Dissecting the inhibitory architecture governing basal ganglia output

剖析控制基底神经节输出的抑制结构

• 批准号: 10304599
• 负责人: Rebekah Coleman Evans
• 金额: $ 24.9万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2024-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10304599
• 关键词: Affect; Anatomy; Architecture; Award; Axon; Basal Ganglia; Brain; Calcium; Cell Nucleus; Cells; Cellular Morphology; Characteristics; Computer Models; Contralateral; Corpus striatum structure; Deep Brain Stimulation; Dendrites; Disease; Dissection; Electrophysiology (science); Excitatory Synapse; Feedback; Genetic; Globus Pallidus; Glutamates; Goals; Image; Impairment; Interneurons; Knowledge; Learning; Location; Maintenance; Maps; Mentors; Methods; Midbrain structure; Mission; Morphology; Motion; Motor output; Movement; National Institute of Neurological Disorders and Stroke; Neurons; Output; Parkinson Disease; Pattern; Phase; Positioning Attribute; Public Health; Research; Signal Transduction; Source; Structure; Structure of subthalamic nucleus; Substantia nigra structure; Synapses; Techniques; Testing; Training; Work; base; cohesion; dopaminergic neuron; expectation; experience; experimental study; imaging study; implantation; inhibitory neuron; insight; motor disorder; motor impairment; nervous system disorder; optogenetics; pars compacta; programs; rabies viral tracing; reconstruction; relating to nervous system; stem cells; striosome; success; two-photon

The initiation and maintenance of organized movement through the basal ganglia is strongly influenced by its feed-forward and feedback inhibitory architecture. The substantia nigra pars compacta (SNc) and pedunculopontine nucleus (PPN) contribute to the overall output of the basal ganglia. Neurons in both structures degenerate in Parkinson's Disease, resulting in impaired motion. While treatments such as deep brain stimulation in the PPN (Snijders et al., 2016), and the implantation of stem cells into the SNc (Sonntag et al., 2018) have both met with variable success, their potential efficacy is constrained by a fundamental lack of knowledge about the circuitry of these two nuclei. The research proposed here will generate new insights into the function of inhibitory circuitry in these two nuclei and represents the first step toward a full understanding of the local and extended basal ganglia circuits which control organized motion. My long-term goal is to develop an independent research program focused on identifying cellular and network interactions that underlie basal ganglia control of motion. The overall objective of this K99/R00 application is to determine the extent to which local functional connectivity between genetically-defined subpopulations modulates basal ganglia output. My central hypothesis is that inhibition onto SNc and PPN neurons sculpts basal ganglia output by modulating excitatory gain. This hypothesis is based on preliminary two-photon uncaging, calcium imaging, optogenetic experiments, morphological reconstructions, and computational modeling. The rationale for this research is that once the circuit connectivity of the PPN and SNc is functionally mapped, we can begin to define the connections by which the basal ganglia select actions and control coordinated motion. To achieve my overall objective, I will work with my mentor, Dr. Zayd Khaliq and co-mentor, Dr. Chris McBain to learn and implement multi-channel optogenetic techniques and the simultaneous use of spatially-specific optogenetics with two photon glutamate uncaging and calcium imaging. These new techniques, in combination with my computational modeling and electrophysiological experience will allow me to complete my specific aims. During the mentored phase, I will complete aims 1 by performing functional tests of inhibitory inputs onto SNc dopamine neurons, including a comparison of the strength and location of inhibition from the striatal patch (striosome) compartments and the striatal matrix. In aim 2, I will test the functional consequences of dendrite-specific inhibition on the excitatory gain of SNc dopamine neurons. During the independent phase, I will utilize the same techniques to investigate the inhibitory circuitry of the PPN. In aim 3, I will perform functional tests of inhibitory inputs to the glutamatergic neurons of the PPN which have been identified with rabies tracing. In aim 4, I will define the intrinsic and genetic characteristics of a projection-defined subpopulation of PPN neurons. The proposed activities will generate fundamental knowledge about basal ganglia circuitry and will provide training in advanced two-photon and optogenetic techniques to compliment my current expertise in computational modeling and electrophysiology.

通过基底节的有组织运动的启动和维持受到其强烈的影响 前馈和反馈抑制结构。黑质致密部(SNC)和 桥脑脚核(PPN)对基底节的总输出量有贡献。两个结构中的神经元 在帕金森氏症中退化，导致运动障碍。而脑深部等治疗方法 刺激PPN(Snijders等人，2016)，以及将干细胞植入SNC(Sonntag等人， 2018)都取得了不同的成功，但它们的潜在疗效受到根本上缺乏 关于这两个原子核的电路的知识。这里提出的研究将产生新的见解 抑制回路在这两个核团中的功能，代表着通向全面理解 控制有组织的运动的局部和延伸的基底节回路。我的长期目标是开发一种 独立研究计划，专注于确定作为基础的蜂窝和网络交互 神经节控制运动。此K99/R00应用程序的总体目标是确定 基因定义的亚群之间的局部功能连接调节基底节的输出。我的 中心假说是，对SNC和PPN神经元的抑制通过调制形成基底节输出 兴奋的收获。这一假说是基于初步的双光子去功能化，钙成像，光发生 实验、形态重建和计算建模。这项研究的基本原理是 一旦从功能上映射了PPN和SNC的电路连接，我们就可以开始定义连接 基底节通过它来选择动作和控制协调运动。为了实现我的总体目标，我将 与我的导师Zayd Khaliq博士和共同导师Chris McBain博士合作学习和实施多渠道 光遗传学技术及其与双光子谷氨酸空间特异性光遗传学的同时应用 去钙化和钙化成像。这些新技术，结合我的计算模型和 电生理经验将使我能够完成我的特定目标。在指导阶段，我将 通过对黑质多巴胺神经元的抑制性输入进行功能测试来完成AIMS 1，包括 纹状体斑块(纹状体)和纹状体的抑制强度和位置的比较 纹状体基质。在目标2中，我将测试树突特异性抑制对兴奋性的功能影响。 黑质核多巴胺神经元的增益。在独立阶段，我将使用相同的技术来调查 PPN的抑制电路。在目标3中，我将对谷氨酸能抑制输入进行功能测试 狂犬病追踪已确定的PPN神经元。在目标4中，我将定义内在和遗传 投影定义的PPN神经元亚群的特征。拟议的活动将产生 基本的基础知识，并将提供高级双光子和 光遗传技术，以补充我目前在计算建模和电生理学方面的专业知识。