Full kundalini awakening results when we indulged in jnana yoga (path of absolute wisdom). Path of jnana yoga means indulging in contemplation (chintan) most of time to reach hidden underlying truths of cosmic life contained in sacred texts of different religions of world.
Literally one can never reach hidden underlying truths, prime reason why contents of Bhagavad Gita can never be understood merely by reading it. Contemplation (indulgence in chintan) is the only path to cut across darkness of ignorance.
In present times the Kali Yuga, indulgence in bhakti yoga and karma yoga along does not suffice. Ignorance in matters spiritual can be cut only by contemplation (chintan) on sacred texts contained in scriptures of different religions of world.
The biggest problem facing seekers in present times is indulgence in contemplation. None wants to do that. In 1985 I took a whirlwind tour of world spanning 40 days just to assess the level of spirituality practiced in entire world. I returned empty-handed. Whomever I met none could detail correctly meaning of spirituality, what to talk of indulging in contemplation!
Almost all preferred taking easier path, path of religion (rituals) and not of spirituality that demands indulgence in contemplation. If we mastered art of contemplation we can dive deep within to understand the hidden underlying meaning of sacred texts. Doing so, we awakened our kundalini in stages. This resulted in intermittent activation of dormant lying portions of brain.
For full awakening of kundalini, simultaneous practice of absolute celibacy is also necessitated. When our kundalini awakened fully, it energizes brain to full capacity 100%. One immediately experiences full spiritual awakening, becoming an enlightened one in the bargain.
Full kundalini awakening, full spiritual awakening means our brain opening 100%, one finally becoming knower of all, reaching state of enlightenment forever. Spiritual journey and kundalini awakening are interrelated, proportional.