Department of Health and Human Performance, University of Texas at Brownsville, 80 Fort Brown, Brownsville, TX 78520, USA.
Exp Brain Res. 2012 Dec;223(4):533-9. doi: 10.1007/s00221-012-3280-8. Epub 2012 Oct 2.
Prior research has concluded that the correlations of isometric finger forces represent the extent to which the fingers are controlled as a single unit. If this is the case, finger force correlations should be consistent with estimates of the controlled (dynamical) degrees of freedom in finger forces. The present study examined the finger force correlations and the dynamical degrees of freedom in four isometric force tasks. The tasks were to produce a preferred level of force with the (a) Index, (b) Ring, (c) Both fingers and also to (d) Rest the fingers on the load cells. Dynamical degrees of freedom in finger forces were lowest in the Both finger force task and progressively higher in the Ring, Index and Resting finger force tasks. The finger force correlations were highest in the Resting and lowest in the Index and Ring finger tasks. The results for the dynamical degrees of freedom in finger forces were consistent with a reduction in degrees of freedom in response to the degrees of freedom problem and the task constraints. The results for the finger force correlations were inconsistent with a reduction in the dynamical degrees of freedom. These findings indicate that finger force correlations do not necessarily reflect the coupling of finger forces. The findings also highlight the value of time-domain analyses to reveal the organization of control in isometric finger forces.
先前的研究得出结论，等长手指力的相关性表示手指作为一个整体被控制的程度。如果是这样，手指力的相关性应该与手指力的受控（动力学）自由度的估计一致。本研究在四项等长力任务中检查了手指力的相关性和动力学自由度。任务是用（a）食指、（b）无名指、（c）两个手指产生一个偏好的力水平，以及（d）将手指放在负载单元上。手指力的动力学自由度在两个手指力任务中最低，在无名指、食指和休息手指力任务中逐渐升高。手指力的相关性在休息任务中最高，在食指和无名指任务中最低。手指力动力学自由度的结果与自由度问题和任务约束下自由度的减少一致。手指力相关性的结果与动力学自由度的减少不一致。这些发现表明，手指力的相关性不一定反映手指力的耦合。这些发现还突出了时域分析的价值，以揭示等长手指力控制的组织。
