High levels of acetylcholine are linked with increased REM sleep. That may be the reason that the most potent lucid dreaming supplements either increase acetylcholine levels in the brain or stimulate the acetylchonic receptors.
But there are ways to increase the levels of this substance in the brain without the use of substances.
The german physican Dr. Joseph Zehentbauer investigated other ways of raising the brain levels of acetylcholine.
He lists following methods:
Producing vivid internal images, he claims, will increase brain levels of Noradrenaline, Dopamine and Acetylcholine.
Active Imagining was invented by C.G. Jung as a form of therapy.
Zehentbauer uses this term as a generic name for every method which stimulates ones phantasy.
Where you guide your awareness in your body influences your brain. If you guide your attention to your brain your acetylcholine and noradrenaline levels increase whereas attention to your body raises your endorphine levels.
Just get into the flow of new ideas. The delicate state your brain is in when creating new ideas rises the acetylcholine levels as well.
Of course: Acetylcholine is the neurotransmitter of memory. According to Dr. Zehentbauer the claim is true that intense learing makes your memory transmitter levels rise.
Some of this methods like active imagining suit better in the evening whereas studying or brainstorming are ideal for doing during a WBTB.
So there is an interesting field for new experiments.
Slow-wave sleep, acetylcholine, and memory consolidation
Basal forebrain acetylcholine release during REM sleep is significantly greater than during waking