Novales Flamarique Iñigo
Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada V3J 4M5
Department of Biology, University of Victoria, Victoria, British Columbia, Canada V8W 2Y2.
Proc Biol Sci. 2017 Sep 13;284(1862). doi: 10.1098/rspb.2017.0759.
Besides colour and intensity, some invertebrates are able to independently detect the polarization of light. Among vertebrates, such separation of visual modalities has only been hypothesized for some species of anchovies whose cone photoreceptors have unusual ultrastructure that varies with retinal location. Here, I tested this hypothesis by performing physiological experiments of colour and polarization discrimination using the northern anchovy, Optic nerve recordings showed that the ventro-temporal (VT), but not the ventro-nasal (VN), retina was polarization sensitive, and this coincided with the exclusive presence of polarization-sensitive photoreceptors in the VT retina. Spectral (colour) sensitivity recordings from the VN retina indicated the contribution of two spectral cone mechanisms to the optic nerve response, whereas only one contributed to the VT retina. This was supported by the presence of only one visual pigment in the VT retina and two in the VN retina, suggesting that only the VN retina was associated with colour sensitivity. Behavioural tests further demonstrated that anchovies could discriminate colour and the polarization of light using the ventral retina. Thus, in analogy with the visual system of some invertebrates, the northern anchovy has a retina with segregated retinal pathways for colour and polarization vision.
除了颜色和强度外，一些无脊椎动物能够独立检测光的偏振。在脊椎动物中，这种视觉模式的分离仅在一些凤尾鱼物种中被假设过，其视锥光感受器具有随视网膜位置变化的异常超微结构。在这里，我通过使用北凤尾鱼进行颜色和偏振辨别生理实验来检验这一假设。视神经记录显示，腹颞（VT）视网膜对偏振敏感，而腹鼻（VN）视网膜不敏感，这与VT视网膜中仅存在偏振敏感光感受器一致。VN视网膜的光谱（颜色）敏感性记录表明，两种光谱视锥机制对视神经反应有贡献，而对VT视网膜只有一种机制有贡献。这得到了VT视网膜中仅存在一种视觉色素而VN视网膜中有两种视觉色素的支持，表明只有VN视网膜与颜色敏感性相关。行为测试进一步证明，凤尾鱼可以利用腹侧视网膜辨别颜色和光的偏振。因此，与一些无脊椎动物的视觉系统类似，北凤尾鱼的视网膜具有用于颜色和偏振视觉的分离视网膜通路。
