The role of pFRG neurons in the respiratory network.

描述(申请人提供)：呼吸是一种强健和适应性的行为，其复杂性往往被忽视，因为它的持续存在。最近的研究表明，呼吸是由脑干中两个不同的节奏中心产生的。一种假设是，每个中枢负责呼吸的一个特定方面：一个中枢负责吸气(PreBotzinger Complex，PreBotzinger Complex)，另一个中枢负责主动呼气(副面部呼吸组，pFRG)。到目前为止，这两个中心之间的联系以及pFRG的确切作用尚不清楚。为了开始了解前BotC和pFRG之间的相互作用，我们将通过将不同颜色的染料注入不同的中心并进行轨迹追踪实验(AimlA)来表征两个中心之间的直接和间接解剖连接。我们将获得每个中枢单个神经元的电记录，并重建其形态(AimlB)。因此，我们将更清楚地了解这两个中心是如何连接的，包括识别延髓中的间接联系。对于每个中枢的单个神经元，我们将开始将放电模式与特定的解剖投射联系起来。这两组实验都将增加我们对呼吸神经回路组织的理解。为了确定每个节律中心在呼吸中的作用，我们将使用药物选择性和可逆地加速或减慢一个节律中心(pFRG或preBotC)，同时持续监测不同脊神经上与呼吸相关的运动活动(Aim2A)。使用药物，我们将可逆地使pFRG沉默，并表征呼吸节奏和模式的变化。与这些实验相关，我们将进一步量化具有pFRG/RTN病理(Aim2B)的转基因小鼠(Krox20-/-)的呼吸节律和模式。如果我们的跑步假设是正确的，那么没有功能性pFRG的小鼠的呼吸节律应该与pFRG可逆性沉默的大鼠的呼吸节律相似。最后，当一个神经元受到刺激时，我们将光学监测呼吸中心，以观察中心内和中心之间的连通性(Aim3)。与公共健康相关：在人类中，呼吸是生命所必需的，需要神经系统产生可靠而有力的节奏。这项拟议的研究旨在了解两个有节奏的脑干中心是如何联系在一起的，以及它们是如何相互作用来产生呼吸的。这些信息可以帮助开发合理的中枢性睡眠障碍疗法，并将提高我们对参与呼吸节奏的神经系统的理解。

DESCRIPTION (provided by applicant): Breathing is a robust and adaptive behavior, and its complexity is often overlooked because of its constant presence. Recent work suggests that breathing is produced by two distinct rhythmic centers in the brainstem. One hypothesis is that each center is responsible for a specific aspect of breathing: one center is responsible for inspiration (preBotzinger complex, preBotC), the other is responsible for active expiration (parafacial respiratory group, pFRG). To date, the connectivity between these two centers is unclear as is the precise role of the pFRG. To begin to understand the interplay between the preBotC and the pFRG, we will characterize the direct and indirect anatomical connectivity between the two centers by injecting dyes of different colors into the different centers and performing tract-tracing experiments (AimlA). We will obtain electrical recordings from single neurons in each center and reconstruct their morphology (AimlB). We will thus gain a clearer picture of how the two centers are connected, including the identification of indirect connections in the medulla. For individual neurons in each center we will begin to link firing patterns to specific anatomical projections. Both sets of experiments will increase our understanding of the organization of the neural circuit for breathing. To determine the role of each rhythmic center in breathing, we will use drugs to selectively and reversibly speed up or slow down one rhythmic center (pFRG or preBotC) while continuously monitoring breathing-related motor activity on distinct spinal nerves (Aim2A). Using drugs, we will reversibly silence the pFRG and characterize changes in the breathing rhythm and pattern. Related to these experiments, we will provide further quantification of the breathing rhythm and pattern in transgenic mice (Krox20-/-) that have pFRG/RTN pathology (Aim2B). If our running hypothesis is correct, the mice without a functional pFRG should have breathing rhythms that are similar to those observed in rats where the pFRG is reversibly silenced. Last, we will optically monitor the breathing centers when one neuron is stimulated to look at within center and between center connectivity (Aim3). Public health relevance: ln humans, breathing is essential to life and requires that the nervous system generate a reliable and robust rhythm. The proposed study aims to understand how two rhythmic brainstem centers are connected and how they interact to produce breathing. This information can aid in the development of rational therapeutics for central sleep disorders and will improve our understanding of the neural systems that are involved in the breathing rhythm.