Abstract
Abstract: :
Purpose: The stage in the visual system where color constancy is induced has been an issue of debate for many years. Edwin Lands retinex model described that both the retina and the cortex are involved. Recently, it was proposed that the horizontal cell to cone feedback system is responsible for an essential coding step of color constancy (Kamermans et al. , 1998), implying that retinal ganglion cells already transmit color constant information. The aim of this study is to test this hypothesis by studying color constancy and color induction at ganglion cell level. Methods: Ganglion cell activity was recorded extracellularly in the isolated goldfish retina. The receptive field structure and the spectral sensitivity were determined. The receptive field was stimulated with red, green and blue flashes of light with a chromatic surround to induce color induction or a chromatic background to induce color constancy. Results: In the color induction experiments, the ratios of the responses to red, green, and blue flashes shifted towards the complementary color of the surround. In the color constancy experiments the ratios of activity were independent of the background illumination. Conclusions: Color constancy and color induction are for a major part induced in the retina.
Keywords: ganglion cells • color appearance/constancy • retinal connections, networks, circuitry