Fig. 2.

A hypothesis on the organization of dorsal extrastriate cortex in Old World monkeys, based on studies in New World monkeys. Rosa and Tweedale's (2001) proposal about the organization of third tier cortex in macaque based on the observation that the data on which the accepted subdivision of the macaque cortex is based (shown in panel A) are equally compatible with another interpretation (shown in panel B). (A) Original interpretation of boundaries of visual areas in macaque dorsal extrastriate cortex, based on Gattass et al. (1988) and Colby et al. (1988). Redrawn from Figure 5 of Gattass et al. (1988), with the exception of the organization of area V3A (which was based on Figs. 3, 8, 11, and 13 of the same publication) and area PO [which was based on Colby et al. (1988)]. (B) A re-interpretation of the same data, based on the studies of marmoset monkeys by Rosa and colleagues, and on the studies by Maguire and Baizer (1984) in the macaque. In this model, a lower quadrant representation previously assigned to V3A (corresponding to area PM of Maguire and Baizer) forms the continuation of V3v/VP into the rostral bank of the lunate sulcus and prelunate gyrus. This would result in a VLP/V3 forming a complete representation of the visual field, similar to the New World monkey VLP. The most medial part of the original V3d/V3, combined with area PO, forms the homologue of the New World monkey DM (or V6 of Galletti et al., 1999). Gray area: central 1° of the visual field; other symbols are as in Fig. 1. Here, the thin solid contours indicate areal boundaries which were interpolated based on myeloarchitectural evidence.