Cytoarchitectonic area 19 (peristriate cortex, presumed homolog of V3 of primates—Payne, 1993; Rosa and Manger, 2005) and cytoarchitectonic area 21a (presumed homolog of V4 of primates—Payne, 1993), like PTV, constitute distinct parts of the pattern/form information processing cortical stream (area 19: Sprague et al., 1977; Khayat et al., 2000; reviews Orban, 1984; Dreher, 1986; Dreher et al., 1996; area 21a: Dreher, 1986; Mizobe et al., 1988; Wimborne and Henry, 1992; Dreher et al., 1993; Lomber et al., 2001; Villeneuve et al., 2009). Both areas 19 and 21a have substantial direct interconnections with the primary visual and PTV cortices, and are likely therefore to play important roles in shaping the exchange of information between PTV and V1 (Figure 1B, for reviews, see Rosenquist, 1985; Dreher, 1986; Dreher et al., 1996; Batardiere et al., 1998). Indeed, reversible inactivation of entire area 21a and part of area 19, results in substantial changes in the magnitude of responses and many RF properties of large subsets of neurons in the visuotopically corresponding part of V1 (Wang et al., 2000).