M1 receptor agonists have been shown to ameliorate Aβ and tau pathology in animal models of Alzheimer's disease (Caccamo et al., 2006) and to be beneficial for patients suffering from Alzheimer's disease and schizophrenia (Dean et al., 2003; Koch et al., 2005) so the development of new allosteric M1 receptor agonists could provide a major breakthrough in the treatment of these cognitive disorders. This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.