School of Life Sciences, University of Sussex, Brighton, UK.
Institute of Ophthalmic Research, University of Tübingen, Tübingen, Germany.
Nat Commun. 2023 Aug 31;14(1):5308. doi: 10.1038/s41467-023-41032-z.
In vertebrate vision, early retinal circuits divide incoming visual information into functionally opposite elementary signals: On and Off, transient and sustained, chromatic and achromatic. Together these signals can yield an efficient representation of the scene for transmission to the brain via the optic nerve. However, this long-standing interpretation of retinal function is based on mammals, and it is unclear whether this functional arrangement is common to all vertebrates. Here we show that male poultry chicks use a fundamentally different strategy to communicate information from the eye to the brain. Rather than using functionally opposite pairs of retinal output channels, chicks encode the polarity, timing, and spectral composition of visual stimuli in a highly correlated manner: fast achromatic information is encoded by Off-circuits, and slow chromatic information overwhelmingly by On-circuits. Moreover, most retinal output channels combine On- and Off-circuits to simultaneously encode, or multiplex, both achromatic and chromatic information. Our results from birds conform to evidence from fish, amphibians, and reptiles which retain the full ancestral complement of four spectral types of cone photoreceptors.
在脊椎动物的视觉中，早期的视网膜回路将传入的视觉信息分为功能相反的基本信号：ON 和 OFF、瞬态和持续、彩色和非彩色。这些信号一起可以为通过视神经传输到大脑的场景提供有效的表示。然而，这种对视网膜功能的长期解释是基于哺乳动物的，目前还不清楚这种功能排列是否普遍存在于所有脊椎动物中。在这里，我们展示了雄性家禽小鸡使用一种从根本上不同的策略来将眼睛的信息传递到大脑。小鸡不是使用功能相反的一对视网膜输出通道，而是以高度相关的方式对视觉刺激的极性、时间和光谱组成进行编码：快速非彩色信息由 OFF 回路编码，而慢速彩色信息则主要由 ON 回路编码。此外，大多数视网膜输出通道将 ON 和 OFF 回路结合起来，同时编码或多路复用，同时包含非彩色和彩色信息。我们从鸟类获得的结果与鱼类、两栖动物和爬行动物的证据一致，这些动物保留了四种光谱类型的视锥感受器的完整祖先成分。
