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

• 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
• 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

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.

项目摘要 下丘丘（ICC）的中央核是一种中脑核，作为关键点 大量上升和下降的听觉途径的收敛。了解如何 在ICC中进行的计算与基础电路有关，这在很大程度上非常困难，在很大程度上 由于缺乏细胞类型的明确定义。确实，固有之间似乎没有相关性 即使在兴奋性和抑制性细胞中，也发射特性和细胞形态。 我们建议可以识别和遗传访问ICC中功能上不同的神经元类别 将病毒与启动子一起用于不同的神经化学标记。为了解决这一假设，我们将结合 具有相互依存的重组腺相关病毒的电生理和解剖方法 （RAAV）针对Calbindin D-28K ICC神经元的兴奋性和抑制类别（CB-兴趣和CB-） 抑制）。 CB是一种钙结合蛋白，该蛋白在ICC和许多其他大脑的神经元子集中表达 区域。我们的初步结果表明，携带CB启动子元素靶向ICC神经元的病毒是 表现出单个发射表型，这些神经元可能构成兴奋性和抑制性 子类。在AIM 1中，我们将在ICC神经元的体内标记与RAAV病毒，荧光引导 IC切片中的补丁记录和解剖分析，以完全表征CB神经元的两个池， 包括它们的生理学，形态和轴突预测。同时，标记的神经元将是 根据它们表达的神经化学标记的补充。在AIM 2中，我们将使用我们的 在CB兴奋剂或CB抑制性神经元中选择性地驱动ChannelRhopopsin-2的分子遗传学工具。我们 将使用结构化照明来映射CB神经元在ICC中的局部输入和目标以及促进 来自连接的神经元对的配对的全细胞斑块记录，使突触表征 生理确定的网络合作伙伴之间的属性。 这些实验将用作识别和表征其他功能不同电路的蓝图 在ICC中。我们的目标是为涉及细胞特异性光遗传学的未来研究建立基础 在体内操作，我们可以评估CB神经元和其他定义的ICC细胞类型的作用 听觉计算。