Cortical double-opponent cells and human color perception

Human color perception's dependence on the spatial pattern of color is a function of color contrast. At low color contrast, the visual system acts as a spatial integrator of color signals. Therefore, near threshold, the optimum color pattern is a large, uniformly colored region. But the system changes at high color contrast, becoming more sensitive to changes in the spatial context of color especially color boundaries with surrounding regions. We offer a mechanistic explanation of these phenomena in terms of the contrast dependencies of single-opponent and double-opponent neurons in the primary visual cortex, V1.