| | Trichromatic System vs. Color Opponency System |
 | | An interesting question to ask is why nature would chose to use R-G, B-Y and B-W color opponency system in the brain, instead of the same seemingly simpler RGB (i.e., LMS) system used in the retina. |
| | When two different types of receptors S and ML were evolved in the dichromatic system (most mammals except primates), the brain needed to adapt to process colors in a 2D space, presumably, by adding a new dimension of Blue-Yellow (same as S-ML) to the original B-W,which is the most convenient thing to do. |
| | Therefore the three types of olor-opponent cells in the cortex were evolved as the result of the progressive adaptation of the brain to increased number of receptor types in the retina. |
| fourier.eng.hmc.edu /e180/handouts/color2/node3.html (362 words) |
