Forghani Ali, Preuss Richard, Milner Theodore
Center for Applied Biomechanics, University of Virginia, Charlottesville, USA.
Department of Physical and Occupational Therapy, McGill University, Montreal, Canada.
J Electromyogr Kinesiol. 2017 Feb;32:83-92. doi: 10.1016/j.jelekin.2016.12.003. Epub 2016 Dec 20.
When the arm of a standing human is perturbed in an unpredictable direction, postural muscles are activated at latencies as short as 50-110ms. While the motion of the body clearly progresses in hand-to-leg sequence, there is no systematic muscle activation sequence from the arm to the leg muscles, suggesting that the activation of the muscles is not likely the result of local stretch reflexes. In fact, the lower limb muscles are activated before the upright posture is significantly disturbed. The short-latency activation amplitude and the activation probability are clearly tuned to the direction of the arm perturbation for both rostral and caudal muscles. The effect of central set on the short-latency response has been investigated by manipulating the predictability of the perturbations. Possible underlying neural mechanisms have been discussed.
当站立的人的手臂受到不可预测方向的扰动时，姿势肌肉会在短至50 - 110毫秒的潜伏期被激活。虽然身体的运动明显按照手到腿的顺序进行，但从手臂肌肉到腿部肌肉并没有系统的肌肉激活顺序，这表明肌肉的激活不太可能是局部牵张反射的结果。事实上，在直立姿势受到明显干扰之前，下肢肌肉就已经被激活。对于头部和尾部的肌肉，短潜伏期激活幅度和激活概率都明显根据手臂扰动的方向进行了调整。通过操纵扰动的可预测性，研究了中枢设定对短潜伏期反应的影响。文中还讨论了可能的潜在神经机制。
