DISCHARGE PATTERNS OF MOTONEURONS

这项研究的长期目标是确定 介导GR的初级传入去极化(PAD)。我的肌肉和 猫脊髓中的皮肤纤维，更准确地定义 它们所属的反射路径以及脊柱上的影响 它们调节着它们的活动。我们将特别注意 确定是否有中介GR垫的中间神经元。I纤维属于 仅施加突触前动作的私人路径，或者如果它们是共享的 也通过在运动神经元中产生突触后抑制的通路。 I.-在麻醉的猫中，同时的细胞外记录将是 由中间核和背根中的中间神经元组成 腹根细丝，在后一种情况下使用蔗糖间隙 技术。尖峰触发的平均线将被用来增强任何背部 根和/或腹根电位被时间锁定到 神经元间活动。这将允许披露突触 中间神经元与传入纤维和/或运动神经元的联系。 对这些中间神经元应答模式的详细研究 还将进行节段和脊柱上的输入，以定义 它们所属的反射路径。将尝试记录 从细胞内垫中介导中间神经元，并向它们注射 马萝卜过氧化物酶的形态特征。 二.-我们之前的调查显示，有两个独立的 参与Ia垫的中间核中间神经元组 受到脑干相反作用的纤维。自那以后 我们用于对GR进行分类的标准。伸肌I纤维 肌肉是基于刺激产生的垫子的图案 对于传入神经，这些研究现在将扩展到GR。I纤维来自 后二头肌-半腱肌GR。IA和Ib 纤维则不那么模棱两可。这些调查预计将提供 关于中间神经元功能组织的信息 它调节着GR的垫子。屈肌和伸肌的IA纤维。 三.-我们将研究平均、方差和相关性的变化 同时记录的单纤维Ia单突触EPSPS 运动神经元对在不同程度的激动剂和 对抗肌肉。我们将特别注意可能出现的 两种情况下产生的EPSP的相关故障的存在性 运动神经元作为突触前终末传导阻断的证据。

The long term goals of this research are to identify the interneurons which mediate the primary afferent depolarization (PAD) of gr. I muscle and of cutaneous fibers in the cat spinal cord, and to define more precisely the reflex pathways to which they belong, as well as the supraspinal influences which modulate their activity. Particular attention will be given to determine if the interneurons mediating the PAD of gr. I fibers belong to private pathways exerting presynaptic actions only, or if they are shared also by pathways producing post-synaptic inhibition in motoneurons. I.- In the anesthetized cat, simultaneous extracellular recordings will be made from interneurons in the intermediate nucleus and from dorsal root and ventral root filaments, using in the latter case the sucrose gap technique. Spike triggered averages will be used to enhance any dorsal root and/or ventral root potentials which are time locked to the interneuronal activity. This will allow disclosure of the synaptic connections of the interneurons with afferent fibers and/or motoneurons. Detailed investigation of the responsee patterns of these interneurons to segmental and supraspinal inputs will be also made in order to define the reflex pathways to which they belong. Attempts will be made to record intracellularly from the PAD mediating interneurons and to inject them with horse-radish peroxidase for their morphological characterization. II.- Our previous investigations suggest that there are two independent sets of intermediate nucleus interneurons mediating the PAD of the Ia fibers which are subjected to opposite actions from the brain-stem. since the criteria which we have used to classify gr. I fibers of extensor muscles have been based on the patterns of the PAD produced by stimulation of afferent nerves, these studies will now be extended to gr. I fibers from the posterior biceps-semitendinosus where classification of gr. Ia and Ib fibers is less equivocal. These investigations are expected to provide information pertaining the functional organization of the interneurons which mediate the PAD of the gr. Ia fibers of flexors and extensors. III.- We will study the changes in the mean, variance and correlation of the single fiber Ia monosynaptic EPSPs recorded simultaneously from motoneuron pairs during varying amounts of stretch of agonist and antagonist muscles. Particular attention will be given to the possible existence of correlated failures of the EPSPs generated in the two motoneurons as evidence for conduction blockade in presynaptic terminals.