Homeostatic Plasticity Mechanisms Support Brain Function in Vivo

 描述（由申请人提供）：“自我平衡”机制用于稳定系统的关键参数，非常类似于恒温器用于稳定建筑物中的温度。在神经元中，稳态突触可塑性被认为可以抵消赫布可塑性机制的不稳定影响，赫布可塑性机制是突触连接的活性依赖性细化的基础。据推测，严重的人类病理是由神经元稳态机制受损引起的，包括阿尔茨海默病、癫痫和Rett综合征。在这个领域取得进展的一个重要障碍是我们几乎完全缺乏对完整大脑内稳态可塑性的了解。我建议研究稳态突触可塑性如何支持自由行为动物的大脑功能和行为。这项提案中的研究将集中在突触缩放上，这是体外神经元活动稳态的最佳理解机制之一。首先，在指导（K99）组件期间执行的工作将定义突触缩放在体内放电率稳态中的功能作用。为了做到这一点，我将利用病毒介导的基因转移来阻断皮质神经元子集中的突触缩放，并测试长期感觉剥夺的稳态反应。接下来，在指导和独立阶段进行的工作将测试睡眠对于体内稳态可塑性的表达是必要的假设。这将通过两个步骤来实现：（i）在稳态可塑性的正常表达中检查神经调节状态特异性和/或昼夜节律模式，以及（ii）在自由行为动物中放电率稳态出现期间的关键时间，调节状态将被破坏。最后，在独立阶段（R 00），我将评估关于稳态可塑性的核心预测：这些稳态机制有助于抵消赫布可塑性在经验依赖的网络细化（即学习和发展）过程中固有的不稳定影响。在这项工作中，我将确定突触缩放在a）皮层网络中信息传递的发展和B）皮层依赖行为的发展中的作用。拟议的研究将有助于理解和治疗理论上涉及失调的稳态可塑性机制的疾病。此外，这些数据将为睡眠剥夺的影响提供新的见解。最后，这项工作将确定健康大脑中稳态可塑性所需的参数，并深入了解稳态可塑性在高级大脑功能中的作用。候选人的近期和长期职业目标迄今为止，我的研究生培训和博士后经验为我提供了与本文所提出的研究相关的方法和概念的坚实背景。我的长期研究目标是了解失调的稳态机制在神经系统疾病和疾病中的作用，并揭示稳态可塑性对正常大脑功能的贡献。 为了完成这项工作，我将需要在各种技术以及智力，专业和学术指导的额外培训。布兰代斯大学的环境与我的导师，我的科学和职业小组委员会的成员以及合作者的奉献精神和专业知识相结合，为在研究型大学追求学术终身职位提供了完美的基础。在体内分子生物学，计算神经科学，行为和技术发展的综合培训将提供必要的最后要素，我开始一个独立的职业生涯调查的作用，稳态可塑性在正常的大脑功能和疾病。研究职业发展计划的关键要素。本申请指导阶段所述的研究将在Brandeis大学在Gina Turrigiano博士的监督下进行。Turrigiano实验室开创了突触缩放的研究，是稳态可塑性领域公认的领导者。我已经组建了一个科学和职业咨询小组委员会，它在科学上是多样化的，致力于我作为一个独立科学家的发展。Stephen货车Hooser博士将提供动物视觉、计算技术和体内光遗传学操作方面的专业知识。Avital Rodal博士将提供分子生物学技术方面的专业知识，并监督对AMPAR贩运操纵的解释。Eve Marder博士将提供计算神经科学，实验设计和理论方面的专业知识。除了这次培训，我将在我的合作者Timoth Gardner博士（波士顿大学）的实验室里花两个月的时间学习先进的体内神经科学所必需的尖端技术制造。最后，我将通过定期参加国际会议和研究研讨会来支持这些活动，以发展我的国际影响力，并继续我在相关主题方面的教育。当我开始我的职业生涯时，我的委员会将在早期职业问题上提供持续的支持，进一步支持我向独立的过渡。

 DESCRIPTION (provided by applicant): A "homeostatic" mechanism functions to stabilize a key parameter of a system, much like a thermostat functions to stabilize the temperature in a building. In neurons, homeostatic synaptic plasticity is believed to counteract the destabilizing influence of Hebbian-plasticity mechanisms that underlie the activity-dependent refinement of synaptic connectivity. It is postulated that severe human pathologies arise from impaired mechanisms of neuronal homeostasis, including Alzheimer's disease, epilepsy, and Rett syndrome. A significant barrier to progress in this field is our nearly complete lack of insight ino homeostatic plasticity in the intact brain. I propose to study how homeostatic synaptic plasticity supports brain function and behavior in the freely behaving animal. Research in this proposal will focus on synaptic scaling, one of the best-understood mechanisms of neuronal activity homeostasis in vitro. First, work performed during the mentored (K99) component will define a functional role for synaptic scaling in firing rate homeostasis in vivo. To do this, I will utilizeviral-mediated gene transfer to block synaptic scaling in a subset of cortical neurons and test the homeostatic response to long-term sensory deprivation. Next, work performed during the mentored and independent phases will test the hypothesis that sleep is necessary for the expression of homeostatic plasticity in vivo. This will be achieved in two steps: (i) neuromodulatory state-specific and/or circadian patterns will be examined in the normal expression of homeostatic plasticity, and (ii) modulatory states will be disrupted at key times during the emergence of firing rate homeostasis in the freely behaving animal. Finally, during the independent stage (R00), I will assess the core prediction about homeostatic plasticity: