Psychophysiology (Study of Body and Mind)
The branch of biology dealing with the functions and vital processes of living organisms or their parts and organs is known as physiology. The Bhagavad-gita informs us about the gross and subtle bodies of the living organism. The gross body is visible to us and is made of earth, water, fire, air and ether. The subtle body comprises of the mind, intelligence and false-ego and we can experience their presence.
Bhagavad-gita 3.42 mentions, “The working senses are superior to dull matter; mind is higher than the senses; intelligence is still higher than the mind; and he [the soul] is even higher than the intelligence.”
Modern science has yet to give a proper definition of the mind, intelligence and ego, their nature and function. The Bhagavad-gita explains these in minute detail. For a detailed study on this subject, the reader is requested to refer to the Bhagavad-gita As It Is by A.C. Bhaktivedanta Swami Prabhupada