Signal Processing in the Inner Retina

哺乳动物的视网膜包含至少40种视网膜神经节细胞(RGC)，每种细胞都能做出最好的反应 视觉场景中不同的、有时是复杂的特征。总而言之，这些不同的研资局反应 为我们提供我们用来在视觉世界中导航的所有信息。每种类型的研资局都会监察 通过收集突触前双极细胞和无长突细胞的输入，在视网膜表面及其感受野上打补丁 其中，分别有12种和50多种。而无长突和无长突的一般模式 有助于RGC光反应的双极细胞连接是已知的，内部令人望而生畏的复杂性 视网膜的突触层阻碍了我们对构成调谐基础的连接的理解 区分RGC类型的属性。具体地说，目前还没有系统的方法来识别所有 向RGC进行突触前输入的细胞，同时研究它们作为 处理单元。该提案使用病毒技术工具箱来跟踪和功能描述 无长突细胞和双极细胞，为杆状优势小鼠和视锥细胞中的特定RGC提供输入 优势地鼠视网膜。在三个具体目标中，我们的目标是：1)使用跨突触狂犬病病毒 表达GFP以将直接的双极细胞和无长突细胞输入映射到 小鼠视网膜;使用一种表达钙指示蛋白GCaMP6的跨突触狂犬病病毒进行研究 小鼠视网膜节细胞与其来自双极细胞和无长突细胞的直接输入之间的功能联系 视网膜;和，3)识别并从功能上描述负责蓝/绿颜色的视网膜内部回路 对手的视线在地松鼠。我们的工作将定义特定视网膜内部的连接和功能 电路处于健康状态，并为了解已知发生的电路变化提供了背景 在光感受器退化之后，无论是由于遗传疾病还是年龄起病。

The mammalian retina contains at least 40 types of retinal ganglion cells (RGCs) each tuned to respond best to different and sometimes complex features in a visual scene. Together, these diverse RGC responses provide us with all of the information that we use to navigate in the visual world. Each type of RGC monitors a patch on the retinal surface, its receptive field, by collecting inputs from presynaptic bipolar and amacrine cells of which there are more than 12 and 50 types, respectively. While the general patterns of amacrine and bipolar cell connectivity that contribute to RGC light responses are known, the daunting complexity of the inner synaptic layer of the retina has impeded our understanding of the connections that underlie the tuning properties that distinguish the RGC types. Specifically, there is currently no systematic way to identify all of the cells that make presynaptic inputs to an RGC and at the same time study their combined function as a processing unit. This proposal uses a toolbox of viral techniques to trace and functionally characterize the amacrine and bipolar cells that provide input to specific RGCs in both the rod dominant mouse and cone dominant ground squirrel retinas. In three specific aims, our goals are to: 1) use a trans-synaptic rabies virus that expresses GFP to map the direct bipolar and amacrine cell inputs to genetically targeted RGCs in the mouse retina; 2) use a trans-synaptic rabies virus that expresses the Ca2+ indicator protein GCaMP6 to study the functional connections between RGCs and their direct inputs from bipolar and amacrine cells in the mouse retina; and, 3) identify and functionally characterize the inner retinal circuits responsible for blue/green color opponent vision in the ground squirrel. Our work will define the wiring and functions of specific inner retinal circuits in health and provide the background for understanding circuit changes that are known to occur following photoreceptor degeneration, whether from genetic or age-onset disease.