Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA.
Neurosci Lett. 2010 Jan 18;469(1):131-4. doi: 10.1016/j.neulet.2009.11.059. Epub 2009 Nov 26.
This study investigated the effect of selectively increasing the visual scale of the high frequency components on isometric force control. The higher frequency bandwidths (4-8 Hz or 8-12 Hz) of the force output were amplified visually by a scaling factor (0, 2, 4, 6, 8). Four types of force targets (i.e. constant, sine function, pink noise, and brown noise) that required different control strategies were examined. In the constant and to a lesser extent the pink noise task the enhanced visual scaling information progressively reduced the contribution to the force signal of the respective (4-8 Hz or 8-12 Hz) bandwidth and also in the neighboring frequency bandwidths (0-4 Hz or 4-8 Hz). The frequency analysis in the constant target condition showed that selectively increasing the visual scale of the high frequency bandwidths changed the whole frequency spectrum of the potential adaptive force range (0-12 Hz) rather than only the specific bandwidth being scaled. This rescaling of the whole frequency spectrum led, however, to increase performance error in the constant and sine function targets. These findings show that the multiple time scale process of isometric force control are constrained by the predictive properties of the force output and the relative contribution of feedforward and feedback processes to task outcome.
本研究考察了选择性地增加高频分量视觉比例对等长力控制的影响。通过缩放因子（0、2、4、6、8）对力输出的较高频带（4-8 Hz 或 8-12 Hz）进行视觉放大。检查了需要不同控制策略的四种力目标（即恒定、正弦函数、粉红噪声和布朗噪声）。在恒定目标和在较小程度上在粉红噪声任务中，增强的视觉缩放信息逐渐减少了各自（4-8 Hz 或 8-12 Hz）带宽和相邻频率带宽（0-4 Hz 或 4-8 Hz）对力信号的贡献。在恒定目标条件下的频率分析表明，选择性地增加高频带宽的视觉比例改变了潜在自适应力范围（0-12 Hz）的整个频谱，而不仅仅是被缩放的特定带宽。然而，这种整个频谱的重新缩放导致在恒定和正弦函数目标中的性能误差增加。这些发现表明，等长力控制的多时间尺度过程受到力输出的预测特性以及前馈和反馈过程对任务结果的相对贡献的限制。
