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首页> 外文期刊>Journal of Neurophysiology >Coordination between digit forces and positions: interactions between anticipatory and feedback control
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Coordination between digit forces and positions: interactions between anticipatory and feedback control

机译：数字力和位置之间的协调：预期和反馈控制之间的相互作用

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Humans adjust digit forces to compensate for trial-to-trial variability in digit placement during object manipulation, but the underlying control mechanisms remain to be determined. We hypothesized that such digit position/force coordination was achieved by both visually guided feed-forward planning and haptic-based feedback control. The question arises about the time course of the interaction between these two mechanisms. This was tested with a task in which subjects generated torque (±70 N-mm) on a virtual object to control a cursor moving to target positions to catch a falling ball, using a virtual reality environment and haptic devices. The width of the virtual object was varied between large (L) and small (S). These object widths result in significantly different horizontal digit relative positions and require different digit forces to exert the same task torque. After training, subjects were tested with random sequences of L and S widths with or without visual information about object width. We found that visual cues allowed subjects to plan manipulation forces before contact. In contrast, when visual cues were not available to predict digit positions, subjects implemented a "default" digit force plan that was corrected after digit contact to eventually accomplish the task. The time course of digit forces revealed that force development was delayed in the absence of visual cues. Specifically, the appropriate digit force adjustments were made 250-300 ms after initial object contact. This result supports our hypothesis and further reveals that haptic feedback alone is sufficient to implement digit force-position coordination.
机译：人类调整手指力以补偿在对象操纵过程中手指放置的试验间差异，但是潜在的控制机制仍有待确定。我们假设通过视觉引导的前馈计划和基于触觉的反馈控制都可以实现这种手指位置/力的协调。出现关于这两种机制之间相互作用的时间过程的问题。这是通过一项任务进行测试的，其中受试者使用虚拟现实环境和触觉设备在虚拟物体上产生扭矩（±70 N-mm），以控制光标移动到目标位置以接住落球。虚拟对象的宽度在大（L）和小（S）之间变化。这些物体的宽度导致水平手指的相对位置明显不同，并且需要不同的手指力来施加相同的工作扭矩。训练后，对受试者进行L和S宽度的随机序列测试，无论是否具有关于物体宽度的视觉信息。我们发现视觉提示可以使受试者在接触之前计划操纵力。相反，当视觉提示无法预测手指位置时，受试者实施“默认”手指力计划，在手指接触后对其进行校正以最终完成任务。手指力量的时程表明，在没有视觉提示的情况下，力量的发展被延迟了。具体地，在初始物体接触后250-300ms进行适当的手指力调节。该结果支持了我们的假设，并进一步揭示了仅凭触觉反馈就足以实现数字力-位置协调。

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