Thus, the group of Hoyer and colleagues have suggested that rats treated with intra-cerebroventricular (i.c.v.)STZ represent a sporadic AD animal model characterized by a specific insulin-resistant brain state (Nitsch and Hoyer, 1991; Duelli et al., 1994; Lannert and Hoyer, 1998; Salkovic-Petrisic and Hoyer, 2007). This evidence concerns the gene INS and Alzheimer disease.