Light Propagation through the Retina: Vertebrate Retinal Optics

尽管脊椎动物的视网膜是倒置的，但它是如何正常工作的，这是一个古老的谜：光必须通过视网膜的所有层（光散射）才能被感光细胞检测到。最近，我们已经证明，束状神经胶质细胞作为光引导纤维，绕过视网膜内层。然而，这种光导必须在外核层结束，在那里，<s:1>勒细胞过程分裂成薄的细胞质舌。我们的合作伙伴提出了一个假设，即光感受器细胞核的放射状排列作为“透镜链”，连接了<s:1> ller细胞干细胞过程和光感受器内部片段之间的距离。为了验证这一假设并阐明通过整个视网膜的复杂光路，我们将进行(i)对后续导光元件之间的数值关系进行定量分析，（ii）对它们之间的“过渡区”进行结构分析，以及（iii）对通过视网膜的光传递进行直接可视化。对于后一种目的，激光将通过一根薄纤维照射到视网膜的内表面。激光束的光路将被监测，以及由它在视网膜结构内引起的荧光，用荧光活性染料标记。在与剑桥的合作伙伴的合作下，将对光通过视网膜的传输进行数学建模。

It is an old enigma how the vertebrate retina can function properly despite being inverted: light must pass all (light scattering) retinal layers before it can be detected by the photoreceptor cells. Recently we have shown that Müller radial glial cells act as light guiding fibers, bypassing the inner retinal layers. However, this light guidance must end at the outer nuclear layer where the Müller cell processes split into thin cytoplasmic tongues. Our collaborating partner has forwarded the hypothesis that the radial rows of photoreceptor cell nuclei serve as ‘chains of lenses’ bridging the distance between the Müller cell stem processes and the photoreceptor inner segments. To test this hypothesis and to elucidate the complex light path through the entire retina, we will perform (i) a quantitative analysis of the numerical relation between the subsequent light-guiding elements, (ii) a structural analysis of the ‘transition zone(s)’ between them, and (iii) a direct visualization of light transfer through the retina. For the latter purpose, laser light will be applied by a thin fiber to the inner surface of the retina. The light path of the laser beam will be monitored, as well as the fluorescence induced by it within the structures of the retina, labeled by fluorescent vital dyes. In collaboration with the partner in Cambridge, mathematical modeling of light transport through the retina will be performed.