Synaptic Function and Organization of the Mammalian Retina

描述（由申请人提供）：本申请旨在研究成熟兔视网膜中胆碱能（starburst）无突细胞和方向选择性神经节细胞（DSGCs）突触整合的机制，其总体目标是阐明哺乳动物视网膜内部复杂视觉处理，特别是运动方向检测的突触和细胞机制。提出的研究是基于包括我们在内的几个实验室最近的发现，这些发现强烈地表明星爆细胞在方向选择性（DS）的产生中起着关键作用。这些研究将关于DS机制的关键未知问题转移到了DSGCs的上游，并提出了一些需要新水平实验来回答的基本问题。在这里，我们确定了3个特定的目标，将测试关于星爆细胞突触、细胞和网络功能背后机制的2个中心假设：1)确定星爆细胞之间的突触相互作用机制，2)确定星爆远端过程中定向选择性光反应的突触机制，3)确定星爆和神经节细胞之间的突触相互作用机制。我们将使用一种功能强大的全体兔视网膜制剂，它可以整合星暴细胞和DS神经节细胞的双膜片钳记录，同时进行闪光光解（UV解锁）和双膜片钳，同时进行钙成像、膜片钳和光刺激。将这些尖端技术应用于活体哺乳动物视网膜的能力将使我们能够收集以前在其他实验环境中无法获得的关键信息。我们的实验方法是独特的，因为它将直接和系统地测量DS电路关键组件之间的突触相互作用，它将使用详细的突触生理学来解释从相同的已识别神经元记录的光响应特性。

DESCRIPTION (provided by applicant): This application proposes to study mechanisms of synaptic integration by cholinergic (starburst) amacrine and direction-selective ganglion cells (DSGCs) in the mature rabbit retina with an overall goal to elucidate synaptic and cellular mechanisms underlying complex visual processing in the inner mammalian retina, particularly the detection of motion direction. The proposed studies are based on recent findings of several labs, including ours, that strongly suggest a critical role of starburst cells in the generation of direction selectivity (DS). These studies moved the key unknown issues regarding DS mechanisms to sites upstream of DSGCs and raised some fundamental questions that require a new level experimentation to answer. Here we identify 3 specific aims that will test 2 central hypotheses about the mechanisms underlying the synaptic, cellular, and network functions of starburst cells: 1) to determine the mechanisms of synaptic interaction among starburst cells, 2) to determine the synaptic mechanism of direction-selective light responses in starburst distal processes, 3) to determine the mechanisms of synaptic interaction between starburst and ganglion cells. We will use a powerful wholemount rabbit retinal preparation, which allows the integration of dual patch-clamp recording from starburst cells and DS ganglion cells, simultaneous flash photolysis (UV uncaging) and dual patch clamp, and simultaneous calcium imaging, patch clamp, and light stimulation. The ability to apply these cutting-edge techniques to a living mammalian retina will enable us to gather critical information previously unattainable in other experimental settings. Our experimental approach is unique in that it will directly and systematically measure synaptic interactions among key components of the DS circuit and it will use detailed synaptic physiology to explain the light response properties recorded from the same identified neurons.