The cortical cholinergic innervation is derived from cholinergic projection neurons within selected nuclei within the BF, mainly from the nucleus basalis of Meynert (nBM).31 Since a deficit of endogenous ACh could be relate to the cholinergic denervation or loss from the cholinergic system within the BF, fluorescence immunohistochemistry for ChAT, a cholinergic cell marker; and tauopathy (human mutant tau P301L and phosphorylated tau at Thr181), which is associated with neurodegeneration in AD patients and rodent models,39,40 were examined in BF of 3xTgAD and WT mice. Here, CHAT is linked to Alzheimer disease.