Swami Vivekananda was probably the first person to attempt to find parallels between the yogic physiology and the modern physiology. He inferred that the spinal cord is composed in such a manner that its horizontal cross sections would like a figure of 8, placed horizontally, with two parts connected in the middle. Swamiji said that the left is Ida and the right is Pingala and the hollow canal which runs through the centre is the Sushumna. According to Swamiji, the Ida and Pingala are the main channels through which the afferent and efferent currents travel. This is slightly different from modern physiology, according to which afferent and efferent nerves travel on both the sides of the spinal cord. The different plexuses on the spinal cord stand for the different lotuses of chakras.
According to modern physiology there are two nervous systems; the voluntary and the involuntary or autonomic. The autonomic nervous system consists of para-sympathetic and sympathetic nerves. Functions of lungs, heart, stomach, kidneys etc., are governed by these sets of nerves. The function of the lungs i.e. respiration is the only visceral function which can be partially controlled by voluntary action. Swamiji says, “ By systematic practice of Pranayama under a skilled teacher, through the control of the function of lungs, the centre of the autonomic nervous system in the brain may be brought under control, and, through this, all other functions like that of heart and stomach can be brought under control. This, in terms of modern physiology, is the meaning of awakening of Kundalini.
Of course, Swami Vivekananda goes much ahead and states that the purpose of awakening of Kundalini is not merely the control of physical body but, finally, the control of mind. The nerve plexuses on the spinal cord which are equated with the lotuses of the chakras are actually plexuses of both nerves of the autonomic nervous system as well as voluntary nervous system and as one gains control over the autonomic nervous system, he is able to control the whole of his body through these plexuses.
Dr.Mahesh Chandra Panda, M.B.B.S., M.D.