Motor unit diversity in horizontal eye movement control

水平眼球运动控制中运动单位的多样性

• 批准号: 8900285
• 负责人: Paul Douglas Gamlin
• 金额: $ 49.79万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8900285
• 关键词: Address; Anatomy; Animals; Brain; Characteristics; Contact Lenses; Data; Development; Diagnostic radiologic examination; Diplopia; Electric Stimulation; Electrodes; Eye; Eye Movements; Face; Fatigue; Fiber; Generations; Health; Histology; Image; Implant; Individual; Isometric Exercise; Knowledge; Lateral; Lead; Lesion; Location; Macaca; Macaca mulatta; Magnetic Resonance Imaging; Measurement; Measures; Medial; Methods; Modeling; Monkeys; Motor; Motor Neurons; Movement; Muscle; Muscle Fibers; Nerve; Neurons; Ocular Motility Disorders; Operative Surgical Procedures; Pharmaceutical Preparations; Phase; Physiological; Physiology; Plants; Positioning Attribute; Primates; Procedures; Property; Protein Isoforms; Recruitment Activity; Reporting; Research Personnel; Retinal; Role; Saccades; Signal Transduction; Site; Smooth Pursuit; Specificity; Speed; Staging; Strabismus; Suction; System; Techniques; Tendon structure; Testing; Time; Transducers; Vision; design; gaze; instrument; interest; motor control; nerve supply; neuromuscular; neuromuscular system; neuroregulation; nonhuman primate; novel; oculomotor; orbit muscle; relating to nervous system

DESCRIPTION (provided by applicant): The oculomotor control system of foveate animals such as primates faces very diverse demands depending on the eye movement task. During some periods of time, the brain must precisely control the extraocular muscles so the eyes steadily fixate and stabilize the retinal image; during other periods, it must control the extraocular muscles to move the eyes rapidly from one position to another (saccades), or track objects of interest at widely differing speeds (smooth pursuit), or precisely change the viewing angle of the two eyes (vergence). It is currently assumed that these eye movements are produced through common pools of motor units (a "motor unit" is a motor neuron and its muscle fibers), recruited irrespective of task. But there is clear anatomic and histological evidence of motor unit diversity with physiological evidence of differential inputs from the oculomotor subsystems. Also, by directly measuring eye muscle forces using muscle force transducers (MFTs) and finding that they could not be predicted from neural innervation, we recently demonstrated that the simple concept of a final common motor path is incorrect ("missing force paradox"), and that this notion likely has impaired our understanding of the neuromuscular control of eye movements. In non-human primates, we propose to investigate how motor units with distinct characteristics and locations are recruited differentially for different horizontal ee motor tasks (saccades, smooth pursuit, and vergence) and task phases (phasic and tonic). We will identify lateral and medial rectus motoneurons using antidromic activation and spike-triggered averaging of electromyograms (STA-EMG), and measure motor unit functional properties using spike-triggered averaging of the muscle force transducer signal (STA-MFT), a new method we have recently validated. We will precisely localize motoneurons with X-ray images registered to MRI and histology, and fully characterize motor unit activity during these horizontal eye movements. Better understanding of eye motor control should lead to better treatment of eye movement disorders, such as strabismus. Drugs that modify eye muscle properties, elsewhere under development, show promise as simple, inexpensive office procedures able to effect corrections not possible with strabismus surgery. Our STA- MFT technique would be suitable to study the fiber type specific functionality of pharmacologically-modified motor units in alert animals. Relevance The novel techniques used in this proposal will allow us, for the first time, to study long-overlooked task specificities in the neuromuscular systems that stabilize and move our eyes for effective vision. These studies should result in more effective and less costly treatments for strabismus and other eye movement disorders that are of a neuromuscular origin.

描述（由申请人提供）：诸如灵长类动物之类的动物的动眼控制系统，根据眼动任务的不同需求。在某些时期，大脑必须精确控制眼外肌肉，使眼睛稳步固定并稳定视网膜图像。在其他时期，它必须控制眼外肌肉，以将眼睛从一个位置迅速移动到另一个位置（扫视），或以广泛不同的速度（平滑追击）或精确改变两只眼睛的视角（vergence）。目前假定这些眼睛运动是通过通用电动机单元（一个“运动单元”是运动神经元及其肌肉纤维）产生的，无论任务如何，都会招募。但是，有明显的解剖学和组织学证据表明运动单位多样性，具有眼动子亚系统差异输入的生理证据。同样，通过使用肌肉力传感器（MFT）直接测量眼部肌肉力，并发现无法通过神经神经支配预测它们，我们最近证明了最终公共电动路径的简单概念是不正确的（“失踪力悖论”），并且这一概念可能损害了我们对眼睛动作神经肌肉控制的理解。 在非人类灵长类动物中，我们建议研究如何将具有不同特征和位置的运动单元差异招募，以差异化，以鉴定用于不同的水平EE运动任务（扫视，平稳的追求和Gergence）和任务阶段（Phasic and Tonic）。我们将使用抗体激活来鉴定侧向和内侧直肌运动神经元，并通过尖峰触发肌电图的平均（STA-EMG），并使用尖峰触发的平均肌肉力传感器信号（STA-MFT）测量运动单位功能性能，我们最近已验证了一种新方法。我们将精确地将运动神经元定位在MRI和组织学上注册的X射线图像，并在这些水平眼运动过程中充分表征运动单位活动。 更好地理解眼运动控制应可以更好地治疗眼动障碍，例如斜视。改变眼部肌肉特性的药物在开发的其他地方表现出了有望，因为简单，廉价的办公手术能够通过斜视手术进行校正。我们的STA-MFT技术适合研究警报动物中药理修饰的运动单元的纤维类型特异性功能。相关性，该提案中使用的新技术将使我们首先研究神经肌肉系统中长期忽略的任务特异性，这些任务稳定并动摇了我们的眼睛以获得有效的视力。这些研究应导致对神经肌肉起源的斜视和其他眼部运动障碍的更有效和成本更低的治疗方法。