Kundalini in Gnanam means the following: Kundalini = Kundu + Oli + Nee. In Tamil Kundu means ball. Oli means Light. Nee means You. So Kundalini the word gives the meaning like this "The light in the ball is you". So we the Soul is what represented by Kundalini. Where is the light in the ball? The Soul which is in the center of our head is accessible and expressing itself as the light in our eye ball. This divine light that is expressed in the pupil of our eyes is what called as Kundalini.
Yoga Sastram tells that the Kunadlini is in the end of spinal cord. We donot want that. TiruArutPrakasa Vallalar has clearly told that Pranayam or any other breathing practice will not lead one to to the Supreme Lord. Yoga and Pranayam were not recommeded in this age.
TiruArutPrakasa Vallalar also tells
"Any Spiritual practice will give a vision of small light, many get struck with arrogance and ego and remain in the same state on getting these visions".
Siddhar Tirumoolar also warns about yoga practices in his song in TiruManthiram which is as below:
“Even if one does yoga for 8000 years he cannot see and realize the divinity in the eyes.
Only if you see within yourself with the divine light of eyes you can realize that the SupremeLord is mixed in you” – Saint Tirumoolar
To explain furthur, all the saints of the world have described the Supreme Lord as Light. One who tries to attain the Supreme Light using the air will not succed.
The Soul light is accessible from the Eyes and hence eyes are called as holyfeet of god. (TiruVadi). Capturing the holy feet (divine light in the pupil of the eyes) with the divine consiousness got in the eye via Tiruvadi Deekshai will lead one to self realization and God Realization