Santello M, Flanders M, Soechting J F
Neuroscience Department, University of Minnesota, Minneapolis, Minnesota 55455, USA.
J Neurosci. 1998 Dec 1;18(23):10105-15. doi: 10.1523/JNEUROSCI.18-23-10105.1998.
Subjects were asked to shape the right hand as if to grasp and use a large number of familiar objects. The chosen objects typically are held with a variety of grips, including "precision" and "power" grips. Static hand posture was measured by recording the angular position of 15 joint angles of the fingers and of the thumb. Although subjects adopted distinct hand shapes for the various objects, the joint angles of the digits did not vary independently. Principal components analysis showed that the first two components could account for >80% of the variance, implying a substantial reduction from the 15 degrees of freedom that were recorded. However, even though they were small, higher-order (more than three) principal components did not represent random variability but instead provided additional information about the object. These results suggest that the control of hand posture involves a few postural synergies, regulating the general shape of the hand, coupled with a finer control mechanism providing for small, subtle adjustments. Because the postural synergies did not coincide with grip taxonomies, the results suggest that hand posture may be regulated independently from the control of the contact forces that are used to grasp an object.
受试者被要求将右手做出仿佛要抓握和使用大量熟悉物体的形状。所选择的物体通常要用各种抓握方式来握持，包括“精细”抓握和“强力”抓握。通过记录手指和拇指的15个关节角度的角位置来测量静态手部姿势。尽管受试者针对不同物体采用了不同的手部形状，但手指的关节角度并非独立变化。主成分分析表明，前两个成分可解释超过80%的方差，这意味着与所记录的15个自由度相比有大幅减少。然而，尽管高阶（超过三个）主成分较小，但它们并非代表随机变异性，而是提供了有关物体的额外信息。这些结果表明，手部姿势的控制涉及一些姿势协同作用，调节手部的总体形状，同时还有一个更精细的控制机制用于进行微小、细微的调整。由于姿势协同作用与抓握分类法不一致，结果表明手部姿势可能独立于用于抓握物体的接触力的控制进行调节。
