I am wanting to know which neurochemical processes are directly responsible for crossing the threshold from lucid dream consciousness to awakened consciousness.

I know that in the event of a lucid dream there is an elevated amount of acetylcholine and norepinephrine which contribute to consciousness and alertness. However, if they are partially (or mainly) responsible for it, is there a threshold of elevation of one or both of these neurotransmitters that pushes one into the fully waking state?
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If one is able to understand this better on the neurochemical level, I postulate that one could manage their neurochemical levels through the daytime and lucid state by way of entrainment. By entrainment I mean to isolate the particular thought activities and physiological reactions that correspond to the rise or decline of the pertinent neurotransmitters, and to learn to manage those thought activities and reactions during the day and in subsequent lucid dreams. Of course supplementation is relevant here as well. With successful development in this entrainment, lucid dreams could be significantly prolonged by managing psychic reactions that lead to waking or dream turbulence.

If anyone can give a knowledgeable response to the neurochemical activities responsible for breaking the lucid/waking threshold, I would appreciate it.