Understanding neuromusculoskeletal interactions underlying biomechanics and control of the human hand

灵巧的手功能是人类身份的一个决定性特征。在几乎所有的日常生活活动中，从早上穿衣服到晚上准备晚餐，手都是至关重要的。完全对生的拇指对手部功能尤其重要，它可以通过抓握或捏捏来与物体和工具进行交互。虽然手的多功能性是现代人类智慧的中心主题，但其复杂的解剖结构挑战了我们对机械功能和神经肌肉控制的理解。手工密集型任务的成功执行最终依赖于神经生理（如感觉和运动神经）和生物力学装置（如肌肉和肌腱）的无缝相互作用。然而，研究这些系统如何相互作用以保持手的功能是非常必要的，特别是在需要在线控制姿势和握力的复杂职业任务中。我的研究将使用一种创新的，跨学科的方法来研究手部生物力学和神经肌肉控制。本研究将分为三个主题：(1)确定机械相互作用；(2)通过实验操纵感觉运动通路，阐明生物力学与神经生理学之间的联系；(3)开发能够表示手部神经肌肉骨骼耦合的计算机模型。******第一个主题将研究手的肌肉骨骼结构之间的机械相互关系。参与者将进行与职业相关的手工活动。测量将包括使用力传感器的握力，通过动作捕捉的关节角度，以及来自细线肌电图的肌肉活动，重点是外部（大）和内部（小）手部肌肉之间的负载分担。进一步的研究将使用电刺激来引起拇指肌肉收缩。超声将评估腕管（腕）的大小和形状以及穿过腕的解剖结构的机械性能的同时变化。第二个主题将集中在短期内神经生理机制改变时的感觉运动整合和适应。具体来说，将在对手腕施加压缩力之前、期间和之后评估手的生物力学功能。本主题的研究还将通过实验操纵视觉反馈来确定感觉输入对生物力学功能和神经肌肉控制的综合效应。第三个主题将开发一个手的计算机模型，以结合从第一个和第二个研究主题收集的数据。这项创新研究将评估整个生物系统的冗余，为工业工程和人体工程学（如工具设计）等几个重要领域提供信息，以提高工作绩效和效率。

Dexterous hand function is a defining feature of the human identity. The hand is vitally important in nearly all activities of daily living, from getting dressed in the morning to preparing dinner in the evening. The fully opposable thumb is especially crucial to hand function, enabling interaction with objects and tools via gripping or pinching. While the hand's versatility is a central theme in modern human ingenuity, its complex anatomy challenges our understanding of mechanical function and neuromuscular control. Successful performance of a hand-intensive task ultimately relies on the seamless interaction of neurophysiological (e.g. sensory and motor nerves) and biomechanical apparatus (e.g. muscles and tendons). However, there is an immense need to investigate how these systems interact with each other to preserve hand function, especially during complex occupational tasks that require online control of postures and grip forces. My research will use an innovative, inter-disciplinary approach to investigate hand biomechanics and neuromuscular control. This research will be organized in three themes: (1) Determining mechanical interactions; (2) Elucidating links between biomechanics and neurophysiology by experimentally manipulating sensorimotor pathways; (3) Developing a computer model capable of representing neuromusculoskeletal coupling within the hand.******The first theme will investigate mechanical inter-relationships between musculoskeletal structures of the hand. Participants will perform occupationally relevant hand activities. Measurements will include grip forces using a force sensor, joint angles via motion capture, and muscle activity from fine-wire EMG, with a focus on load sharing between the extrinsic (large) and intrinsic (small) hand muscles. Additional studies will use electrical stimulation to elicit thumb muscle contractions. Ultrasound will assess concurrent changes in the size and shape of the carpal tunnel (wrist) as well as mechanical properties of the anatomical structures passing through the wrist. The second theme will focus on sensorimotor integration and adaptation when neurophysiological mechanisms are altered for a short time. Specifically, biomechanical hand function will be assessed before, during, and after a compressive force is applied to the wrist. Studies in this theme will also experimentally manipulate visual feedback to determine the integrated effects of sensory input on biomechanical function and neuromuscular control. The third theme will develop a computer model of the hand to combine data gathered from the first and second research themes. This innovative research will assess redundancies across biological systems, informing several important areas such as industrial engineering and ergonomics (e.g. tool design) to improve work performance and efficiency.