Chromatic induction: responses of neurophysiological double opponent units?

Equations have been derived that improve the quantification of sensory equidistant colour and lightness differences. This has been achieved by a physiological approach involving non-linear responses of cone mechanisms and two subsequent stages of linear opponent transformation to describe the Munsell System (Seim and Valberg, 1980). Using the formulation for the first opponent stage, colours induced into an achromatic center field by a chromatic surround varying in purity, are shown to follow the same power function of the opponent coordinates for all hues. By analogy, a physiological model for colour coding and colour induction is offered. Double opponent neurones with spatially antagonistic, spectrally opponent and symmetric receptive fields constitute the units of the model. Colour induction is related to lateral excitation and colour differences to response differences of these units.