van den Heuvel Maarten R C, Balasubramaniam Ramesh, Daffertshofer Andreas, Longtin André, Beek Peter J
Research Institute MOVE, VU University Amsterdam, Amsterdam, The Netherlands.
Neurosci Lett. 2009 Mar 6;452(1):37-41. doi: 10.1016/j.neulet.2009.01.024.
We performed an experiment in which we challenged postural stability in 12 healthy subjects by providing artificial delayed visual feedback. A monitor at eye-height presented subjects with a visual representation of the location of their center-of-pressure (COP) and they were instructed to position their COP as accurately as possible on a small target. Visual feedback of the COP was displayed either in real-time, or delayed by 250, 500, 750, or 1000 ms. In a control condition, no visual feedback was provided. As expected, stability increased during real-time visual feedback compared to when feedback was absent. To identify time scales at which postural control during quiet stance takes place we sought to distinguish between different frequencies. Low frequencies, i.e. slow components of postural sway, showed a monotonic increase in sway amplitude with increasing delay, whereas high frequencies, i.e. fast components of postural sway, showed significantly reduced sway amplitude for delays of 500-750 ms compared to the other delay conditions. Low- and high-frequency components of postural sway thus exhibited differential susceptibility to artificial delays, thereby supporting the notion of postural control taking place on two distinct time scales.
我们进行了一项实验，通过提供人工延迟视觉反馈来挑战12名健康受试者的姿势稳定性。在受试者眼睛高度的监视器上呈现其压力中心（COP）位置的视觉表示，并指示他们尽可能准确地将其COP定位在一个小目标上。COP的视觉反馈要么实时显示，要么延迟250、500、750或1000毫秒。在对照条件下，不提供视觉反馈。正如预期的那样，与没有反馈时相比，实时视觉反馈期间稳定性增加。为了确定安静站立时姿势控制发生的时间尺度，我们试图区分不同频率。低频，即姿势摆动的缓慢成分，随着延迟增加，摆动幅度呈单调增加，而高频，即姿势摆动的快速成分，与其他延迟条件相比，在延迟500 - 750毫秒时摆动幅度显著降低。姿势摆动的低频和高频成分因此对人工延迟表现出不同的敏感性，从而支持了姿势控制在两个不同时间尺度上发生的观点。
