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On threshold mechanisms for achromatic and chromatic vision

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Author: Bouman, M.A. · Walraven, P.L.
Institution: Instituut voor Zintuigfysiologie TNO
Source:Acta Psychologica, 3, 36, 178 - 189
Identifier: 4370
Keywords: Vision · article · color vision · differential threshold · human · photoreceptor · physiology · psychophysics · retina · vision · Color Perception · Differential Threshold · Human · Photoreceptors · Psychophysics · Retina · Vision


On the basis of measurements of the achromatic zone for red light in the fovea and for green light in the periphery, a discussion is given on the possible difference in threshold mechanisms for the achromatic (scotopic) and chromatic (photopic) retinal systems. A specific suggestion for this distinction is given that not directly refers to the usual rod-cone concept but is based on the occurrence of multiple coincidence of quantum absorptions by multiple hits per receptor no matter rod or cone as photopic signals, versus multiple coincidences by single hits per receptor in a distinct ommatidium type group of receptors as scotopic signals.