Trichromatic colour opponency in ganglion cells of the rhesus monkey retina

Abstract

Two hundred and eleven colour‐opponent ganglion cells were studied in the central 10 degrees of the retina of the rhesus monkey, to determine the inputs which they were receiving from different cone mechanisms. Spectral‐sensitivity measurements in the presence of neutral and coloured back‐grounds showed that 24% of these cells appeared to receive input from all three cone mechanisms. 2. In 3% of the cells, the red‐sensitive cone mechanism opposed the blue‐ and green‐sensitive ones. In 18% of the cells, the blue‐sensitive cone mechanism opposed the green‐ and red‐sensitive ones. In 3% of the cells, the green‐sensitive cone mechanism opposed the blue‐ and red‐sensitive ones. 3. In 12% of the cells receiving opponent green‐ and red‐sensitive cone inputs, responses from the beta‐band of the red‐sensitive cone mechanism could be detected and distinguished from blue‐sensitive cone input. 4. All cells receiving blue‐sensitive cone input appeared to be trichromatic. The retinal distribution of cells with trichromatic input and that of cells with beta‐band responses seemed to parallel the availability of blue‐sensitive cones in the retinal area being considered. 5. The results indicate that trichromatic interactions in the macaque visual system begin in the retina.