Understanding the Developmental Mechanisms that Ensure Robustness in Neuronal Patterning

摘要：在相互竞争的神经元回路活动之间建立平衡对于 行为的协调。我们建议研究发展战略，确保 在神经系统中建立这种平衡。对脊椎动物胚胎神经系统的研究已经 结果表明，相关的活动通过类似于以下机制的机制来形成结构和输出新生电路 学习。脊椎动物大脑的规模和复杂性使得识别 管理这种学习或驱动电路优化以达到平衡输出的机制。这个 秀丽隐杆线虫神经系统的小体积和不变性使研究它们成为可能 在脊椎动物中不可能有专一性的过程。使用开发的首批功能之一 以线虫胚胎中的环路为模型，我将研究如何在 发展神经系统，并确定确保其健壮性的发育机制 平衡。为了实现这一目标，我提出了以下具体目标：1)识别IL1神经元的模型 在胚胎头部运动模式中的作用。2)自动化并改进以下方法 利用红外激光诱导的热休克以单细胞分辨率控制转基因表达。和3)至 确定IL1电路建立和维持平衡输出以产生 协调动作。为了实现这一点，我开发了一种实时细胞跟踪系统，它可以自动 在胚胎发育过程中识别靶细胞，并可以控制单细胞的行为 最近在《发展》杂志上发表的一篇论文中描述了光学微扰，如激光消融 单细胞热休克，或将在AIM 2中开发的单细胞热休克。我还开发了一个自动图像 分析流水线，使我能够跟踪和测量早期胚胎的运动模式 已经确定了头部运动模式的神经元起源，并利用神经元的基因突变 功能，表明这种模式是由神经元输入定义的。我相信，这项工作将提供重要的 对胚胎神经系统模式的洞察及其对我们理解 一些神经发育障碍的电路层面的起源。为了扩大我作为生物学家的训练， 作为我广泛的技术培训和专业知识的补充，我将作为一个 线虫胚胎专家包志荣博士实验室博士后研究员 开发，并在一个由经验丰富的咨询委员会组成的完善的咨询委员会的指导下 生物学家和神经学家。我设计了一个有组织的计划，以进一步加强我的科学培训和支持 我的职业发展为独立的职业生涯做准备。斯隆·凯特琳学院和三人组- 威尔·康奈尔医学院和洛克菲勒大学的机构社区提供了无与伦比的 智力环境支持我的科学成长和走向独立的进步。

Abstract: Establishing a balance between the activities of competing neuronal circuits is essential to the coordination of behaviors. We propose to investigate the developmental strategies that ensure the establishment of this balance in the nervous system. Studies of the vertebrate embryonic nervous system have shown that correlated activity patterns the structure and output nascent circuits through mechanisms akin to learning. The scale and complexity of vertebrate brains has made it challenging to identify the rules which govern this learning or the mechanisms which drive optimization of the circuit toward a balanced output. The small size and invariance of the Caenorhabditis elegans nervous system make it possible to study these processes with specificity not possible in vertebrates. Using the development of one of the first functional circuits in the C. elegans embryo as a model, I will study how functional balance is established in the developing nervous system and identify the developmental mechanisms that ensure the robustness of this balance. To accomplish this goal, I propose the following specific aims: 1) To identify the models of IL1 neuron function in the patterning of embryonic head movement. 2) To automate and improve an approach for controlling transgene expression with single cell resolution by infrared laser-induced heatshock. And 3) To determine the mechanisms by which the IL1 circuit establishes and maintains a balanced output to produce coordinated movements. To enable this, I have developed a real-time cell tracking system which automates the identification of targeted cells during embryonic development and can control the conduct of single cell optical perturbations such as laser ablation as described in a recently published paper in Developmental Cell or, as will be developed in Aim 2, single cell heatshock. I have also developed an automated image analysis pipeline which allows me to track and measure movement patterns in the early embryo with which I have identified the neuronal origins of patterned head movement and, using genetic mutants of neuronal function, shown that this patterning is defined by neuronal input. I believe that this work will provide important insights into the patterning of the embryonic nervous system with implications for our understanding of the circuit-level origins of some neurodevelopmental disorders. In order to expand my training as a biologist and complement my broad technical training and expertise, I will carry out the mentored phase of this award as a postdoctoral Research Associate in the laboratory of Dr. Zhirong Bao, an expert on C. elegans embryonic development, and under the mentorship of a well-accomplished advisory committee comprised of experienced biologists and neuroscientists. I have designed a structured plan to further my scientific training and support my career development to prepare for an independent career. The Sloan Kettering Institute and the tri- institutional community at Weill Cornell Medical College and The Rockefeller University provide an unparalleled intellectual environment to support my scientific growth and progress towards independence.