Synaptic mechanisms and circuitry of retinal interneurons

视网膜中间神经元的突触机制和电路

• 批准号: 10737233
• 负责人: Z JIMMY ZHOU
• 金额: $ 51.71万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-30 至 2028-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10737233
• 关键词: Address; Amacrine Cells; Anatomy; Cell physiology; Cells; Chemicals; Classification; Cone; Coupled; Diffusion; Disease; Functional disorder; Gap Junctions; Glutamates; Goals; Image; Impairment; Interneurons; Investigation; Kinetics; Knowledge; Light; Measures; Morphology; Mus; Neurons; Optics; Output; Photoreceptors; Physiological; Physiology; Property; Resolution; Retina; Role; Signal Transduction; Synapses; Synaptic Transmission; Testing; Visual; cell type; ganglion cell; imaging study; insight; millisecond; neuronal circuitry; novel; patch clamp; postsynaptic; presynaptic; receptive field; response; sensor; spatiotemporal; starburst; transcriptomics; transmission process; two-photon; visual information; voltage clamp

Abstract The goal of this proposal is to understand how visual signals are transmitted from the outer to the inner retina through cone bipolar cells (CBC), with a focus on detailed synaptic mechanisms and functional circuits between morphologically and physiologically identified cone bipolar cell types and specific ganglion and amacrine cell types in the whole-mount mouse retina. This investigation is motivated by an important observation that, although recent transcriptomic, connectomic, and imaging studies have significantly advanced our understanding of bipolar cell classification and anatomical structure, our knowledge of the detailed physiology of the synapses and circuits formed by these classified CBC types remains very limited. To address this fundamental gap in our understanding of retinal processing, we developed a new experimental approach, using dual pre- and post-synaptic patch-clamp recording from pairs of morphologically identified CBC types and ganglion cell types in the whole-mount mouse retina in conjunction with two-photon optical recording and targeted expression of genetically encoded glutamate and Ca sensors. This approach allowed us to correlate the anatomical structure of each morphological CBC type with its intrinsic and receptive-field physiology and, more importantly, to directly measure, at a millisecond resolution and under voltage-clamp condition, synaptic transmission from identified CBC types to their postsynaptic targets in a structurally intact retina. Our preliminary results revealed novel kinetic and circuit properties of CBC that suggested a new mechanism of synaptic integration using both chemical and electrical synaptic transmission. Based on these preliminary results, we propose a dual-mode synaptic mechanism by which CBCs transmit both a direct synaptic signal and a gap junction-coupled network signal to their postsynaptic targets. This hypothesized mechanism will be tested through the three Specific Aims. Aim 1, dual patch-clamp characterization of synaptic transmission and functional connectivity between morphologically identified CBC types and a diffused ganglion cell type (W3) in the whole-mount retina. Aim 2, understand the chemical and electrical synaptic interactions underlying signal transmission from identified CBC types to W3 cells in the whole-mount retina. Aim 3, determine the functional impact of different modes of CBC synaptic transmission on diffused and narrowly stratified postsynaptic target cells. Results from this study are expected to provide novel insights into the synaptic mechanisms and functional circuitry of cone bipolar cell types in the mammalian retina and shed light on chemical and electrical synaptic integration in the CNS in general.

抽象的 该提案的目标是了解视觉信号如何从外层视网膜传输到内层视网膜 通过锥体双极细胞 (CBC)，重点关注细胞之间的详细突触机制和功能回路 形态学和生理学上鉴定的视锥双极细胞类型以及特定的神经节和无长突细胞 类型在整个安装的鼠标视网膜中。这项调查的动机是一个重要的观察结果， 尽管最近的转录组学、连接组学和影像学研究显着推进了我们的研究 了解双极细胞分类和解剖结构，我们对详细生理学的了解 由这些分类的 CBC 类型形成的突触和电路仍然非常有限。为了解决这个问题 为了弥补我们对视网膜处理理解的根本差距，我们开发了一种新的实验方法，使用 突触前和突触后双重膜片钳记录，来自形态学鉴定的 CBC 类型对和 与双光子光学记录相结合的整体小鼠视网膜中的神经节细胞类型 基因编码的谷氨酸和 Ca 传感器的靶向表达。这种方法使我们能够关联 每种形态学 CBC 类型的解剖结构及其内在和感受野生理学， 更重要的是，以毫秒分辨率和电压钳条件下直接测量突触 从已识别的 CBC 类型传输到结构完整的视网膜中的突触后目标。我们的初步 结果揭示了 CBC 的新动力学和电路特性，提出了突触的新机制 使用化学和电突触传递进行整合。根据这些初步结果，我们 提出了一种双模式突触机制，通过该机制 CBC 传输直接突触信号和间隙信号 连接耦合网络信号发送至突触后目标。这个假设的机制将被测试 通过三个具体目标。目标 1，突触传递和双膜片钳表征 形态学鉴定的 CBC 类型与弥散性神经节细胞类型 (W3) 之间的功能连接 整个视网膜。目标 2，了解信号背后的化学和电突触相互作用 从已识别的 CBC 类型传输到整体视网膜中的 W3 细胞。目标3，确定功能 不同CBC突触传递模式对弥散和窄分层突触后目标的影响 细胞。这项研究的结果预计将为突触机制和功能提供新的见解。 哺乳动物视网膜中视锥双极细胞类型的电路并揭示化学和电突触 一般而言，中枢神经系统的整合。