Origin, mechanism, and behavioral context of persistent firing in cortical parvalbumin-positive interneurons

皮质小白蛋白阳性中间神经元持续放电的起源、机制和行为背景

• 批准号: 10208989
• 负责人: Brian Theyel
• 金额: $ 19.65万
• 依托单位: BROWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-15 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10208989
• 关键词: Action Potentials; Advisory Committees; Anesthesia procedures; Animals; Astrocytes; Award; Axon; Behavioral; Brain; Brain Diseases; Calcium; Cell physiology; Cells; Cerebral cortex; Collaborations; Committee Members; Data; Dendrites; Disease; Doctor of Medicine; Doctor of Philosophy; Electroencephalography; Electrophysiology (science); Epilepsy; Fire - disasters; Fostering; Frequencies; Future; GABA transporter; Generations; Goals; Grant; Hippocampus (Brain); Image; Imaging Techniques; Interneurons; Investigation; Ion Channel; Lead; Link; Membrane; Mentors; Modeling; Molecular; Mus; N-Methyl-D-Aspartate Receptors; Neurons; Neurosciences; Parvalbumins; Pattern; Physicians; Physiologic pulse; Play; Population; Post-Traumatic Stress Disorders; Presynaptic Terminals; Research Personnel; Role; Schizophrenia; Scientist; Series; Signal Transduction; Site; Somatosensory Cortex; Source; Synapses; Technical Expertise; Techniques; Testing; Time; Training; Training Support; Travel; Vibrissae; Work; Writing; autism spectrum disorder; awake; brain cell; career; design; experimental study; in vivo; insight; meetings; neocortical; neural circuit; neuropsychiatric disorder; neurotransmitter release; novel; novel strategies; optogenetics; patch clamp; postsynaptic; postsynaptic neurons; prevent; receptor; responsible research conduct; synaptic inhibition; voltage; voltage sensitive dye

PROJECT SUMMARY Neurons, the basic processing and communicating units of the brain, typically use action potentials to transmit messages from a site near the cell body to neurotransmitter releasing terminals via axons. Action potentials can, in some cases, also travel backwards along the axon towards the cell body and dendrites; I refer to these here as ‘ectopics.’ Ectopics have been recorded in models of epilepsy, as well as in a small group of inhibitory interneurons under normal conditions. Recently, I discovered that nearly all parvalbumin positive (PV+) cells of the brain, which account for about half of neocortical inhibitory cells, can fire ectopics. We do not yet know exactly where in the axon ectopics are generated. In addition to not knowing where in the axon they come from, we also do not know what mechanism generates them. Finally, we do not know what conditions lead to ectopics in vivo. Here, I propose a series of experiments designed to answer these questions. In Aim 1, I will test whether receptors, ion channels, and cotransporters capable of depolarizing the presynaptic terminal are involved in ectopic generation. I will also use an ultra-rapid imaging technique to track action potentials as they travel through the axons of PV+ cells to directly confirm both where ectopics are generated and the number of synapses they trigger. In Aim 2 I will determine whether astrocytes, which envelop and modulate PV+ cell terminals, help elicit ectopics by blocking astrocyte-specific transporters and receptors, as well as by modulating intracellular astrocytic calcium stores and optogenetically depolarizing astrocytes. Finally, in Aim 3, I will undertake a series of experiments to detect ectopics in PV+ cells while mice are under anesthesia, and in various awake, behaving conditions. These experiments will discern both how, and in what contexts, ectopics are generated. Understanding the mechanisms of ectopic action potential initiation will yield new insights into the function of an important population of inhibitory interneurons. It may also reveal mechanisms that relate to brain disorders involving cortical hyperexcitability, providing novel targets for future investigations of circuit-level changes related to these brain disorders and, potentially, new approaches to treatment. This mentored award will support the training I need to establish an independent career as an academic physician-scientist. I will develop technical expertise in voltage-sensitive dye imaging and in vivo recording techniques under the direction of my mentor, Dr. Barry Connors, Ph.D., with input from advisory committee members Drs. Judy Liu, M.D., Ph.D. and Christopher Moore, Ph.D., who are leading experts in their fields. I will supplement this training with courses in the responsible conduct of research, molecular neuroscience techniques, and grant writing, along with attendance at local seminars and national meetings to disseminate my findings and foster collaborations. This training will help me achieve my goal of becoming an independent investigator exploring the neurocircuitry underlying neuropsychiatric disorders using cutting edge techniques.

项目摘要 神经元，基本的处理和通信大脑单位，通常使用动作电位传输 从细胞体附近的位点到神经递质通过轴突释放终端的消息。动作电位 在某些情况下，也可以沿轴突向后移动到细胞体和树突；我指的是 这里是“异位”。在癫痫的模型中以及一小部分抑制作用中都记录了异位 正常条件下的中间神经元。最近，我发现几乎所有白细胞蛋白阳性（PV+）细胞 大脑约占新皮质抑制细胞的一半，可以发射生态。我们还不知道 确切生成轴突生态中的位置。除了不知道它们来自哪里， 我们也不知道什么机制会产生它们。最后，我们不知道哪些条件会导致异位 体内。在这里，我提出了一系列旨在回答这些问题的实验。在AIM 1中，我将测试 受体，离子通道和能够分离突触前末端的受体，离子通道和共转运蛋白是 参与生态生成。我还将使用超优化成像技术来跟踪动作电位 他们穿过PV+细胞的轴突，直接确认生成生成的地方和 它们触发的突触数量。在AIM 2中，我将确定星形胶质细胞是否包膜和调节 PV+细胞终端，通过阻止星形胶质细胞特异性转运蛋白和接收器以及通过 调节细胞内星形细胞钙存储和光遗传学的星形胶质细胞。最后，目标 3，我将进行一系列实验，以检测小鼠在麻醉下的PV+细胞中，并且 在各种醒着的行为条件下。这些实验将辨别如何以及在什么情况下，Ecopics 生成。了解Ecopic Action潜在计划的机制将产生新的见解 重要的抑制性中间神经元人群的功能。它也可能揭示了相关的机制 脑部疾病涉及皮质过度兴奋性，为未来研究提供了新的目标 电路级的变化与这些脑部疾病以及可能的新方法有关。 这个重要的奖项将支持我为建立学术独立职业所需的培训 身体科学家。我将在电压敏感的染料成像和体内录制方面发展技术专长 Barry Connors博士博士在我的心理指导下的技术，并获得了咨询委员会的意见 会员博士。朱迪·刘（Judy Liu），医学博士克里斯托弗·摩尔（Christopher Moore）博士是其领域的主要专家。我 将通过负责任的研究，分子神经科学的负责任的课程来补充这种培训 技术和赠款写作，以及参加当地的半人选和国家会议以进行传播 我的发现和促进合作。这项培训将帮助我实现成为独立的目标 研究人员使用尖端技术探索神经通路神经心理疾病。