Discovery of functional cell types in the inferior colliculus with combined molecular-genetic and electrophysiological approaches

结合分子遗传学和电生理学方法发现下丘功能细胞类型

基本信息

批准号：
9300564
负责人：
Nace L Golding
金额：
$ 18.97万
依托单位：
UNIVERSITY OF TEXAS AT AUSTIN
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-04-01 至 2019-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9300564
关键词：
Address Affect Anatomy Area Auditory Brain Calcium-Binding Proteins Cell Nucleus Cells Cellular Morphology Cereals Characteristics Classification Communication impairment Complement Cues Data Electrophysiology (science)Elements Exhibits Fluorescence Foundations Future Genetic Genetic Techniques Gerbils Goals Inferior Colliculus Interneurons Label Light Lighting Location Maps Mediating Midbrain structure Molecular Genetics Morphology Nature Neurons Pathway interactions Pattern Phenotype Physiological Physiology Population Property Proteins Recombinant adeno-associated virus (rAAV)Role Slice Stream Structure Synapses Testing Tinnitus Training Activity Viral Virus Whole-Cell Recordings auditory pathway auditory thalamus calbindin calbindin-D28K cell type excitatory neuron experimental study genetic approach hearing impairment in vivo inhibitory neuron intersectionality neural circuit neurochemistry novel optogenetics patch clamp promoter sound tool

项目摘要

Project Summary The central nucleus of the inferior colliculus (ICC) is a midbrain nucleus that serves as a pivotal point of convergence for a large number of ascending and descending auditory pathways. Understanding how computations carried out in the ICC relate to the underlying circuitry has been unusually difficult, in large part due to the lack of clear definitions of cell types. Indeed, there appears to be no correlations between intrinsic firing properties and cell morphology, even across excitatory and inhibitory cells. We propose that functionally distinct classes of neurons in the ICC can be identified and genetically accessed using viruses with promoters to different neurochemical markers. To address this hypothesis, we will combine electrophysiological and anatomical approaches with interdependent recombinant adeno-associated viruses (rAAV) targeting excitatory and inhibitory classes of calbindin D-28k ICC neurons (CB-excitatory and CB- inhibitory). CB is a calcium binding protein expressed in subsets of neurons of the ICC and in many other brain areas. Our preliminary results show that viruses carrying a CB promoter element target ICC neurons that exhibit a single firing phenotype, and that these neurons may comprise both excitatory and inhibitory subclasses. In Aim 1, we will combine in vivo labeling of ICC neurons with rAAV viruses, fluorescence guided patch recordings in IC slices, and anatomical analyses to fully characterize the two pools of CB neurons, including their physiology, morphology and axonal projections. In parallel, labeled neurons will be characterized according to their complement of expressed neurochemical markers. In Aim 2, we will use our molecular-genetic tools to drive channelrhodopsin-2 selectively in CB-excitatory or CB-inhibitory neurons. We will use structured illumination to map CB neurons' local inputs and targets in the ICC as well as to facilitate paired whole-cell patch recordings from connected neuron pairs, enabling characterization of synaptic properties between physiologically identified network partners. These experiments will serve as a blueprint for identifying and characterizing other functionally distinct circuits in the ICC. Our goal is to establish a foundation for future studies involving cell-specific optogenetic manipulations in vivo, where we can assess the roles of CB neurons and other defined ICC cell types in auditory computations.

项目概要下丘中央核（ICC）是一个中脑核，是大脑的枢轴点。大量上行和下行听觉通路的汇聚。了解如何在 ICC 中进行的与底层电路相关的计算在很大程度上异常困难由于缺乏细胞类型的明确定义。事实上，内在因素之间似乎不存在相关性。放电特性和细胞形态，甚至跨越兴奋性和抑制性细胞。我们建议可以识别和遗传访问 ICC 中功能不同的神经元类别使用具有不同神经化学标记启动子的病毒。为了解决这个假设，我们将结合相互依赖的重组腺相关病毒的电生理学和解剖学方法 (rAAV) 靶向钙结合蛋白 D-28k ICC 神经元的兴奋性和抑制性类型（CB-兴奋性和 CB- 抑制）。 CB 是一种钙结合蛋白，在 ICC 神经元亚群和许多其他大脑中表达地区。我们的初步结果表明，携带 CB 启动子元件的病毒靶向 ICC 神经元，表现出单一放电表型，并且这些神经元可能同时包含兴奋性和抑制性子类。在目标 1 中，我们将结合体内 ICC 神经元标记与 rAAV 病毒、荧光引导 IC 切片中的补丁记录和解剖分析，以充分表征两个 CB 神经元池的特征，包括它们的生理学、形态学和轴突投射。同时，标记的神经元将被根据表达的神经化学标记物的补充来表征。在目标 2 中，我们将使用我们的在 CB 兴奋性或 CB 抑制性神经元中选择性驱动通道视紫红质 2 的分子遗传工具。我们将使用结构化照明来映射 CB 神经元的局部输入和 ICC 中的目标，并促进来自连接的神经元对的配对全细胞贴片记录，从而能够表征突触生理上识别的网络伙伴之间的属性。这些实验将作为识别和表征其他功能不同的电路的蓝图在国际刑事法院。我们的目标是为未来涉及细胞特异性光遗传学的研究奠定基础体内操作，我们可以评估 CB 神经元和其他定义的 ICC 细胞类型在听觉计算。