Scientific Background: Allosteric activators of the M4 muscarinic acetylcholine receptor represent a novel approach for the treatment of psychotic symptoms associated with schizophrenia and other neuropsychiatric disorders. VU0467154 produced a robust dose-dependent reversal of MK-801-induced hyperlocomotion and deficits in preclinical models of associative learning and memory functions in wild-type mice, but failed to reverse these stimulant-induced deficits in M4 KO mice. VU0467154 also enhanced the acquisition of both contextual and cue-mediated fear conditioning when administered alone in wild-type mice.