Most of these atlases are based on a single animal (Cannestra et al., 1997; Saleem and Logothetis, 2006; Van Essen, 2002, 2004); while others are based on small samples of 6–12 animals (Black et al., 2001a; Black et al., 2001b; Greer et al., 2002; Vincent et al., 2007).