“…In primary visual cortex (V1), the architecture of Old World monkeys and great apes, including humans, is qualitatively similar, although there are numerous quantitative differences among these species (Horton and Hedley-Whyte, 1984; Preuss et al, 1999; Preuss and Coleman, 2002; DeFelipe et al, 2006). One common characteristic of the visual system across these species is the distribution of the three cone photoreceptors (L-, M-, and S-cones) that feed into the different classes of ganglion cells giving rise to the correspondingly elaborate retino-geniculo-cortical pathway (Leventhal et al, 1981; Livingstone and Hubel, 1988; Kaas and Huerta, 1988; Conley and Fitzpatrick, 1989; Casagrande and Norton, 1991; Casagrande, 1994; Hendry and Yoshioka, 1994).…”