BRAIN STEM INTEGRATION OF CHEMORECEPTOR ACTIVITY

目的是描述颅运动神经的活动特征。 它们支配上呼吸道肌肉和支配肌肉的脊神经 胸壁和横隔膜。这些特征很重要 由于上呼吸道通畅需要在以下方面取得适当的平衡 这些脑神经和脊神经活动。 研究将关注肺反射机制。影响 肺牵张感受器的时相和紧张性放电 接受检查。紧张性放电被认为是一个主要决定因素。 呼气时呼吸调节的头颅运动神经元活动。 此外，脑干呼吸神经元的兴奋性水平是 受肺牵张感受器张力性放电的影响。这 兴奋性水平决定运动神经元对外周的反应 低氧条件下的化学感受器刺激。关于脑运动神经元， 它们的活动受其阶段性活动的“历史”的影响 肺伸展感受器；这一病史将被描述。 肺牵张感受器放电的另一个方面，它的易化 吸气活动是膈运动神经元的连续决定因素 活动。膈神经活动也可通过放电来抑制 肺伸展感受器。表达新的 将定义促进或抑制。这一定义将允许 对I-α和I-β组作用的批判性评估 延髓呼吸神经元。它们的放电模式是假想的 为抑制和促进膈神经活动奠定基础。 肺伸展感受器放电。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.