BRAINSTEM RESPIRATORY NEURON INTERACTIONS

这项研究的目标是定义脑干神经网络 为运动神经元提供中枢呼吸驱动， 呼吸肌肉，并确定如何通过颈动脉网络调制 压力感受器和化学感受器。 计划中的实验涉及五个 假设 1. 多个网络机制的层次结构有助于 呼吸的每个阶段的发展和终止。 分布式 系统包含多个本地网络，每个网络足以生成 有节奏的活动，但比整体适应性差。 2. 颈动脉压力感受器活动对呼吸驱动的调节 由中线和外侧髓和脑桥神经网络介导 平行操作。 3. 孤束核的神经元分布于周围 化学感受器信息同时传递到中缝中线，延髓外侧， 和脑桥呼吸神经元通过发散的平行投射。 延长的外周化学感受器活动重组了功能性的 这些脑干区域之间的连接， 驱动膈运动神经元。 同步活动的变化 在平均放电中没有相应变化的神经组件构成 一种调节呼吸活动的机制。 4. 内在脑干机制与肺牵张感受器反馈 共同提供信号以产生呼吸“门控”， 压力感受器和化学感受器反射作用。 5. 延髓-脑桥神经元投射的“多层”拓扑结构 作为空间分布的冗余容错呼吸系统， 协调机制。 实验将在麻醉或人工去大脑的情况下进行 通风猫 肺牵张感受器和颈动脉压力-和 化学感受器将被选择性地刺激以干扰呼吸 相关的神经活动，而多达30个呼吸神经元在五个 同时监测不同的脑干区域。 这许多- 将使用神经元记录和先进的定量分析方法 检测和评估功能连接和协作 交互. 这些结果将定义神经网络所需的参数。 网络模拟旨在确定模型是否来自 动物实验是合理的，足以产生观察到的 网络行为 这项工作将有助于我们了解 控制呼吸和两个更广泛的问题：（1）大脑如何 并行处理信息吗 (2)大脑是如何重组 产生适应性反应？

The goal of the proposed research is to define the brainstem neural network that provides the central respiratory drive to the motor neurons and muscles of breathing and determine how the network is modulated by carotid baroreceptors and chemoreceptors. Planned experiments address five hypotheses. 1. A hierarchy of multiple network mechanisms contributes to both the development and termination of each phase of breathing. A distributed system incorporates multiple local networks, each sufficient to generate rhythmic activity, but with less adaptability than the whole. 2. Modulation of respiratory drive by carotid baroreceptor activity is mediated by midline and lateral medullary and pontine neural networks operating a parallel. 3. Neurons of the nucleus of the solitary tract distribute peripheral chemoreceptor information concurrently to midline raphe, lateral medullary, and pontine respiratory neurons via divergent parallel projections. Prolonged peripheral chemoreceptor activity reorganizes the functional connectivity among these brainstem regions and potentiates the respiratory drive to phrenic motoneurons. Changes in the synchronous activity of neural assemblies without corresponding changes in mean firing constitutes one mechanism for modulating respiratory activity. 4. Intrinsic brainstem mechanisms and pulmonary stretch receptor feedback jointly provide signals to generate respiratory "gating" of the baroreceptor and chemoreceptor reflex actions. 5. The "multi-layered" topology of medullary-pontine neuron projections serves as a spatially distributed redundant fault tolerant respiratory coordinating mechanism. Experiments will be performed with anesthetized or decerebrate artificially ventilated cats. Pulmonary stretch receptors and carotid baro- and chemoreceptors will be selectively stimulated to perturb respiratory related neural activity while as many as 30 respiratory neurons in five different brainstem regions are monitored simultaneously. These many- neuron recordings and advanced quantitative analytical methods will be used to detect and evaluate functional connectivity and cooperative interactions. These results will define parameters required for neural network simulations designed to establish whether models derived from the animal experiments are plausible and sufficient to generate observed network behavior. This work will contribute to our understanding of the control of breathing and two broader questions: (1) How does the brain process information in parallel? (2) How does the brain reorganize to produce adaptive responses?