Intersectional genetic dissection of inner retinal circuits

项目摘要 哺乳动物视网膜中的视觉信息被分成功能和解剖学上的专门通道 用于并行处理。小鼠视网膜含有大约40种视网膜神经节细胞(RGC)。每个人 类型可以根据它们的光响应的时空特性和它们的独特之处来区分 形态特征。每个RGC类型都执行复杂的神经计算来传达特定的方面 视觉场景到大脑的视网膜受体区域。这些复杂的计算产生于相互作用 兴奋性和抑制性信号之间的差异集中在不同类型RGC的树突上。这些计算 由于我们对不同的抑制性类别所扮演的角色缺乏了解，因此在很大程度上仍未得到解决 中间神经元，无长突细胞(ACS)。这项研究的目的是表征反应特性， 新发现的无长突细胞CK2-AC1的功能联系和视觉处理作用。这 Project使用了在小鼠视网膜上可用的强大的交叉策略。具体而言，CaMk2a-TTA驱动器 线与他莫昔芬可诱导的Slc32a1-iCreer驱动器线交叉，以专门标记CK2-AC1细胞。这个 通过GCaMP6f、ChR2和DREADDS的遗传标记，探讨了CK2-AC1的反应特性。2- 光子成像用于记录树突状钙信号，以测量感受场特性并确定 功能选择机制。结果表明，CK2-AC1是一种甘氨酸能偏心细胞 定向(OS)和物体运动敏感(OMS)。ChR2定位实验表明，CK2-AC1 为一种名为HD1-RGC的开关定向选择性RGC提供甘氨酸能抑制 其他类型的RGC(HD2、F-mini Off和G4)。最后，对CK2-AC1在视觉加工中的功能作用进行了讨论 通过使用DREADDS可逆地检查到可逆地静默活动。CK2-AC1同时提供正交和 对HD1和HD2-RGC的OMS抑制。这些发现表明，CK2-AC1是一种多任务AC 赋予不同类型的RGC方向选择性和对象运动敏感度。这项工作将增强我们的 了解特定的视网膜回路，将为内部的遗传解剖提供一个通用的模板 视网膜回路。

Project Summary Visual information in the mammalian retina is segregated into functionally and anatomically specialized channels for parallel processing. The mouse retina contains approximately ~40 retinal ganglion cell (RGC) types. Each type can be distinguished based on the spatiotemporal properties of their light responses and their distinctive morphological features. The RGC types each perform complex neural computations to convey specific aspects of the visual scene to retino-recipient areas of the brain. These complex computations arise from an interplay between excitatory and inhibitory signals centered on the dendrites of individual RGC types. These computations remain largely unresolved due to our lack of knowledge of the roles played by a diverse class inhibitory interneurons, the amacrine cells (ACs). The purpose of this study is to characterize the response properties, functional connections, and visual processing roles of a newly discovered amacrine cell, the CK2-AC1. This project uses powerful intersectional strategies available in the mouse retina. Specifically, a CaMk2a-tTA driver line is crossed with a tamoxifen inducible Slc32a1-iCreER driver line to exclusively label CK2-AC1 cells. The response properties of CK2-AC1 are probed by genetically labeling with GCaMP6f, ChR2, and DREADDS. 2- photon imaging is used to record dendritic Ca2+ signals to measure receptive field properties and determine feature selectivity mechanisms. The results show that CK2-AC1 is a glycinergic OFF center cell that is both orientation (OS) and object-motion sensitive (OMS). Experiments with ChR2 mapping revealed that CK2-AC1s provide glycinergic inhibition to a type of ON-OFF orientation selective RGC named HD1-RGC along with several other types of RGCs (HD2, F-minioff, and G4). Finally, the functional roles of CK2-AC1 in visual processing were examined by using DREADDs to reversibly to reversibly silence activity. CK2-AC1 provided both orthogonal and OMS suppression to HD1- and HD2-RGCs. These findings indicate that CK2-AC1 is a multi-tasking AC that confers orientation selectivity and object motion sensitivity on different RGC types. This work will enhance our understanding of specific retinal circuits and will provide a general template for a genetic dissection of inner retinal circuits.