Final answer:
Trichromatic color vision, based on the activity of three types of cones, is enhanced by lateral inhibition leading to opponent-processing, which helps the brain process color as red/green and blue/yellow pairs.
Step-by-step explanation:
Trichromatic color vision relies on three types of cones in the retina, each sensitive to different wavelengths of light—short (S), medium (M), and long (L) wavelengths. The relative activity of these cones allows for the perception of different colors. However, this is not the sole mechanism of color vision, as the opponent-process theory plays a role at a different level of the nervous system. Once visual information passes the retina, some cells are excited by certain wavelengths and inhibited by their opposite, embodying the concept that colors are coded in opponent pairs: black-white, yellow-blue, and green-red. This opponent coding is thought to be enabled partially by lateral inhibition from horizontal cells, which enhances contrast and sharpens edges in our visual perception, helping differentiate red/green and blue/yellow colors more distinctly.
Lateral inhibition facilitates the conversion of the cone's trichromatic responses into the red/green and blue/yellow coding that is characteristic of opponent-process theory. As horizontal cells inhibit the activity of distant photoreceptors, this not only increases visual acuity but also contributes to more complex color processing at the level of the brain. It is a beautiful intricacy of the visual system that combines the initial trichromatic signal with the later opponent-processes, allowing us to experience the rich tapestry of colors in our world.