Memory and Acetylcholine

Acetylcholine ( ACh ) was discovered in the 1920s, making Acetylcholine ( ACh ) the first known neurotransmitter. This neurotransmitter can be found in the brain, neuromuscular junctions, spinal cord, and in both the postganglionic terminal buttons of the parasympathetic division of the autonomic nervous system and the ganglia of the autonomic nervous system.
Acetylcholine ( ACh ) is synthesized from acetyl-CoA and Choline. Chemical reactions in brain for the production of Acetylcholine ( ACh ):

ACh receptor sites can be ionotropic ( nicotinic receptor ) or metabotropic ( muscarinic receptor), this make it possible for acetylcholine to produce either an IPSP or an EPSP response.
Only recently it was discovered that the nucleus basalis, particularly in the nucleus basalis of Meynert, is a source of acetylcholine ( ACh ). It was subsequently shown that projections from the nucleus basalis provide the primary source of neocortical acetylcholine ( Mesulam and Van Hoesen, 1976; Lehmann, Nagy, Atmadja, & Fibiger, 1980). There are also cholinergic projections from the adjacent medial septum and diagonal band of Broca to hippocampus ( Squire, 1987 ). All these cholinergic projections together making up a wide source of acetylcholine ( ACh ) in the brain.
Acetylcholine ( ACh ) role in learning and memory is on clear but Deutsch in 1970 believed that because most the acetylcholine ( ACh ) in the neocortex originates in the basal forebrain, that cholinergic synapses themselves were the sites for memory storage. However Squire believes these cholinergic pathways are better suited for some type of modulator role but in what way is yet unclear. The ascending, widely projecting cholinergic pathways seem better suited as a modulator system than as an information-containing, information-storing system (Squire, 1987).