Abstract

Our model of bipolar cells (BC) of the human central fovea is based on several assumptions; a specified mosaic of red and green cones (no blue cones), and at a steady state adaptation level, the output of BCs is a linear function of image contrast. Center fields of R/G and G/R BCs receive direct inputs from weighted cones, while antagonistic surround fields receive inverted inputs from either L- or C-type horizontal cells. The computer model takes into account appropriate optical aberrations and chromatic filtering due to the eye. Chromatic aberrations are modeled using separate point spread functions for the primary colors. Cone automatic gain control is a function of intensity and wavelength of the adapting light. Spectral responses for R/G and G/R BCs were determined, and once the unique yellow loci were adjusted to 570 nm, and given absorption spectra for the red- and green-sensitive cones, spectral responses were found to be dependent on only the balance between center and surround field responses. Achromatic adaptation produced uniform decreases in responses without shifting the unique yellow loci. Chromatic adaptation clearly demonstrated the Berzold-Brucke effect with the unique yellow loci shifting to shorter wavelengths with adapting wavelengths shorter than 550 nm, and shifting to longer wavelengths with longer adapting wavelengths.

© 1989 Optical Society of America