The Neural Locus Where Cone Signals Are Combined for Hue Perception

摘要

Thomas young famously proposed that three receptor types account for a??three principal colorsa?? and Helmholtz echoed that three cone types directly account for hue perception saying a??Young's hypothesis is only a special case of the law of specific sense energies.a?? However, Mach and Hering recognized that trichromatic theory could not account for hue perception which is based on opponent processes responsible for four a??primordiala?? hues, blue-yellow and red-green. Trichromacy and opponency have been reconciled by a??zone theoriesa?? first proposed by G. E. M??ller and refined by Judd and Hurvich and Jameson in which the outputs of the cones are neurally recombined early in visual processing. However, more recently an even more central reorganization of L vs. M and S vs. (L+M) ganglion cells has been proposed to account the details of hue perception. We have reexamined this issue by studying people whose visual pathways are greatly simplified because of GRM6 mutations that block all signaling between photoreceptors and ON-bipolar cells. We have found that these patients have S-cone driven bipolar cell responses as assessed by ERG and normal hue opponent vision. This suggests that inhibitory feedback between adjacent cone pedicles is the site where signals responsible for hue perception originate.