The level of glutamate signaling protein in the prefrontal cortex in AD and its relationship with the APOE4 genotype may determine the expression levels of glutamate receptors and the amount of synaptic protein in the prefrontal cortex [52], thus indicating that targeting effort of glutamate receptors in AD may be dependent on the APOE4 genotype (Table 1). This evidence concerns the gene APOE and Alzheimer disease.