Acetylcholine (often abbreviated as ACh) is a critically important neurotransmitter for a wide range of cognitive, physiological, and neurological processes.* The areas in your body that interact with acetylcholine are called, “cholinergic.” Acetylcholine is made by cholinergic neurons and stored in small membrane bound capsules, called vesicles, at the end of the neuron waiting for release into the synapse. The cholinergic system plays an important facilitatory role in some of the cognitive functions such as selective attention, emotional processing, learning and memory .
- In the central nervous system, acetylcholine acts as a neuromodulator for other neurotransmitters while aiding in the long term potentiation of new memories by strengthening synaptic connectivity between newly formed neural circuits 
- Within the peripheral nervous system (PNS), acetylcholine acts on a variety of postsynaptic targets- aiding in the contraction of skeletal muscles, as well as smooth and cardiac muscle regulation 
- In contrast to its role as a neuromodulator in the central nervous system, acetylcholine acts purely as a neurotransmitter in the PNS. Thus, it acts directly in point-to-point transmission from one neuron either to another neuron, the heart, or a glandular cell 
1. Robinson, L., Platt, B., & Riedel, G. (2011). Involvement of the cholinergic system in conditioning and perceptual memory. Behavioural brain research, 221(2), 443-465.
2. Hasselmo, M. E. (2006). The role of acetylcholine in learning and memory. Current opinion in neurobiology, 16(6), 710-715.
3. Changeux, J. (2010). Allosteric receptors: from electric organ to cognition. Annual review of pharmacology and toxicology, 50, 1-38.