Light responses and microcircuitry of two novel amacrine cell types in the retina

 描述(申请人提供)：尽管几十年来对视网膜中多种细胞类型的结构和功能进行了研究，但视网膜无长突细胞的编码特性仍然很大程度上是未知的。我的研究的总体目标是通过表征视网膜的内在特性，为我们目前对视网膜视觉处理的理解做出贡献 和两个新发现的视网膜无长突细胞亚型的连接性。目的：研究CRH-1视网膜无长突细胞的生理特性和突触微电路。我将是第一个(A)表征基因标记的CRH-1无长突细胞对各种视觉刺激的光反应的人。然后，我将(B)通过鉴定突触后视网膜神经节细胞将CRH-1放入功能电路的上下文中。这些测量将使我能够确定CRH-1细胞是否可以介导视网膜内的前馈抑制。探讨nNOS-2无长突细胞间缝隙连接偶联的动力学及其在视觉加工中的作用。在对另一种基因标记的无长突细胞nNOS-2进行的初步实验中，我发现这些细胞形成了一个广泛的耦合网络。我将研究(A)nNOS-2偶联是否受平均亮度的调节，以及调制信号通路是否涉及多巴胺或一氧化氮。我还将(B)通过测量树突状细胞的形态和同一细胞中的感受野来确定nNOS-2偶联如何影响视觉反应特性。

 DESCRIPTION (provided by applicant): Despite decades of research characterizing the structure and function of numerous cell types in the retina, the encoding properties of retinal amacrine cells remain largely unknown. The overall goal of my research is to contribute to our current understanding of visual processing in the retina by characterizing the intrinsic properties and connectivity of two newly identified retinal amacrine cell subtypes. To determine the physiological properties and synaptic microcircuitry of the CRH-1 retinal amacrine cell. I will be the first to (A) characterize the light responses of genetically labeled CRH-1 amacrine cells to a variety of visual stimuli. I will then (B) place CRH-1 into the context of a functional circuit by identifying postsynaptic retinal ganglion cells. These measurements will allow me determine whether CRH-1 cells could mediate feedforward inhibition in the inner retina. To examine the dynamics of gap-junctional coupling between nNOS-2 amacrine cells and the role of this network in visual processing. In preliminary experiments characterizing another genetically labeled amacrine cell, nNOS-2, I have discovered that these cells form an extensive coupled network. I will examine (A) whether nNOS-2 coupling is modulated by mean luminance and whether the modulatory signaling pathway involves dopamine or nitric oxide. I will also (B) determine how nNOS-2 coupling impacts visual response properties by measuring dendritic morphology and receptive fields in the same cells.