Simulated bipolar cells in fovea of human retina. VI. Wavelength discrimination.

A computer model of simulated bipolar cells (BC) in the human retina is used to study wavelength discrimination (lambda delta). lambda delta curves are obtained for the two C-types of BCs in the central fovea and the three C-type BCs of the parafovea under various conditions. For the parafovea algebraic addition of the three C-type BCs with proper weighting of the blue-center BC, such that the unique orange locus = 600 nm, gives a combined channel whose lambda delta curve agrees remarkably well with those found in the literature based on human and primate psychophysics. Other studies include effects of chromatic adaptation and dispersion on lambda delta. From this and earlier studies it can be concluded that the center/surround organization of the BCs optimize resolution in the presence of natural occurring dispersion; in addition a specific BC receptive field organization could be picked as being optimal.