An overview of the mouse hippocampus versus cortex-specific differential effect of Chrm1 deletion on mitochondrial phenotypes, its implications in understanding the relationship between hippocampal versus cortical loss of CHRM1 in AD patients and disease outcome (survival), and the mechanistic interpretation of some behavioral phenotypes observed in Chrm1−/− mice have been diagrammatically summarized in Figure 6. This evidence concerns the gene CHRM1 and Alzheimer disease.