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

本研究的目的是探讨自主精确手运动的神经机制，即，手的位置、力和顺应性（机械阻抗）的控制。所得结果总结如下。(1)提出了一种估算人体骨骼肌力学化学系数的方法。(2)估计拇指屈肌和伸肌的粘弹性系数。(3)粘弹性系数随主动等长收缩力的增加而线性变化。(4)利用数学模型估计了牵张反射的动态特性和拇指位置和力控制的机械阻抗的动态特性。(5)当产生较大的肌肉力量或控制不稳定负荷的位置时，牵张反射的增益和机械阻抗都增加。(6)通过测量人在书写过程中上臂各关节的角度和纸上所受的力，分析了书写过程中中枢神经系统的控制机制。

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.