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.

摘要 这个提议的目标是了解视觉信号是如何从外层视网膜传递到内层视网膜的 通过锥双极细胞（CBC），重点是详细的突触机制和功能电路之间 形态学和生理学鉴定的锥体双极细胞类型和特定的神经节和无长突细胞 在整个安装小鼠视网膜的类型。这项调查的动机是一个重要的观察， 尽管最近的转录组学、连接组学和成像研究显著地推进了我们的研究， 了解双极细胞的分类和解剖结构，我们的详细生理学知识， 由这些分类的CBC类型形成的突触和回路仍然非常有限。为了解决这个 在我们对视网膜处理的理解中，我们开发了一种新的实验方法， 双突触前和突触后膜片钳记录从对形态学鉴定的CBC类型， 神经节细胞类型在整个安装小鼠视网膜结合双光子光学记录和 基因编码的谷氨酸和钙传感器的靶向表达。这种方法使我们能够将 每种形态CBC类型的解剖结构及其内在和感受野生理学， 更重要的是，在电压钳条件下，以毫秒级的分辨率直接测量突触 在结构完整的视网膜中，从识别的CBC类型到其突触后靶点的传递。我们的初步 结果揭示了CBC新的动力学和电路特性，提示了突触传递的新机制。 整合使用化学和电突触传递。根据这些初步结果，我们 提出了一种双模式突触机制，CBCs通过该机制既传递直接突触信号又传递间隙信号。 连接耦合网络向其突触后靶点发送信号。这一假设的机制将得到检验 三个具体目标。目的1、双膜片钳技术表征突触传递和突触后膜电位 形态学鉴定的CBC类型和弥散神经节细胞类型（W3）之间的功能连接， 整个视网膜目的2，了解信号背后的化学和电突触相互作用 从鉴定的CBC类型到全载片视网膜中的W3细胞的传输。目标3，确定功能 不同CBC突触传递方式对弥散和窄层突触后靶点影响 细胞这项研究的结果有望为突触机制和功能提供新的见解。 在哺乳动物视网膜的锥双极细胞类型的电路，并阐明化学和电突触 一般来说，CNS中的整合。