Neurones with strong inhibitory S-cone inputs in the macaque lateral geniculate nucleus

Neurons with strong inhibitory short-wavelength sensitive cone (S-cone) inputs have been identified in the macaque geniculate using a tritanopic confusion line test, i.e. by stimulation with equiluminous stimuli which leave excitations of long- and middle-wavelength sensitive cones (L- and M-cones) constant while differentially exciting S-cones. Mathematical simulation of the responses of these cells, using known spectral sensitivities of the cone receptors, demonstrates that they receive excitation from M-cones, inhibition from S-cones, and little or no inhibition from L-cones. Excitatory and inhibitory pools are largely spatially coextensive.