CX3CR1 and Alzheimer disease: No significant differences in the expression of these genes in 6 month-old B6;Cx3cr1+/+ and B6;Cx3cr1−/− mice (Supplemental Fig. 4) further confirmed that these differences in microglial activation elicited by Cx3cr1 deficiency are indeed driven by AD pathology, and are not observed in the healthy, adult brain.