Neuromuscular control of the mammalian tongue

哺乳动物舌头的神经肌肉控制

• 批准号: 7197647
• 负责人: Ralph Frank Fregosi
• 金额: $ 30.97万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7197647
• 关键词: Neuromuscular; control; mammalian; tongue

DESCRIPTION (provided by applicant): The tongue muscles participate in such diverse activities as breathing, swallowing, speech and mastication, and are thus critical for homeostasis. Fibers from 8 different muscles insert into the mammalian tongue and control its movement, shape and stiffness, but the control of tongue muscle motor units has been largely ignored. Our goal is to explore how the central nervous system controls a patterned behavior (drive controlled by the respiratory central pattern generator, CPG) that involves multiple muscles acting on a single mechanical structure, by addressing the following issues: 1) motoneurons driving tongue protrudor and retractor muscles receive significant common synaptic input even though they have opposite mechanical actions on the tongue, suggesting that agonist-antagonist co-activation controls tongue stiffness; 2) respiratory-related input to tongue and "primary" inspiratory muscles (diaphragm, intercostals) is derived from independent sources; 3) Models predict that motor unit spike trains become more variable as synaptic input to the cell is increased. This can be tested by measuring the change in spike train variability when excitatory synaptic input is superimposed on the underlying input emanating from the respiratory CPG; 4) Motor units innervating tongue muscles with respiratory related activity fall into 2 functional populations; those that rate code when drive to the muscle increases, and those that do not. We propose that the firing rate of motor units that do not rate code saturates despite increases in synaptic input; and we will test this hypothesis; 5) Individual motor units within a muscle comprise at least 4, task-specific sub-populations (inspiratory, expiratory, tonic and expiratory-inspiratory units), and the task specificity of a given unit depends on its contractile properties. Experiments will be done in anesthetized, spontaneously breathing adult rats. Techniques used include single motor unit electrophysiology, cross correlation analysis and the measurement of ventilatory output. The results of these experiments will contribute to the knowledge base needed to develop treatment strategies for obstructive sleep apnea, swallowing disorders, and oro-facial motor deficits.

描述（由申请人提供）：舌肌参与呼吸、吞咽、言语和咀嚼等多种活动，因此对体内平衡至关重要。来自8种不同肌肉的纤维插入哺乳动物舌头并控制其运动，形状和刚度，但舌头肌肉运动单元的控制在很大程度上被忽视。我们的目标是探索中枢神经系统如何控制一种模式化的行为（由呼吸中枢模式发生器CPG控制的驱动），其涉及作用于单个机械结构的多个肌肉，通过解决以下问题：1）驱动舌伸肌和缩肌的运动神经元接收显著的共同突触输入，即使它们在舌上具有相反的机械动作，这表明激动剂-拮抗剂共激活控制舌的僵硬; 2）舌和“初级”吸气肌（隔膜、肋间肌）的痉挛相关输入来源于独立的来源; 3）模型预测运动单位尖峰序列随着对细胞的突触输入的增加而变得更加可变。这可以通过测量当兴奋性突触输入叠加在从呼吸CPG发出的潜在输入上时尖峰序列可变性的变化来测试; 4）具有呼吸相关活动的支配舌肌的运动单元分为2个功能群体;当驱动肌肉增加时速率编码的那些，以及不速率编码的那些。我们建议，发射率的运动单位，不率代码饱和，尽管增加突触输入，我们将测试这一假设; 5）肌肉内的单个运动单位包括至少4个，任务特定的亚群（吸气，呼气，紧张和呼气-吸气单位），和一个给定的单位的任务特异性取决于其收缩性能。实验将在麻醉的自主呼吸成年大鼠中进行。所使用的技术包括单运动单位电生理学，互相关分析和测量的解释输出。这些实验的结果将有助于开发阻塞性睡眠呼吸暂停，吞咽障碍和口面部运动缺陷的治疗策略所需的知识基础。