Another common finding in AD is the depletion of cortical cholinergic markers, including a significant reduction of the levels of cortical acetylcholine (ACh) and the activities of choline acetyltransferase (ChAT) and acetylcholine esterase (AChE) enzymes (i.e., the ACh synthesizing and degrading enzymes, respectively) [99,100,101]. Here, CHAT is linked to Alzheimer disease.