PHASE-DEPENDENT MODULATIONS OF ANTICIPATORY POSTURAL ACTIVITY DURING HUMAN LOCOMOTION
PHASE-DEPENDENT MODULATIONS OF ANTICIPATORY POSTURAL ACTIVITY DURING HUMAN LOCOMOTION
复制标题
DOI：
10.1152/jn.1991.66.1.12
复制
发表时间：
1991-07-01
影响因子：
2.5
通讯作者：
FORSSBERG, H
中科院分区：
文献类型：
--
作者：
HIRSCHFELD, H;FORSSBERG, H
1. 研究了人类在跑步机上拉动手柄行走时中枢神经系统协调多项运动任务的能力。受试者被指示对在步进周期的不同阶段出现的音频信号做出反应。记录左臂和左腿的肌电图（EMG）和运动。2．手臂肌肉的活动先于腿部肌肉的姿势活动。预期姿势活动的模式在步伐周期的各个阶段有所不同。腓肠肌外侧肌和腘绳肌在早期支撑阶段发生的反应期间被激活，而胫骨前肌和股四头肌在后期支撑阶段和摆动阶段施加拉力时被激活。在支撑阶段的中间，存在两种肌肉活动的组合。3．预期肌肉活动的时间顺序和空间分布逐渐改变。在支撑阶段的早期，腘绳肌在腓肠肌之前被激活，而在中间阶段则顺序相反。腘绳肌和腓肠肌的肌电波幅在支撑阶段开始时最大，然后逐渐减小，而胫骨前肌和股四头肌的肌电波幅在支撑阶段后期逐渐增加。4．在支撑阶段的第一部分期间对施加的拉力的预期反应减少了单一支撑阶段期间的踝关节弯曲。随后，在支撑阶段结束时的推离过程中，踝关节伸展延迟并减少。在支撑阶段后期触发的预期反应也会延迟并减少推出时的脚踝伸展。5。姿势调整的阶段依赖性修改表明身体在中枢神经系统不同层面的内部表征，并随着运动的持续更新而变化。在高水平上，大脑回路可以结合拉力来编程姿势反应。此后，姿势反应可能会根据运动网络和外周反射相互作用所施加的中央门控的步进周期进行调整。
1. The ability of the CNS to coordinate several motor tasks was studied in humans walking on a treadmill while pulling on a handle. Subjects were instructed to respond to an audio signal that was presented in different phases of the step cycle. Electromyograph (EMG) and movements were recorded from the left arm and leg.2. The activity of the arm muscle was preceded by postural activity in the leg muscles. The pattern of the anticipatory postural activity differed in the various phases of the step cycle. Lateral gastrocnemius and hamstring muscles were activated during responses occurring in the early support phase whereas tibialis anterior and quadriceps muscles were activated when the pull was exerted during the late support phase and during the swing phase. In the middle of the support phase the combination of both muscle activity was present.3. The temporal sequencing and the spatial distribution of the anticipatory muscle activity changed gradually. Early during the support phase the hamstring muscles were activated before the gastrocnemius muscle, whereas the order was reversed during midstance. The EMG amplitude of the hamstring and gastrocnemius muscles was largest in the beginning of the support phase and then gradually decreased, whereas the amplitude of the tibialis anterior and quadriceps muscles increased during the later parts of the support phase.4. The anticipatory responses to pulls exerted during the first part of the support phase reduced the ankle flexion during the single support phase. This was followed by a delayed and decreased ankle extension during the push-off at the end of the support phase. Anticipatory responses triggered during later parts of the support phase also delayed and reduced the ankle extension at push-off.5. The phase-dependent modifications of the postural adjustment suggest an internal representation of the body at different levels of the CNS with a continuous update with respect to the locomotor movements. At a high level, cerebral circuits may program the postural response in conjunction with the pull. The postural response might thereafter be tuned in accordance with the step cycle by central gating, exerted by the locomotor network and peripheral reflex interactions.