MAPT and Cognitive impairment: Intracerebroventricular streptozotocin (ICV-STZ) injection produces cognitive deficits in rats, as well as cholinergic dysfunction, tau hyperphosphorylation, insulin receptor dysfunction, impaired energy metabolism, and oxidative stress (Hong and Lee, 1997; Prickaerts et al., 1999; Salkovic-Petrisic and Hoyer, 2007; Deng et al., 2009).