The koniocellular layers of the lateral geniculate nucleus are an evolutionary ancient part of the primate visual system. Different koniocellular populations are specialized to process distinct aspects of the visual world. Some cells have on-off receptive fields (left column) that respond to drifting achromatic gratings with an unmodulated spike rate increase that is maximal for moderate spatial frequencies. A different, “blue-on” type of koniocellular receptive field (right column) shows color-selective responses to short-wave cone modulation; responses are maximal at low spatial frequencies. For more information, see the article by Eiber et al. (pages 10384–10398).