Task-dependent modulation of multi-digit force coordination patterns.
Task-dependent modulation of multi-digit force coordination patterns.
复制标题
多位部队协调模式的任务相关调制。
DOI：
10.1152/jn.00581.2002
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Santello,Marco
中科院分区：
文献类型：
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作者：
Rearick,MatthewP;Casares,Amparo;Santello,Marco
当在各种任务约束下抓握和握住一个五指物体时，受试者使用定义明确的力协调模式，即，所有数字对之间一致的力协变和同相同步。问题是，这些力的协调模式是否是控制多指力产生的默认机制，或者它们是否是特定于举起和握住物体的。为了解决这个问题，我们要求受试者抓住一个manipulgiant和同时施加五个手指的力量，以匹配从实际物体抓取，提升和保持任务（GLH）测量的力模板。与GLH不同，力产生任务（FP）缺乏必须保持物体稳定对抗重力的约束。单个手指力的幅度和力协变对于两个任务是相似的（除了小指，其倾向于在FP中产生较小的力）。尽管如此，当不需要多个夹持力来对抗重力（FP）时，所有手指对施加的力之间的相位差具有较高的试验间变异性，力同步的趋势明显较低。此外，力相位差在0°处聚集的趋势对于FP比GLH低。这些结果表明，多指抓握控制的某些方面，即，力同步是特定于物体提升和保持的，而不是多位力的产生。建模工作表明，运动单位的同步可能发挥重要作用的调制力同步模式。
When grasping and holding an object with five digits under a variety of task constraints, subjects use well-defined force coordination patterns, i.e., consistent force covariations and in-phase synchronization among all digit pairs. The question arises as to whether these force coordination patterns are default mechanisms for controlling multi-digit force production or whether they are specific to lifting and holding an object. To address this question, we asked subjects to grasp a manipulandum and exert forces with five digits simultaneously so as to match a force template measured from an actual object grasp, lift, and hold task (GLH). Unlike GLH, the force production task (FP) lacked the constraint of having to maintain object stability against gravity. The amplitude of individual finger forces and force covariations were similar for both tasks (with the exception of the little finger, which tended to produce less force in FP). Nonetheless, when multiple grip forces were not required to hold the manipulandum against gravity (FP), there was a significantly lower tendency for forces to be synchronized with higher intertrial variability of phase differences between forces exerted by all digit-pairs. Furthermore, the tendency for force phase differences to cluster at 0° was lower for FP than GLH. These results suggest that some aspects of the control of multi-digit grasping, i.e., force synchronization, are specific to object lift and hold rather than to the production of multi-digit forces. Modeling work suggests that motor unit synchronization might play an important role in the modulation of force synchronization patterns.