“Wisdom (knowledge) is a tree of life to them that lay hold of her,” the mystery teachers said, and by “tree” they meant the human cerebrospinal system. When it is stimulated by a new and more potent form of Life Energy, called prana, the nervous system becomes the Tree of Life.
Then an extraordinary change occurs, marking the beginning of a highly accelerated evolutionary activity in the body, known to adepts as the awakening of the Serpent Power, or Kundalini.
The main participants in this almost unbelievable inner drama, designed to fashion the whole system to a new awareness, beyond the normal limits of consciousness, are the brain, the sexual organs and all the nerves of the body.
It is a process of rebirth in which the whole system develops a new biological function and a supersensory channel of perception, designated in the ancient texts as the Third Eye or Sixth Sense.” 
- http://www.kundaliniresearch.org/gnostic.html [↩]