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，因此对于体内平衡至关重要。来自 8 种不同肌肉的纤维插入哺乳动物的舌头并控制其运动、形状和硬度，但舌头肌肉运动单位的控制在很大程度上被忽视了。我们的目标是通过解决以下问题来探索中枢神经系统如何控制涉及多个肌肉作用于单个机械结构的模式化行为（由呼吸中枢模式发生器 CPG 控制的驱动）：1）运动神经元驱动舌头突出和牵开肌接收显着的共同突触输入，尽管它们对舌头具有相反的机械作用，这表明激动剂-拮抗剂共同激活控制舌头僵硬； 2) 舌头和“主要”吸气肌（膈肌、肋间肌）的呼吸相关输入来自独立来源； 3）模型预测，随着细胞突触输入的增加，运动单位尖峰序列变得更加可变。当兴奋性突触输入叠加在呼吸 CPG 发出的基础输入上时，可以通过测量尖峰序列变异性的变化来测试这一点； 4) 支配舌肌进行呼吸相关活动的运动单位分为 2 个功能群；那些在肌肉驱动力增加时对代码进行评分的人，以及那些不这样做的人。我们认为，尽管突触输入增加，但不对代码进行评级的运动单元的放电率仍会饱和；我们将检验这个假设； 5) 肌肉内的各个运动单位至少包括 4 个特定任务子群（吸气、呼气、紧张和呼气-吸气单位），并且给定单位的任务特异性取决于其收缩特性。实验将在麻醉的、自主呼吸的成年老鼠身上进行。使用的技术包括单运动单元电生理学、互相关分析和通气输出测量。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库。