INSR and Insulin resistance: These results could imply a redressing of an insulin starvation state, as studies have shown that the aged brain has reduced IR expression, diminished insulin transport into the CNS, and may even experience insulin resistance (Biessels et al., 2002; Cholerton et al., 2011; Frazier, Ghoweri, Anderson, et al., 2019; Rhea & Banks, 2019).