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佳反应 不同的，有时是复杂的特征。研资局的这些不同回应 为我们提供了在视觉世界中导航的所有信息。每类研资局均会监察 通过收集来自突触前双极细胞和无长突细胞的输入，在视网膜表面（其感受野）上形成斑块 分别有12种和50多种。虽然无长突和 双极细胞连接，有助于RGC光反应是已知的，内部的令人生畏的复杂性， 视网膜的突触层阻碍了我们对调谐背后的连接的理解 区分RGC类型的属性。具体来说，目前还没有系统的方法来确定所有的 这些细胞向RGC进行突触前输入，同时研究它们作为一个神经元的组合功能。 处理单元。该提案使用病毒技术工具箱来追踪和功能性表征 无长突细胞和双极细胞，为视杆细胞和视锥细胞中的特定RGCs提供输入 占优势的地松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，以将直接双极和无长突细胞输入映射到基因靶向的RGC。 小鼠视网膜神经元2）使用表达Ca 2+指示蛋白GCaMP 6的跨突触狂犬病病毒来研究 小鼠视网膜节细胞与其双极细胞和无长突细胞直接输入之间的功能联系 3）识别和功能性地表征负责蓝色/绿色的内部视网膜回路 地松鼠的对手视觉我们的工作将确定特定的视网膜内层的布线和功能， 健康中的回路，并为理解已知发生的回路变化提供背景 光感受器变性后，无论是遗传性或年龄发作性疾病。

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.