Electroretinogram measurements of cone spectral sensitivity in dichromatic monkeys.

The corneal electroretinogram (ERG) was used to investigate the spectral sensitivities of cones in 12 dichromatic squirrel monkeys (Saimiri sciureus) whose color-vision capacities were established in behavioral tests. Three different varieties of dichromacy were represented among these animals. A flicker-photometric procedure was used in which the ERG response to a rapidly flickering monochromatic test light was compared with the response elicited by a similarly flickering reference light. The spectral-sensitivity functions obtained by the use of this technique are similar to previous estimates of cone spectral sensitivity in dichromatic squirrel monkeys derived from direct microspectrophotometric measurements.