APOE and Cognitive impairment: In conclusion, intranasal insulin treatment for 6 weeks can effectively decrease anxiety‐related behaviors and ameliorate cognitive impairments, impaired brain insulin signaling, and neurogenesis, and substantially decrease brain Aβ level and Aβ plaque deposits by shifting APP processing to the nonamyloidogenic pathway and causing a reduction in ApoE protein in young adult APP/PS1 mice.