Department of Experimental Medicine, Section of Human Physiology and Istituto Nazionale di Neuroscienze, University of Genoa, Italy.
Neuroscience. 2009 Dec 29;164(4):1601-8. doi: 10.1016/j.neuroscience.2009.09.053. Epub 2009 Sep 25.
Balance control depends on the interaction of multiple inputs originating from different sensory systems. Here, we investigated the effect on quiet human stance of changing the visual condition prior to a proprioceptive perturbation produced by vibration of dorsal neck muscles. In complete absence of visual references, the amplitude of the postural responses to neck vibration (forward shift of the centre of foot pressure) was the largest and became progressively larger as a function of the repetition of administered stimuli. The posture-destabilizing effect of vibration eyes-closed (EC) and the build-up effect were reduced if vibration was preceded by a period during which vision was allowed (EO). Similarly, the small destabilizing effect of vibration EO was increased if vibration was preceded by an EC period. The fore-period must last more than 3 s in order to affect the response to neck muscle vibration. The responsiveness to a proprioceptive disturbing input does not immediately change on adding or subtracting vision, but a finite time period must elapse before the postural "set" defined by vision is fully established. The findings underline the importance of time when vision is used in re-weighting the excitability of the postural control mechanisms.
平衡控制取决于源自不同感觉系统的多个输入的相互作用。在这里，我们研究了在颈部肌肉振动产生本体感受干扰之前改变视觉条件对安静人体姿势的影响。在完全没有视觉参考的情况下，颈部振动（足底压力中心向前移动）引起的姿势反应幅度最大，并且随着给予刺激的重复而逐渐增大。如果在振动之前允许视觉（EO），则振动闭眼（EC）对姿势的稳定作用和建立作用会降低。同样，如果在 EC 期之前有一个振动期，振动 EO 的小稳定作用会增加。前周期必须持续超过 3 秒，才能影响颈部肌肉振动的反应。对本体感受干扰输入的反应不会立即在添加或减去视觉时发生变化，而是必须经过一定的时间间隔，才能完全建立由视觉定义的姿势“设定”。这些发现强调了当视觉用于重新调整姿势控制机制的兴奋性时，时间的重要性。
