Well, we have three types of color "cones" in our retina, sensitive to different overlapping parts of the frequency spectrum, so the sensory input for any given

Well, we have three types of color "cones" in our retina, sensitive to different overlapping parts of the frequency spectrum, so the sensory input for any given color (mix of frequencies) of light is going to be those three types of cones all firing to varying degrees. http://hyperphysics.phy-astr.gsu.edu/hbase/vision/colcon.html http://hyperphysics.phy-astr.gsu.edu/hbase/vision/colcon.htm... So, since magenta is a mix of red and blue, our "red" and "blue" cones will be most active, but also our "green" cones since its frequency sensitivity also includes red and blue. Some people have 4 types of color cones, not 3, and can therefore differentiate colors (mixes of light frequencies) that normal people can't. But, anyways, our brains neural inputs when seeing various colors does not directly correspond to how we perceive them.