to stimulate the brain. The progressive movement
of awareness through the parts of the body not only induces physical relaxation
but also relaxes the sensory-motor cortex of the brain and clears all the nerve
pathways to the brain, both those governing the physical activity and those
concerned with incoming information. At the same time we make a total run
through the brain surface, from inside out. In this way yoga nidra relaxes the
mind by relaxes the body.
Now we can begin to understand why the precise order of rotation
of consciousness throughout the body parts is so important in the practice of
yoga nidra. Once this sequence is established it should not be altered, as it
induces a flow of pranic energy within the neuronal circuit of the motor
homunculus. This flow is accompanied by a subjective experience of relaxation,
release or letting go as spontaneous dissociation of consciousness from the
sensory and motor channels of experience occurs. Familiarity and daily
repetition of this sequence exerts a rapid inturning (inner) effect upon the
normally fragmented and dissipated (worldy pleasures) awareness.
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. 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.