Abstract

The retina of the primate contains two main classes of ganglion cells: tonic wavelength-opponent cells and the phasic nonopponent cells. When tested with flicker photometry, phasic cell activity goes through minima at intensities close to those set by human observers. Spectral sensitivity so determined approximates the V function. The activity of tonic cells shows a complex pattern and does not go through a minimum at any flicker frequency. Further properties of flicker photometry are applicability of laws of linearity and independence of flicker frequency. We tested ganglion cells of the macaque with such paradigms. Response minima of phasic cells showed both transitivity and additivity. For transitivity, if intensities of wavelengths A and B were adjusted to give minimum response, and also of A and C, then B and C when alternated also provided a minimum. For additivity, alternation of A with 1/2B + 1/2C provided a minimal response. Response minima of phasic cells were also temporal frequency independent. Responses of tonic cells with such paradigms were complex and not to be related to flicker photometric performance. We conclude that phasic ganglion cells are responsible for human performance on this task.

© 1988 Optical Society of America