The muscarinic M4R are expressed in the striatum,prefrontalcortex, and nucleus accumbens; these areas are all related to socialbehaviors and cognitive functions.20−22 M4R agonistsand allosteric modulators may be useful for the therapy of Alzheimer’sdisease, schizophrenia, cognitive disorders, or treatment of drugabuse. Here, CHRM4 is linked to schizophrenia.