Advancing a new approach to stimulate cholinergic functioning in Alzheimer's Disease (AD) is the goal of this proposal. Loss of cholinergic neurons is principally related to cognitive decline in AD and stimulation of these receptors improves cognitive performance. Treatments for AD, first approved over 25 years ago, are designed solely to increase levels of acetylcholine and have had only modest impact on AD symptoms. A number of efforts to develop direct-acting muscarinic cholinergic M1-selective agents were attempted over the last 15 years. While relatively potent, all lacked receptor selectivity with cross-reactivity mostly occurring with M2 and M3 receptors that are responsible for most of the intolerable side effects associated with these compounds. By focusing on a new indirect way to stimulate these receptors, we have developed muscarinic cholinergic M1-positive allosteric modulators (PAM) with a lead compound (VU0467319), a highly selective M1 PAM undergoing development in the Vanderbilt Center for Neuroscience Drug Discovery (VCNDD). In contrast to older muscarinic cholinergic agonists, this compound does not activate the receptor directly but potentiates acetylcholine-induced receptor activation. We propose that cholinergic stimulation of postsynaptic M1 receptors through allosteric mechanisms (either solo treatment or together with standard AD treatment) may improve cognitive symptoms and prevent losses in cognitive abilities in AD over time, without the typical cholinergic side effects that have proved problematic with past muscarinic drug development. The clinical studies in this first-in-human Phase 1 proposal will be unique in combining human tolerability and dose ranging studies with initial "target engagement" strategies combining updated approaches to single ascending dose and multiple ascending dose studies with clinical electrophysiology and cognitive tasks that are analogous to our tested rodent and nonhuman primate studies. We believe that this effort will bring a unique molecular mechanism to development for future clinical and cognitive investigations.