Acetylcholine neurons in the brain
The source nuclei for the acetylcholine neurons are located in several locations in the brain, and each project to different regions of the brain. Although the number of the neurons is relatively small in comparison to other neurotransmitters, there is a wide distribution. The most significant tracts are the ones that control movement within the extrapyramidal system or are associated with memory and originate from the Meynerts nucleus basalis and project to the cortex.
Damage to these pathways is the probable cause of Alzheimer’s disease.
Outside the brain, acetylcholine is the main neurotransmitter of the parasympathetic nervous system, the system that controls functions such as heart rate, digestion, secretion of saliva and bladder function. Drugs that affect cholinergic activity produce changes in these body functions.