Fig. 3.

Diagram of the retinotopic organization in flattened macaque visual cortex. The diagram is from a right hemisphere, including areas V1, V2,V3, VP, and V3A, based on previous reports (Van Essen and Zeki, 1978; Maunsell and Newsome, 1987;Gattass et al., 1988; Van Essen et al., 1990, 1992; Colby and Duhamel, 1991; Felleman and Van Essen, 1991; Tootell and Taylor, 1995). The internal retinotopy of V3A is based on the descriptions of Van Essen and Zeki (1978), Zeki (1978a,b), Van Essen et al. (1990), and Felleman et al. (1997); the organization described by Gattass et al. (1988) is less consistent. Macaque V4v is not indicated here because its internal retinotopy is known incompletely. A, A representation of retinotopic polar angle. As shown in the pseudocolor logo (A, bottom left), the representation of the upper third of the visual field is coded red, the lower third is codedgreen, and the middle third, centered on the horizontal meridian, is coded blue. Cortical area boundaries corresponding to the representation of the horizontal meridian are indicated by solid white lines, and the vertical meridian is indicated by dotted white lines. Because the horizontal meridian within V3A is not a cortical area boundary, it is indicated only by the blue pseudocolor stripe.B, The representation of visual field eccentricity. As illustrated in the corresponding logo, the foveal representation is coded white, and progressively more peripheral eccentricities are coded red, thenblue, and then green. The pseudocolor scale for eccentricity is scaled logarithmically, in approximate accord with the cortical magnification factor; thus the range of visual field eccentricities is coded by green >blue > red>white.