Retinal ganglion cells and parvocellular LGN cells exhibit spectral opponency. This means they are activated by certain wavelengths and inhibited by others.

• Each of these ganglion cells processes information from two or three types of cones.
• Some of these cones are excitatory and some are inhibitory.
• Ganglion cells respond based on the differences between excitatory and inhibitory input.
• Proportion of spectrally opponent cells in the LGN correlates to degree of color vision.