Analysis of Neural control mechanism of precise hand movement (control of force,position and compliance)

本研究的目的是探讨参与手部自主精确运动的神经机制，即控制手部的位置、力和顺应性（机械阻抗）。所得结果总结如下。(1)建立了人体骨骼肌力学化学系数的估计方法。(2)计算拇指屈肌和伸肌的粘弹性系数。(3)粘弹性系数随自律性等距收缩力的增大呈线性变化。(4)利用数学模型估计了拇指位置和力控制中拉伸反射和机械阻抗的动态特性。(5)当产生较大的肌力或控制不稳定负载的位置时，拉伸反射增益和机械阻抗增强。(6)上臂各个关节的角度和施加在纸上的力在人类写信运动中被测量。利用该模型分析了中枢神经系统对书信书写的控制机制。

The purpose of the present study is to investigate neural mechanisms involved in the voluntary precise hand movement, i.e., in the control of position, force and compliance (mechanical impedance) of hand. Obtained results are summarized as follows. (1) Method of estimating mechano-chemical coefficients of human skeletal muscles was developed. (2) viscoelastic coefficients of the flexor and extensor thumb muscles were estimated. (3) The viscoelastic coefficients varied linearly with increasing the force exerted in the voluntary isometric contraction. (4) Both dynamic propertics of the stretch reflex and those of the mechanical impedance in position and force control of the thumb were estimated by using a mathematical model. (5) Gain of the stretch reflex as well as the mechanical impedance were enhanced when producing larger muscle force or controlling the position of unstable load. (6) Angles of individual joints in the upper arm and force applied to the paper were measured in letter-writing motion in man. Control mechanisms of the central nervous system in letter-writing were analyzed by the model.