FATIGUE OF SEGMENTAL MOTOR MECHANISMS

描述(改编自申请人的摘要)：很有说服力 在各种正常和病理生理条件下， 肌肉疲劳的表现可归因于 从中枢神经系统(CNS)的前脑到收缩 活跃肌肉中的单纤维机械。关于神经的知识 然而，疲劳的神经肌肉方面远没有 这是关于纯粹的肌肉机制。这种不平衡可以归因于 很大程度上是因为需要获得更多关于潜在机制的信息 在整个CNS中重复激发INS，在整个CNS内重复激发MN 大脑和脊髓。 在这项提议中，重点首先放在原子弹的重复发射特性上 脊髓运动神经元(MN)和腹角中间神经元(程度较轻) (INS)。结果表明，通过获得关于两个关键射速的更多信息， 特性、激励电流(I)-尖峰频率(F)关系 MNS和MNS的尖峰频率适应(即随时间的f下降) 和INS，应该可以提供对基本脊椎的洞察 与肌肉疲劳相关的机制。接下来，我们将展示如何 关于MN发射模式的信息对部队发展具有重要意义 运动单位穿着新鲜疲惫的肌肉。这涉及到考虑 I-F关系、尖峰频率之间的关系 MNS的适应性，激活频率(F)-力(F)的关系 由MNS提供的电机单元，以及由电机单元开发的F 随着时间的推移。 总体方法有两个具体目标。首先，探索脊椎 MNS固有I-f关系的神经调节作用及其机制 脊髓MN和INS的尖峰频率适应，接下来，使用MN 结果的组成部分，以探索I-F关系和F下降 运动单位在新鲜和疲劳肌肉中的时间。 其目的是，这些研究将有助于提供有关 肌肉疲劳的细胞神经生物学，因此，有助于 这项研究的未来临床方法必须具备的科学基础 肌肉疲劳的症状。临床领域，如运动控制整形外科， 运动控制康复、功能性电刺激和运动 假肢需要一个基础，该基础包括大量的 基础神经科学，特别是更深层次的 对脊髓INS和MNS重复激发特性的理解 在新鲜的、疲惫的和病理生理的情况下转化为运动 各州。

DESCRIPTION (Adapted from the Applicant's Abstract): It is well established that in a variety of normal and pathophysiological conditions, the manifestation of muscle fatigue is attributable to mechanisms that extend from the forebrain of the central nervous system (CNS) to the contractile machinery of single fibers in active muscles. Knowledge about the neural and neuromuscular aspects of fatigue is, however, far less complete than that about purely muscular mechanisms. This imbalance is attributable largely to the need to gain more information on the mechanisms underlying the repetitive firing of INs throughout the entire CNS, and of MNs within the brain and spinal cord. In this proposal, the focus is first on the repetitive firing properties of spinal motoneurons (MNs) and, to lesser extent, ventral-horn interneurons (INs). It is shown that by gaining more information on two key firing-rate properties, the stimulus current (I) -spike-frequency (f) relationship of MNs and the spike frequency adaptation (i.e., the f drop over time) of MNs and INs, it should be possible to provide insight into fundamental spinal mechanisms associated with muscle fatigue. Next, it is shown how information on MN firing patterns has significance for the force developed by motor units in fresh and fatigued muscle. This involves consideration of the associations between the I-f relationship, the spike-frequency adaptation of MNs, the activation frequency (f) -force (F) relationship of the motor units supplied by the MNs, and the F development by motor units over time. The overall approach, has two specific aims. First, to explore the spinal neuromodulation of the intrinsic I-f relationship of MNs and the spike-frequency adaptation of spinal MNs and INs, and, next, to use the MN component of the results to explore the I-F relationship and F drop over time of motor units in fresh and fatigued muscle. The intent is that these studies will contribute fundamental information on the cellular neurobiology of muscle fatigue and as such, contribute to the scientific basis that must underlie future clinical approaches to the study of muscle fatigue. Clinical fields like motor-control orthopedics, motor-control rehabilitation, functional electrical stimulation and motor prosthetics require a foundation that includes a substantial component of fundamental neuroscience including, in particular, a far deeper understanding of how the repetitive firing properties of spinal INs and MNs are translated into movement in fresh, fatigued and pathophysiological states.