Abstract
The encoding of visual object perception is achieved at early visual processing stages by distinct circuitry for object surface (e.g. color) and object shape (e.g. contour) features. In Macaque monkeys, within primary visual cortex (V1), blobs and interblobs are associated with color and form processing, respectively; in the second visual area (V2), color and form are associated with distinct functional stripes. However, little is known about the functional circuitry between such structures. We have examined functional interactions within and between color and form pathways in V1 and V2 by conducting cross correlation studies of pairs of V1–V2 neurons. We find evidence for two distinct functional networks between V1 and V2. The network for color tends to be color-matched and is characterized by a broad divergent network capable of linking distant locations in the visual field. We find V1–V2 form networks are of two types: a more tightly synchronized, orientation-preserving network and a less synchronized orientation-diverse network. In contrast to the divergence of color networks, the form network is more spatially focussed, exhibiting only local spatial interactions. Our examination of interactions between surface and form suggests the presence of a border-to-surface direction of information flow. We suggest that such diversity of V1–V2 interactions underlies the spatial and functional integration required for computation of higher order surface and form perception.