Figure 1.

Architecture of the cortical model. In the V1 color layer, there are four color opponent (center+/surround−) responses corresponding to green+/red−, red+/green−, blue+/yellow−, and yellow+/blue−. The V4 color layers are composed of six color responses with both excitatory and inhibitory neurons for each color. For clarity, only the connections for Yellow are shown. V4 Yellow excitatory and inhibitory populations receive input from yellow center, blue surround cells in area V1 (normal arrow), and the V4 yellow inhibitory population inhibits the Magenta and Cyan excitatory groups (arrows with circular heads). The feed-forward connectivity is similar for Red, Green, and Blue. Cyan and Magenta receive feed-forward connections from two V1 layers: Green, Blue and Red, Blue (respectively). The V1 space–time orientation layer contains 28 space–time oriented filters at three spatial resolutions at each spatial location. These filters are converted into Poisson spike trains and project to MT and V4 Orientation neurons. See text for connectivity details.