BRAIN STEM INTEGRATION OF CHEMORECEPTOR ACTIVITY

其目的是表征颅运动神经的活动 其支配上气道肌肉和支配肌肉的脊神经 胸壁和横膈膜 这些特征很重要 由于上呼吸道的开放需要在 这些颅神经和脊神经活动。 研究将关注肺反射机制。 的影响 肺牵张感受器的时相性和强直性放电将 接受检查。 紧张性放电被假设为是一个主要的决定因素 在呼气过程中的脑运动神经元活动。 此外，脑干呼吸神经元的兴奋性水平是 受肺牵张感受器紧张性放电的影响。这 兴奋性水平决定运动神经元对周围神经元的反应 化学感受器刺激缺氧。 关于颅运动神经元， 它们的活动受到以下阶段活动的“历史”的影响： 肺牵张感受器;这一历史将被描述。 肺牵张感受器放电的另一个方面， 吸气活动，是膈神经运动神经元的连续决定因素 活动 膈神经的活动也会受到 肺牵张感受器 表达式的条件 将定义促进或抑制。 该定义将允许 对I-α和I-β组的作用进行了严格的评估， 延髓呼吸神经元 他们的放电模式是假设的 以说明膈神经活动的抑制和促进， 肺牵张感受器的放电。 因此，I-α和I-β神经元 被假设为代表一个连续体。

The objective is to characterize the activities of cranial motor nerves which innervate upper airway muscles and spinal nerves innervating muscles of the chest wall and diaphragm. These characterizations are important since patency of the upper airway requires an appropriate balance between these cranial and spinal nerve activities. Studies will be concerned with pulmonary reflex mechanisms. The influence of both the phasic and tonic discharge of pulmonary stretch receptors will be examined. The tonic discharge is hypothesized to be a major determinant of respiratory-modulated cranial motoneuronal activity during expiration. Moreover, the level of excitability of brainstem respiratory neurons is influenced by the tonic discharge of pulmonary stretch receptors. This level of excitability determines motoneuronal responses to peripheral chemoreceptor stimulation in hypoxia. Concerning the cranial motoneurons, their activity is influenced by the "history" of phasic activity of pulmonary stretch receptors; this history will be characterized. Another aspect of pulmonary stretch receptor discharge, its facilitation of inspiratory activity, is a continuous determinant of phrenic motoneuronal activity. Phrenic activity can also be inhibited by the discharge of pulmonary stretch receptors. Conditions for the expression of a new facilitation or inhibition will be defined. This definition will allow for a critical evaluation of the roles of I-alpha and I-beta groups of medullary respiratory neurons. Their discharge patterns are hypothesized to underlie the inhibition and facilitation of phrenic activity by the discharge of pulmonary stretch receptors. Thus, I-alpha and I-beta neurons are hypothesized to represent a continuum.