Nunn B J, Schnapf J L, Baylor D A
Nature. 1984;309(5965):264-6. doi: 10.1038/309264a0.
Colour vision depends on the wavelength-dependent absorptions of three different photolabile pigments each located in a particular type of retinal cone. The spectral absorption of primate cones has been examined by microspectrophotometry, but this method gives information only at wavelengths where the absorption is relatively strong. Here we have analysed the absorption of two of the cones over a wider range of wavelengths by recording their electrical responses to monochromatic light. The observations were made on the retina of the monkey Macaca fascicularis, an animal thought to have cone pigments like those of man. The measured spectral sensitivities of the red-sensitive ('red') and green-sensitive ('green') cones agreed well with estimates of the cone pigment absorptions derived from colour-matching experiments in humans. At long wavelengths the sensitivity of the red cones was found to decline more rapidly than that of the green. This behaviour, attributable to the cone pigment molecules themselves, explains the paradoxical hue shift, in which a light of very long wavelength is perceived to be identical to a light of shorter wavelength.
色觉取决于三种不同的光不稳定色素对波长的吸收，每种色素位于特定类型的视网膜视锥细胞中。灵长类视锥细胞的光谱吸收已通过显微分光光度法进行了研究，但该方法仅能在吸收相对较强的波长处提供信息。在此，我们通过记录两种视锥细胞对单色光的电反应，分析了它们在更宽波长范围内的吸收情况。观察对象是猕猴（Macaca fascicularis）的视网膜，这种动物被认为具有与人相似的视锥色素。测得的红色敏感（“红”）视锥细胞和绿色敏感（“绿”）视锥细胞的光谱敏感度与从人类颜色匹配实验得出的视锥色素吸收估计值非常吻合。在长波长处，发现红色视锥细胞的敏感度比绿色视锥细胞下降得更快。这种由视锥色素分子本身导致的行为解释了矛盾的色调偏移现象，即波长非常长的光被感知为与波长较短的光相同。
