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.

项目总结 神经元是大脑的基本处理和交流单位，通常使用动作电位来传递 从细胞体附近的部位通过轴突传递到神经递质释放终端的信息。动作电位 在某些情况下，也可以沿着轴突向后移动到细胞体和树突；我指的是这些 在这里，我们将其称为“异地题材”。在癫痫模型中记录了异位，在一小群抑制性疾病中也记录到了异位。 正常情况下的中间神经元。最近，我发现几乎所有的小白蛋白阳性(PV+)细胞 大脑中约有一半的新皮质抑制细胞，可以激发异位。我们还不知道 确切地说，轴突异位是在哪里产生的。除了不知道它们来自轴突的哪里外， 我们也不知道是什么机制产生了它们。最后，我们不知道是什么条件导致了异位。 在活体内。在这里，我提出了一系列旨在回答这些问题的实验。在目标1中，我将测试 能够去极化突触前终末的受体、离子通道和共转运体是否 参与了异位的产生。我还将使用一种超快速成像技术来跟踪动作电位 它们通过PV+细胞的轴突直接确认异位产生的位置和 它们触发的突触数量。在目标2中，我将确定包被并调节的星形胶质细胞 PV+细胞终末，通过阻断星形胶质细胞特异性转运体和受体，以及通过 调节星形胶质细胞内钙储存和光遗传去极化星形胶质细胞。最后，在AIM中 3，我将进行一系列实验，在小鼠处于麻醉状态时检测PV+细胞的异位，以及 在各种清醒、行为的情况下。这些实验将辨别如何以及在什么背景下，话题 都是生成的。了解异位动作电位的启动机制将对 一组重要的抑制性中间神经元的功能。它还可能揭示出与 涉及皮质过度兴奋的大脑疾病，为未来的研究提供了新的靶点 与这些大脑疾病相关的电路水平的变化，以及潜在的新的治疗方法。 这个辅导奖将支持我建立一个独立的学术生涯所需的培训 医生兼科学家。我将开发电压敏感染料成像和活体记录方面的技术专长 在我的导师巴里·康纳斯博士的指导下，咨询委员会的意见 成员：医学博士朱迪·刘博士和博士克里斯托弗·摩尔博士，他们是各自领域的顶尖专家。我 将用负责任的研究行为、分子神经科学等课程来补充这一培训 技术和赠款书写，以及出席地方研讨会和国家会议以传播 我的发现和促进合作。这次培训将帮助我实现成为一名独立人士的目标 研究人员使用尖端技术探索神经精神障碍背后的神经回路。