CHAT and Alzheimer disease: Reports of substantial neocortical deficits in choline acetyltransferase (ChAT), the enzyme responsible for the synthesis of acetylcholine (ACh), discoveries of reduced choline uptake, ACh release, and loss of cholinergic perikarya from the nucleus basalis of Meynert, along with the emerging roles of ACh in learning and memory, led to the “cholinergic hypothesis of AD” [17].