AIF1 and Mental deterioration: We observed that the number of Iba1-positive (i.e., microglial) cells was increased in STZ-induced mice and in db/db mouse brain (Fig. 7A and B) raising the possibility that the activity of microglia may be related to cognitive decline in diabetic mice and that these changes were normalized in STZ-induced diabetic mice carrying the p66Shc (−/−) genotype.