TASK-DEPENDENT CHANGES IN THE RESPONSE OF HUMAN WRIST JOINTS TO MECHANICAL DISTURBANCE
TASK-DEPENDENT CHANGES IN THE RESPONSE OF HUMAN WRIST JOINTS TO MECHANICAL DISTURBANCE
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DOI：
10.1113/jphysiol.1992.sp019019
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发表时间：
1992-02-01
影响因子：
5.5
通讯作者：
RACK, PMH
中科院分区：
文献类型：
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作者：
DOEMGES, F;RACK, PMH
1. 受试者坐在一个连接到伺服控制马达轴的模具中，右手放在模具中。 有两个不同的任务。 在一个实验中，受试者试图保持恒定的手腕弯曲力，而电机施加弯曲-伸展运动。 在另一种情况下，受试者试图保持恒定的手腕位置，而电机施加可变的屈伸力。 “保持力量”任务被随机定时的斜坡伸展运动打断，以测试牵张反射活动。 "保持位置"任务被力的变化打断，这些变化与上面提到的坡道延伸期间记录的变化相同。 通过这种方式，可以在“保持力”和“保持位置”任务期间使用相同的干扰来测试牵张反射。 当经过一些练习后，受试者变得善于保持恒定的力量时，牵张反射的后期成分（40 ms后）被发现比他们保持恒定位置时要小。 试图保持一个恒定的位置往往涉及共同激活的腕伸肌。 这可以通过桡神经的局部麻醉来预防。 屈肌的长潜伏期牵张反射在这之后仍然是任务依赖性的。 6. 共激活和任务相关的反射反应的作用进行了讨论。
1. Subjects sat with their right hands in a mould which was attached to the shaft of a servo-controlled motor.2. There were two different tasks. In one, the subject attempted to maintain a constant wrist flexing force, while the motor imposed flexion-extension movements. In the other, the subject attempted to maintain a constant wrist position while the motor exerted variable flexion-extension forces.3. The 'maintain force' task was punctuated by randomly timed ramp extension movements to test the stretch reflex activity. The 'maintain position' task was punctuated by force changes which were the same as those recorded during the ramp extensions mentioned above. In this way it was possible to test stretch reflexes with the same disturbance during the 'maintain force' and 'maintain position' tasks.4. When, after some practice, subjects had become good at maintaining the constant force, later components of the stretch reflex (after 40 ms) were found to be smaller than when they were maintaining a constant position.5. Attempts to maintain a constant position often involved co-activation of the wrist extensor muscles. This could be prevented by local anaesthesia of the radial nerve. The long-latency stretch reflex of the flexors was still task dependent after this had been done. 6. The roles of co-activation and of task-dependent reflex responses are discussed.