Protan-like spectral sensitivity of foveal Y ganglion cells of the retina of macaque monkeys.
1. The spectral sensitivity of two varieties of macaque Y ganglion cells with a centre-surround organization, type III (non-colour opponent) and type IV (broad-band colour opponent), was examined with test stimuli of different size, shape and wave-length. 2. The spectral sensitivity of type III cells to large stimuli decreased at the long wave-lengths with decreasing retinal eccentricity; this change was due to a lower sensitivity of green-sensitive than of red-sensitive cone input to the surround of foveal cells, which resulted in stronger surround antagonism at the long than at the short wave-lengths leading to a rudimentary form of colour opponency. 3. The spectral properties of foveal type III cells were intermediate between those of perifoveal type III cells, whose surrounds receive a rather similar input from both cone types, and of the predominantly foveal type IV cells, whose surrounds appeared to lack input from green-sensitive cones. 4. The results indicate that both cell types represent varieties within a continuum of a single macaque Y-cell system which has a reduced long-wave-length sensitivity in the foveal region. The fact that a similar reduction of long-wave-length sensitivity can be observed in (foveal) macaque photopic luminosity functions measured with different techniques by different authors suggest that both types of Y cell have an important role in the processing of luminance information.
D000200:Action Potentials; D000818:Animals; D003116:Color; D005584:Fovea Centralis / Q000166:cytology*; D000882:Haplorhini; D008252:Macaca fascicularis; D008253:Macaca mulatta; D008266:Macula Lutea / Q000166:cytology*; D009474:Neurons / Q000502:physiology*; D010786:Photoreceptor Cells / Q000502:physiology; D013053:Spectrophotometry