‘Patanjali Yoga sutras’ is the oldest book on Yoga. It is generally believed to have been written more than 2500 years ago though nobody is sure of the dates.

All yoga science originates from it. Patanjali mentions all the attributes of Yoga including yama, niyama, posture, pranayam etc. but somehow there is no mention of Kundalini !

Kundalini yoga is an important part of Tantric yoga system where yogis believe that through the extremely small central canal of spinal cord, sexual chemicals can be raised to reach the brain where they enhance the communication of neural pathways so that all the parts of brain work in unison and one can attain Samadhi. This is similar to what takes place in the brain during the LSD episode, though the user has no control over his experience.

Yogis also believe that the sexual energy is coiled at the base of the spine hence the name Kundalini (coiled energy, snake etc.). They believe it can be raised in the central canal – also called Shushumna nadi, by will.

Physical Basis of Central Canal

Most of the vertebrates have a central canal. In humans it is a small opening of about 1-5 mm diameter in the center of the spinal cord and is elliptical in shape.

There are conflicting reports about its function and its length. fMRI studies (very few of them) have shown that it stretches all the way from the base of the spine to the back of the brain and remains open till about 20-25 years’ of age. Some studies have shown that in late life it closes.

The function of this central canal is also not clear and some researchers say that it is filled with cerebrospinal fluid (CSF) but what exactly is the reason is not yet clear.

Kundalini Yoga

But almost all practitioners of Tantric and Kundalini Yoga swear by central canal (called Shushumna nadi). Yet physically it is not clear how the sexual chemicals are accumulated at the base of the spine and go through the central canal, though yogis claim that one can do so by willing it. Shri. Ramakrishna the great saint of Bengal was a great proponent of Kundalini Yoga and used to vividly describe its ascent, starting from the base of spine but would go into Samadhi when it reached vishudhi chakra or thyroid gland near the throat.

The proponents of Kundalini Yoga also claim that it takes about 12 years’ of complete celibacy to accumulate enough sexual chemicals for their ultimate rise in central canal.

Sexual chemicals such as Dopamine, Norepinephrine, Testosterone, Oxytocin, Serotonin etc. are very important for the functioning of the brain. They help in memory enhancement and hence in the process of concentration and meditation. They are produced in the brain and other parts of the body including the endocrine glands. They fuel the sexual and creative drive. History of mankind is replete with creative people who also had a powerful sexual drive.

A process by which these chemicals could be deposited in the brain without their dilution by the blood stream, the yogis felt, would be very useful. That could be their reason for the importance of the central canal.

However, what is the mechanism by which these chemicals are lifted in the central canal from the base of the spine to the head against gravity forces? (if it does indeed happen!). In nature such passive lifting of chemicals and water takes place in the trees where the water evaporating from the leaves of the plants provides the force to lift the water chain all the way from roots to the top of the tree. Such mechanism for the central canal has not been discovered yet.

The most plausible explanation appears to be that the signal from the sexual organs is transferred to the brain via the vagus nerve.

Vagus nerve is the longest nerve in the human body and is often called the communication highway. It transmits information from various autonomous organs like heart, intestines, kidney, etc. to the brain and vice versa.

It touches all the internal organs including the endocrine glands. It does not transmit the chemicals but only the electrical signals to the brain. It is quite possible that just like the 3D printing, the vagus nerve transmits the template of chemicals electronically to the brain where it releases these chemicals (similar to 3D printing). Energy wise this is much simpler and faster than getting the chemicals delivered directly to the brain via the central canal.

This strategy is also borne out by experiments. Quite a number of times patients whose spinal cord was damaged were able to reach orgasm. Scientists were surprised by this, since all the information from sexual organs is passed to the brain through the spinal cord. It was discovered that vagus nerve was responsible in passing this information to the brain.

That is probably the reason why Patanjali says that Sanyam on nabhi (navel) and esophageal tube gives different powers to the Yogi. Both these places are richly and nicely connected by vagus nerve !

Thus I feel that Patanjali had an extensive knowledge of the human body and felt that vagus nerve plays a central role in passing the information about sexual chemicals to the brain. That is probably the reason why he never mentioned anything about Kundalini in his yoga sutras but focused on making brain powerful through Sanyam, so that it could very effectively process information from different parts of the body.

References

1. B. K. S. Iyengar, Light on Yoga Sutras of Patanjali, Harper Collins Publishers, India. 1993.
2. Swami Sivananda, Kundalini Yoga, Divine Life Society. India, 1994.
3. Erfamul Sakar, et. al, (Dec. 12, 2016), “The human central canal of the Spinal cord: A comprehensive review of its anatomy, embryology, molecular development, variants and pathology”, Cureus 8(12), e 927. DOI 10.7759/cureus.927.
4. Kyung Hyum Kim, et. al., (2013), “Changes in Spinal canal diameter and vertebral body height with age”, Yousei Med J, 54 (6) : 1498-1054.
5. Ida N. Drosdal, et. al., (2013), “Effect of the central canal in the spinal cord on the fluid movement within the cord”, The Neuroradiology Journal, 26 : 585-590.
6. M. C. Petil-Lacour, et. al., (2000), “Visibility of the central canal on MRI”, Neuroradiology, 42, pg. 756-761.
7. Dan Hurley, “How sex affects intelligence, and vice versa”, The Atlantic, 13 Jan. 2014.
8. Ted L. Tewfik, et. al. (2015), “Vagus Nerve anatomy”, http://emedicine.medscape.com/article/1875813-overview
9. B. R. Komisaruk, et. al., (2004), “Brain activation during vaginocervical self-stimulation and orgasm in women with complete spinal cord injury: fMRI evidence of mediation by the vagus nerves”, Brain Research 1024, pg. 77-88.