A Tale of Two Retinal Domains: Near-Optimal Sampling of Achromatic Contrasts in Natural Scenes through Asymmetric Photoreceptor Distribution
A Tale of Two Retinal Domains: Near-Optimal Sampling of Achromatic Contrasts in Natural Scenes through Asymmetric Photoreceptor Distribution
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DOI：
10.1016/j.neuron.2013.09.030
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发表时间：
2013-12-04
期刊：
影响因子：
16.2
通讯作者：
Euler, Thomas
中科院分区：
文献类型：
--
作者：
Baden, Tom;Schubert, Timm;Euler, Thomas
为了有效编码，感觉系统需要适应它们所接触的信号的分布。在视觉上，地平线以上和地平线以下的自然景物在彩色和非彩色特征的分布上是不同的。因此，许多物种使用短（S，“蓝色”）和中（M，“绿色”）波长敏感的光感受器类型的不对称视网膜排列来区别地采样天空和地面上的光。在这里，我们表明，在小鼠中，这种感光器的安排提供了接近最佳的采样自然消色差的对比。表达钙生物传感器的视锥光感受器的突触末端中的光驱动钙信号的双光子群体成像显示，S，但不是M视锥，优选黑暗而不是明亮的刺激，与天空中黑暗对比度的优势一致，但不是在地面上。因此，不同的视锥细胞类型不仅形成了“色觉”的基础，而且还代表了不同的（无色的）对比度选择通道。
For efficient coding, sensory systems need to adapt to the distribution of signals to which they are exposed. In vision, natural scenes above and below the horizon differ in the distribution of chromatic and achromatic features. Consequently, many species differentially sample light in the sky and on the ground using an asymmetric retinal arrangement of short- (S, "blue") and medium- (M, "green") wavelength-sensitive photoreceptor types. Here, we show that in mice this photoreceptor arrangement provides for near-optimal sampling of natural achromatic contrasts. Two-photon population imaging of light-driven calcium signals in the synaptic terminals of cone-photoreceptors expressing a calcium biosensor revealed that S, but not M cones, preferred dark over bright stimuli, in agreement with the predominance of dark contrasts in the sky but not on the ground. Therefore, the different cone types do not only form the basis of "color vision," but in addition represent distinct (achromatic) contrast-selective channels.