Single cell analysis of wavelength discrimination at the lateral geniculate nucleus in the macaque.

Abstract

Previous studies have delineated 4 types of chromatic opponent cells in the macaque lateral geniculate nucleus: red excitatory, green inhibitory (+R-G); green excitatory, red inhibitory (+G-R); yellow excitatory, blue inhibitory, yellow inhibitory (+B-Y). In this study, wavelength discrimination functions were determined for each of these 4 types of opponent cells. These functions were compared with psychophysical hue discrimination data from the same species. The lower bound of the individual cell wavelength discrimination functions agreed with the behavioral data in showing good discrimination at about 490 and 590 nm with relatively inferior discrimination about 540 nm and poor discrimination at the ends of the spectrum. The good wavelength at 490 nm is due to the +Y-B and +B-Y cells; the good discrimination at 590 nm is mainly attributable to the +G-R and the +R-G cells.