those homeostatic mechanisms serve to offset the inherently destabilizing effects of Hebbian plasticity during experience dependent refinement of networks (i.e. learning and development). In this work, I will determine the role of synaptic scaling in a) the development of information transmission in cortical networks, and b) the development of cortex-dependent behavior. The proposed research will be instrumental for the understanding and treatment of disorders that are theorized to involve dysregulated homeostatic plasticity mechanisms. Further, these data will provide novel insight into the effects of sleep deprivation. Finally, this work will identify parameters necessary for homeostatic plasticity in the healthy brain and provide insight into the role of homeostatic plasticity in higher-level brain functions. Candidate's immediate and long-term career goals my graduate training and postdoctoral experience thus far have provided me with a solid background in the methods and concepts related to the research proposed here. My long-term research goal is to understand the role of dysregulated homeostatic mechanisms in neurological disorders and disease, and to unravel the contributions of homeostatic plasticity to normal brain function. In order to complete this work, I will need additional training in a variet of techniques as well as intellectual, professional, and academic guidance. The environment at Brandeis University combined with the dedication and expertise of my mentor, the members of my scientific and career subcommittee, and collaborators provides a perfect base from which to pursue an academic tenure-track position at a research university. The combined training in in vivo molecular biology, computational neuroscience, behavior, and technology development will provide the final elements necessary for me to begin an independent career investigating the role of homeostatic plasticity in normal brain function and disease. Key elements of the research career development plan. The research described in the mentored phase of this application will be performed at Brandeis University under the supervision of Dr. Gina Turrigiano. The Turrigiano laboratory pioneered the study of synaptic scaling and is a recognized leader in the field of homeostatic plasticity. I have assembled a scientific and career advisory subcommittee that is scientifically diverse and dedicated to my development as an independent scientist. Dr. Stephen Van Hooser will provide expertise in animal vision, computational techniques, and in vivo optogenetic manipulations. Dr. Avital Rodal will provide expertise in molecular biology techniques and oversee the interpretation of AMPAR trafficking manipulations. Dr. Eve Marder will provide expertise in computational neuroscience, experimental design, and theory. In addition to this training, I will spend two months in the laboratory of my collaborator, Dr. Timoth Gardner (Boston University) learning cutting-edge technology fabrication necessary for the advancement of in vivo neuroscience. Finally, I will support these activities with regular attendance of international meetings and research seminars to develop an international presence for myself and continue my education in relevant topics. As I begin my career, my committee will provide ongoing support in early career issues, further supporting my transition to independence.