What is acetylcholine?

I think we have learned that low acetylcholine in the brain is a very important factor. So if your brain acetylcholine goes down, which it does profoundly in the Parkinsonian dementias, you have a tendency to see things that aren’t there. Acetylcholine is a chemical that helps your brain to focus. And I think when it’s not working well, all sorts of things flood into your brain. You have trouble processing them. You have trouble knowing what’s real and what is not.