“The subtle body is a field of energy whose form is more fluid than the physical body. Energy (prana) flows through subtle channels called nadis. These channels permeate the entire subtle body. The mind can be understood to be the sum total of all of the nadis, as the mind can not function without the nadis and the nadis can not exist without the mind. The mind is the field and the nadis are the channels through which pranic energy flows. Classical yogic texts state that there are 72,000 nadis. The nadis energize the subtle body in a manner similar to the way the nervous system energizes the physical body. In fact, the nadis are the astral template of the nerves themselves. The mind is the astral template of the brain. Whereas the brain is the initiator of energy carried by the nerves, our mind (manas) and higher faculties such as the buddhi (intellect) are the initiators of the energy carried by the nadis in the subtle body.
The nadis are the subtle channels that carry prana through the field of the mind. When the nadis are functioning properly, the mind is clear and vibrant. A person is psychologically healthy…The mind is the initiator of pranic movement. However, altered flow through the nadis will also affect the mind. Hence, diseases of the mind, emotions and intellect may originate either in the mind or the nadis.”
Excerpt from “Principles of Ayurvedic Medicine,” by Dr. Marc Halpern, Founder of the California College of Ayurveda