FUNCTIONAL ORGANIZATION AND CONTROL OF HUMAN MASSETERS

动物研究提供了肌肉纤维的详细分析 类型，肌肉组织，神经解剖学途径和机制， 在咀嚼等动作中对颌部肌肉的神经控制。 数据 这些研究有助于形成目前的解释 神经生物学和口腔运动功能的控制。 然而，最近的数据 提供了一个更复杂的解剖和功能的证据， 组织的颌骨肌肉在动物，但类似的系统研究 还没有在人类受试者中进行过。 随着新的 技术，现在可以对肌肉进行非侵入性成像， 检查解剖组织的细节，同时 获取多部位记录以分析局部肌肉活动，或 功能性“隔间”。 必须了解 正常人的解剖组织和功能控制的基础 在试图评估异常肌肉之前， 涉及疼痛的情况。 因此，本提案将审查以下基本原则： 的解剖学基础、功能组织和机制 控制人类的咬肌 一个合乎逻辑的进展将是 接着首先检查咬肌内部解剖结构， 在尸体和磁共振中识别其结构分区 人类的图像，然后研究功能性神经肌肉， 通过多部位EMG记录的肌肉的隔室。 后一 实验组包括（1）绘制运动单元区域， 募集顺序和运动单位特征;（2）调查 传入对运动单位的募集和活动的影响;以及 (3)比较几种皮肤传入神经的抑制作用， 口腔内部位对运动单位活动的影响 经过全面评估， 正常人咬肌的功能组织 没有痛苦，我们将检查相同的主题， 实验诱导的面部疼痛，并测试一个模型， 解释慢性疼痛患者的运动活动变化。

Animal studies have provided a detailed analysis of muscle fiber types, muscle organization, neuroanatomical pathways and mechanisms of neural control of jaw muscles during such acts as mastication. The data from these studies have helped form the current explanations of the neurobiology and control of oral-motor function. However, recent data have provided evidence of a more complex anatomical and functional organization of the jaw muscles in animals but similar systematic studies have not been performed in human subjects. With the advent of new technologies, it is now possible to non-invasively image muscles to examine the detail of the anatomical organization and to simultaneously acquire multi-site recordings to analyze regional muscle activity or functional "compartments". It is imperative to understand the fundamentals of anatomical organization and functional control of normal human subjects before attempting to evaluate the abnormal muscular conditions which involve pain. Therefore, this proposal will examine the basic fundamentals of the anatomical substrate, functional organization and mechanisms of control of the human masseter muscle. A logical progression will be followed by first examining the masseter internal anatomical architecture to identify its structural partitions in cadavers and magnetic resonance images of humans, and then studying the functional neuromuscular compartments of the muscle by multi-site EMG recordings. This latter group of experiments include (1) mapping motor unit territory, recruitment order and motor unit characteristics; (2) investigating the effects of afferents on the recruitment and activity of motor units; and (3) comparing the inhibitory effects of cutaneous afferents from several intraoral sites on motor unit activity. After a thorough evaluation of the functional organization of the masseter muscle in normal subjects without pain, we will examine the same subjects with experimentally-induced facial pain and test a model that attempts to explain the changes in motor activity described in chronic pain patients.