Quantitative model of jaw proprioception during active movements

主动运动过程中下颌本体感觉的定量模型

• 批准号: 10750622
• 负责人: Jeong Jun Kim
• 金额: $ 5.35万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-11 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10750622
• 关键词: Affect; Anesthesia procedures; Behavior; Biomechanics; Cell Nucleus; Code; Complex; Coupling; Dedications; Electrophysiology (science); Elements; Feedback; Fiber; Gamma Motor Neurons; Goals; Jaw; Length; Masticatory muscles; Mechanics; Modality; Modeling; Monitor; Motion; Motor; Motor Cortex; Motor output; Movement; Mus; Muscle; Muscle Spindles; Musculoskeletal; Nature; Neurons; Noise; Orofacial Pain; Parents; Pattern; Process; Property; Proprioception; Proprioceptor; Regulation; Rodent; Sensory; Signal Transduction; Source; Stretching; System; Temporomandibular Joint Disorders; Testing; Training; Trigeminal Nuclei; Trigeminal System; Work; awake; body position; body sense; computer framework; control theory; craniofacial structure; density; design; flexibility; hindbrain; in vivo; jaw movement; kinematics; mechanical force; mechanical signal; motor control; nerve supply; neural; neural model; neuromechanism; novel; optogenetics; orofacial; receptor; sensor; sensorimotor system; tool

PROJECT SUMMARY Proprioception is an indispensable sense of the body’s position and movement in space. Fine motor control depends on proprioceptors to monitor the mechanical consequences of motor actions. In particular, muscle spindles are a class of primary proprioceptors that detect muscle length and stretch at the intrafusal fibers. The signals generated by muscle spindles are complex with dynamical regulation of intrafusal fiber lengths via γ motor neuron (fusimotor) activity. The interaction between feedforward mechanical signals at the muscle spindle and descending motor commands at the parent muscle, especially in the context of naturalistic movements, remains poorly understood. Opposing views disagree on whether muscle spindles passively sense muscle length/stretch or actively process biomechanical signals based on motor commands to the muscle. Using the unique advantages of rodent jaw proprioceptors in the hindbrain mesencephalic trigeminal (MeV) nucleus, I will test the hypothesis that motor commands flexibly tune jaw muscle spindle coding in a context-dependent manner. With experimental access to many levels of the jaw sensorimotor circuit, I will determine how feedforward mechanical signals and descending motor commands interact at the primary proprioceptors. Aim 1 will find the relationship between motor unit activity in jaw muscles and corresponding muscle spindle activity during passive and active movements. Aim 2 will record muscle spindle activity with (a) external loads on the jaw and (b) optogenetic decoupling of motor drives from muscle-driven motion. Aim 3 will provide an overarching framework to model the jaw system as a feedback control loop. The proposed project investigates proprioceptive feedback in craniofacial structures, electrophysiological mechanisms for controlling jaw function, and quantitative models of the neural controller and muscles of the jaw. The immense training potential in this project lies in the application of novel in vivo electrophysiology tools, well-designed use of optogenetics, and quantitative modeling rooted in control theory. The proposed work has important implications in elucidating orofacial proprioception at the primary receptors and understanding temporomandibular disorders and orofacial pain involving maladaptive control of the jaw.

项目摘要 本体感觉是人体在空间中的位置和运动的一种不可或缺的感觉。精细运动控制 依赖于本体感受器来监测运动动作的机械后果。尤其是肌肉 梭是一类主要的本体感受器，其检测梭内纤维处的肌肉长度和拉伸。的 由肌梭产生的信号是复杂的，通过γ动态调节梭内纤维长度 运动神经元（fusimotor）活动。肌梭前馈机械信号之间的相互作用 和下行运动指令在父母的肌肉，特别是在自然运动的背景下， 仍然知之甚少。关于肌梭是否被动感知肌肉，对立的观点意见不一 长度/拉伸或基于对肌肉的运动命令主动处理生物力学信号。使用 独特的优势，啮齿动物下颌本体感受器在后脑中脑三叉神经（MeV）核，我将 测试的假设，电机命令灵活地调整下颌肌梭编码的上下文相关的方式。 通过对下颌感觉运动回路的多个层次的实验，我将确定前馈 机械信号和下行运动指令在初级本体感受器处相互作用。目标1将找到 被动时颌肌运动单位活动与相应肌梭活动的关系 积极的运动。目标2将记录肌梭活动，（a）下颌上的外部载荷和（B） 运动驱动与肌肉驱动运动的光遗传学解耦。目标3将提供一个总体框架 将颌系统建模为反馈控制回路。拟议的项目调查本体感觉反馈 在颅面结构中，控制颌功能的电生理机制和定量模型 神经控制器和下巴肌肉的连接。该项目的巨大培训潜力在于应用 新颖的体内电生理学工具，精心设计的光遗传学使用，以及植根于 控制理论这项工作对阐明口面部的本体感觉具有重要意义。 初级受体和理解颞下颌关节紊乱病和口面疼痛涉及适应不良 控制下巴。