Recently, we have shown that the AD therapeutic drug donepezil, which increases brain acetylcholine levels, activates Rac1-PAK signaling in the striatum/nucleus accumbens (NAc), a mediator of emotional learning, for enhanced aversive learning in wild-type adult mice via the muscarinic acetylcholine receptor 1 (M1R)-PKC cascade [15]. This evidence concerns the gene RAC1 and Alzheimer disease.