Ambike Satyajit, Mattos Daniela, Zatsiorsky Vladimir, Latash Mark
1 Purdue University.
2 University of Missouri.
Motor Control. 2018 Jan 1;22(1):82-99. doi: 10.1123/mc.2016-0082. Epub 2017 Sep 11.
Cyclic isometric finger-force patterns established using visual feedback show systematic drifts when the feedback is removed. Force changes at multiple time scales and in opposite directions have been reported. For further characterization of these drifts, healthy subjects produced isometric, cyclic finger force with and without visual feedback at various initial amplitudes and frequencies. We hypothesized that on feedback removal, the amplitude will be attracted toward a preferred value that is frequency dependent. We found that the amplitude always increased after feedback removal. The magnitude of the amplitude increase changed with initial frequency, but it was invariant over the explored range of initial amplitudes. Thus, the existence of a preferred amplitude of force oscillations was not supported. We interpret these results within the referent configuration and the referent configuration back-coupling hypotheses. These data will inform a mathematical model of finger-force drifts. However, currently, they raise more questions than they answer, and a coherent account of finger-force drifts remains a challenge.
利用视觉反馈建立的周期性等长手指力模式在移除反馈时会出现系统性漂移。已有报告称力在多个时间尺度上且方向相反地发生变化。为了进一步表征这些漂移，健康受试者在有和没有视觉反馈的情况下，以各种初始幅度和频率产生等长周期性手指力。我们假设在移除反馈后，幅度将被吸引到一个与频率相关的偏好值。我们发现移除反馈后幅度总是增加。幅度增加的大小随初始频率而变化，但在初始幅度的探索范围内是不变的。因此，力振荡的偏好幅度的存在未得到支持。我们在参考构型和参考构型反向耦合假设内解释这些结果。这些数据将为手指力漂移的数学模型提供信息。然而，目前，它们提出的问题比回答的问题更多，对手指力漂移的连贯解释仍然是一个挑战。
