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RESEARCH PRODUCT

Motion detection in goldfish investigated with the optomotor response is “color blind”

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AbstractThe action spectrum of the optomotor response in goldfish was measured to investigate which of the four cone types involved in color vision contributes to motion detection. In the dark-adapted state, the action spectrum showed a single maximum in the range of 500–520 nm, and resembled the rod spectral sensitivity function. Surprisingly, the action spectrum measured in the light-adapted state also revealed a single maximum only, located in the long wavelength range between 620 and 660 nm. A comparison with spectral sensitivity functions of the four cone types suggests that motion detection is dominated by the L-cone type. Using a two colored, “red-green” cylinder illuminated with two monochromatic lights separately adjustable in intensity, it could be shown that motion vision is “color-blind”: the optomotor response disappeared whenever “isoluminant” red and green stripes were offered. Under this condition, calculations revealed that the L-cones were only slightly modulated by the “red-green” stimulus.