Control of finger movement and force for precision pinch

描述（由申请人提供）：多指操作需要众多肌肉之间的相互作用，以产生必要的指尖运动和力。手指（包括拇指）的肌肉被认为是多余的。长期以来，冗余一直被称为运动控制的核心问题，它也表明了某些肌肉丧失的健全性。到目前为止，我们的工作迫使并使我们能够系统地建立手指内肌肉之间的相互作用，以及紧握的手指，对肌肉功能障碍的抵抗力是如何下降的。每个假设和目标都解决了一个基本的，但目前尚未被理解的多指抓握的组成部分：手指缓慢运动和抓握平衡。为了验证每个假设，我们将应用并扩展我们的综合方法，将行为研究，尸体实验，数学分析和生物力学建模结合在两个互补的目标中。目的1：表征手指肌肉运动所需的机械相互作用；并将其健壮性量化为特定肌肉的损失。我们将重点关注肌腱张力如何影响拇指、食指和中指的缓慢运动的可行性。假设1：握力获取和释放缺乏冗余：缓慢的手指运动对某些肌肉的损失并不强健。目的2：表征多指抓握平衡中肌腱张力之间必要的相互作用；并将其健壮性量化为特定肌肉的损失。我们将重点关注个体肌肉的紧张如何影响两指和三指精确抓取的平衡（使用拇指尖：食指；和拇指：食指：中指）。我们还将探讨模拟信号相关噪声如何影响抓握平衡。主要假设IIa：静态抓握力缺乏冗余性：抓握平衡对某些肌肉的损失不是强健的。假设IIb：静态抓握力缺乏冗余：肌肉信号相关噪声进一步损害抓握平衡。本项目对多指抓握的理解将为理解灵巧操作在特定骨科/神经疾病、发育和衰老中的脆弱性（和康复）提供急需的神经力学基础。

DESCRIPTION (provided by applicant): Multifinger manipulation requires interactions among numerous muscles to produce the necessary fingertip motions and forces. The muscles of the fingers (including the thumb) are considered redundant. Redundancy, which has long been called the central problem of motor control, also suggests robustness to loss of some muscles. Our work to date compels and enables us to systematically establish how the interactions among muscles within a finger, and the fingers within a grasp, fail to be robust to muscle dysfunction. Each Hypothesis and Aim addresses the production of a fundamental, yet currently not understood, component of multifinger grasp: slow finger motions and grasp equilibrium. To test each Hypothesis we will apply and extend our integrative approach combining behavioral studies, cadaveric experiments, mathematical analysis, and biomechanical modeling in two complementary Aims. Aim 1: Characterize the necessary mechanical interactions among finger muscles for motion; and quantify their robustness to loss of specific muscles. We will focus on how tendon tensions affect the feasibility of slow motions of the thumb, index and middle fingers for grasp acquisition. Hypothesis I: Lack of redundancy for grasp acquisition and release: Slow finger motions are not robust to loss of some muscles. Aim 2: Characterize the necessary interactions among tendon tensions for multifinger grasp equilibrium; and quantify their robustness to loss of specific muscles. We will focus on how tensions from individual muscles affect the equilibrium of two- and three-finger precision grasps (using the tips of thumb:index; and thumb:index:middle). We will also explore how simulated signal-dependent noise affects grasp equilibrium. Primary Hypothesis IIa: Lack of redundancy for static grasp forces: Grasp equilibrium is not robust to loss of some muscles. Secondary Hypothesis Hypothesis IIb: Lack of redundancy for static grasp forces: Muscle Signal-Dependent Noise further compromises grasp equilibrium. The understanding gained about multifinger grasp in this project will provide the much-needed neuro-mechanical foundation to understand the vulnerability (and rehabilitation) of dexterous manipulation in specific orthopedic/neurologic diseases, development and aging. PUBLIC HEALTH RELEVANCE: Using our fingers to grasp and hold objects is necessary for us to perform most of our activities of daily living. However, because the anatomy of the hand is so complex, there is little known about how each muscle of the fingers contributes to grasping function. Our proposed project will combine anatomical studies, engineering science and clinical know-how to establish which muscles are most important, and therefore should be most protected, to improve the hand function of people suffering from the many disabilities of the hand.