Table 1.
Binocular overlap and functional organization of orientation processing in the major animal models of vision
| Common name | Species | Order | Eye position | Orientation mapa | Binocular overlapb | Orbital convergenceb |
|---|---|---|---|---|---|---|
| Mammals | ||||||
| Human | Homo sapiens | Primate | Frontal | ✓ | 140° | 79.3° |
| Macaque | Macaca mulatta | Primate | Frontal | ✓ | 140° | 73.9° |
| Owl monkey | Aotus trivirgatus | Primate | Frontal | ✓ | 138° | 67.5° |
| Marmoset | Callithrix jacchus | Primate | Frontal | ✓ | 90–100° | 55° |
| Cat | Felis silvestris | Carniovora | Frontal | ✓ | 98–120° | 66.3° |
| Ferret | Mustela putorius | Carniovora | Lateral | ✓ | 80° | 35.3° |
| Tree shrew | Tupaia glis | Scandentia | Lateral | ✓ | 60° | 32° |
| Squirrel | Sciurus carolinensis | Rodentia | Lateral | ✗ | 60° | 22.1° |
| Rat | Rattus rattus | Rodentia | Lateral | ✗ | 40–60° | 32° |
| Mouse | Mus musculus | Rodentia | Lateral | ✗ | 35–40° | 38.3° |
| Rabbit | Lepus sp. | Lagomorpha | Lateral | ✗ | 24–32° | 20° |
| Birds | ||||||
| Barn owl | Tyto alba | Strigiformes | Frontal | ✓ | 44° | 81.44° |
| Pigeon | Columba livia | Columbiformes | Lateral | ✗ | 22° | 80.44° |
A general relationship exists between the presence of orientation maps and the extent to which an animal's eyes are frontally placed. Disregarding absolute numbers, animals that do not possess orientation maps in primary visual areas have approximately one-half the binocular overlap of animals that do. In birds, the maximal overlap is 40–50° (kestrels) versus 140–150° (primates) in mammals.
aOrientation maps: human (Yacoub et al., 2008); macaque (Blasdel and Salama, 1986); owl monkey (Xu et al., 2004); marmoset (McLoughlin and Schiessl, 2006); cat (Bonhoeffer and Grinvald, 1991); ferret (Weliky and Katz, 1994); tree shrew (Bosking et al., 1997); squirrel (Van Hooser et al., 2005); rat (Ohki et al., 2005); mouse, electrophysiology (Dräger, 1975); rabbit, electrophysiology (Bousfield, 1977; Murphy and Berman, 1979); barn owl (Liu and Pettigrew, 2003).
bBinocular overlap and orbit convergence. The references for these values were mainly derived from the study by Heesy (2004), his Table 1. Human (Vakkur and Bishop, 1963); macaque (Vakkur and Bishop, 1963; Ross, 1995); owl monkey (Allman and McGuinness, 1988); marmoset (Cartmill, 1971; Fritsches and Rosa, 1996); cat (Hughes, 1976; Arrese et al., 1999; Finarelli and Goswami, 2009); ferret (Garipis and Hoffmann, 2003); tree shrew (Hughes, 1977); squirrel (Kaas et al., 1972; Van Hooser et al., 2005); rat (Arrese et al., 1999); mouse (Dräger, 1978; Arrese et al., 1999); rabbit (Wall, 1942; Hughes and Vaney, 1982); barn owl (Iwaniuk et al., 2008); pigeon (Iwaniuk et al., 2008).