Mechanisms of respiratory-related rhythmic motor activity and plasticity in the avian brain stem

描述（由申请人提供）：我们研究团队的长期目标是了解控制维持生命的自主呼吸模式的脑干运动回路如何发展，成熟和维持有节奏的神经活动。确定这些回路如何对异常环境和压力作出反应也是相关的。本项目拟采用一种新的实验模型系统来探索分离斑胸草雀脑干早期发育过程中呼吸相关中枢模式发生器（CPGs）的位置、突触生理学和可塑性。鸟类胚胎模型是唯一易于处理的实验操作，并提供了无与伦比的访问中枢神经网络在产前发育。我们将使用解剖学技术、神经细胞活动和药理学来验证我们在理解正常呼吸行为和呼吸相关神经病理学背景下的假设，其中控制正常节律和运动模式的脑干结构的改变或丧失可能导致新生儿和成人发病率和死亡率增加。重要的是，来自该提案的资金将向学生介绍爱达荷州立大学（ISU）基于生物医学的研究，使用动手实验室经验和各种专业和科学实践的重点个人培训。我们寻求解决与发育神经生物学和呼吸控制领域相关的三个关键方面：1。空间分离呼吸相关脑干CPGs的鉴定。目的1将测试禽旁歧义核（PAm）和后歧义核（RAm）在自动呼吸节律的神经发生中的作用。从历史上看，体外研究主要集中在吸气阶段。然而，呼吸循环包括吸气和呼气。由于鸟类即使在休息时也会主动吸气和主动呼气，我们假设鸟类胚胎在内部孵化阶段（即开始连续呼吸空气时）产生两个独立但耦合的cpg呼吸节律，类似于人类运动时需要高水平的通气驱动的情况。2. 禽类脑干突发和模式形成的机制。目的2将验证鸟类呼吸相关的CPG行为严重依赖于抑制性突触输入的假设，类似于许多假设

DESCRIPTION (provided by applicant): The long term goal of our research team is to understand how brain stem motor circuits that control life sustaining autonomous breathing patterns develop, mature and maintain rhythmic neural activity. It is also relevant to determine how these circuits respond to abnormal environments and stress. This project proposes to use a new experimental model system to explore the location(s), synaptic physiology, and plasticity of breathing-related central pattern generators (CPGs) in the isolated Zebra Finch brain stem during early development. The avian embryonic model is uniquely tractable for experimental manipulation and provides unparalleled access to central neuronal networks throughout prenatal development. We will use anatomical techniques, nerve cell activities, and pharmacology to test our hypotheses in the context of understanding normal breathing behaviors and breathing-related neuropathologies in which the modification or loss of brain stem structures that control normal rhythm and motor patterns can lead to increased morbidity and mortality in neonates and adults. Importantly, funds from this proposal will introduce students to Biomedically-based research at Idaho State University (ISU) using hands-on lab experiences and focused individual training in a variety of professional and scientific practices. We seek to address three key aspects associated with the field of developmental neurobiology and the control of breathing: 1. Identification of spatially separate respiratory-related brain stem CPGs. Aim 1 will test the role of the avian nucleus paraambiguus (PAm) and the retroambiguus (RAm) in the neurogenesis of automatic breathing rhythms. Historically, in vitro studies have focused on the inspiratory phase. Yet, the breathing cycle involves both inspiration and expiration. Since birds employ active inspiration and active expiration, even at rest, we hypothesize that avian embryos at the internal hatching stage (i.e., when continuous air-breathing begins) generate breathing rhythms with two independent yet coupled CPGs, similar to the situation in exercising humans when high levels of ventilatory drive is necessary. 2. Mechanisms of burst generation and pattern formation in the avian brain stem. Aim 2 will test the hypothesis that respiratory-related CPG behavior in birds is critically dependent on inhibitory synaptic input, similar to many network-based locomotor CPG circuits. Specifically, we hypothesize spontaneous rhythms will be critically dependent on chloride-mediated neurotransmission as a mechanism to control duty cycles for breathing pattern. As an alternate hypothesis, we will test the role of endogenous pacemaker mechanisms in the maintenance and shape of respiratory-related CPG output.3. Mechanisms of homeostatic/developmental plasticity in the breathing-related brain stem. Aim 3 will test how persistent embryonic manipulations of rhythmic electrical activity with and without manipulations of specific neurotransmitters may alter the developmental expression of CPG behavior as well as the phenotype of neurotransmitter systems that support breathing.