The cholinergic synapses.

Acetylcholine (ACh) is a leading regulatory neurotransmitter in the nervous system, which functions both directly and as modulator of other neurotransmitters. It is found in the central and peripheral nervous system, as well as in the autonomic system-both sympathetic and parasympathetic. In the central nervous system (CNS), ACh functions not only as a neurotransmitter, but also as a modulator of cognitive functions, including long-term and short-term memory, limbic activation, and alertness. No process in the mammalian body can commence without its participation.