Slobounov S, Chiang H, Johnston J, Ray W
Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802-5702, USA.
Clin Neurophysiol. 2002 Dec;113(12):2013-24. doi: 10.1016/s1388-2457(02)00298-5.
The present research was designed to address the nature of interdependency between fingers during force production tasks in subjects with varying experience in performing independent finger manipulation. Specifically, behavioral and electroencephalographic (EEG) measures associated with controllability of the most enslaved (ring) and the least enslaved (index) fingers was examined in musicians and non-musicians.
Six piano players and 6 age-matched control subjects performed a series of isometric force production tasks with the index and ring fingers. Subjects produced 3 different force levels with either their index or ring fingers. We measured the isometric force output produced by all 4 fingers (index, ring, middle and little), including both ramp and static phases of force production. We applied time-domain averaging of EEG single trials in order to extract 4 components of the movement-related cortical potentials (MRCP) preceding and accompanying force responses.
Three behavioral findings were observed. First, musicians were more accurate than non-musicians at reaching the desired force level. Second, musicians showed less enslaving as compared to non-musicians. And third, the amount of enslaving increased with the increment of nominal force levels regardless of whether the index or ring finger was used as the master finger. In terms of EEG measures, we found differences between tasks performed with the index and ring fingers in non-musicians. For musicians, we found larger MRCP amplitudes at most electrode sites for the ring finger.
Our data extends previous enslaving research and suggest an important role for previous experience in terms of the independent use of the fingers. Given that a variety of previous work has shown finger independence to be reflected in cortical representation in the brain and our findings of MRCP amplitude associated with greater independence of fingers in musicians, this suggests that what has been considered to be stable constraints in terms of finger movements can be modulated by experience.
This work supports the idea that experience is associated with changes in behavioral and EEG correlates of task performance and may have clinical implications in disorders such as stroke or focal hand dystonia. Practice-related procedures offer useful approaches to rehabilitation strategies.
本研究旨在探讨在执行独立手指操作经验各异的受试者进行力量产生任务时手指间相互依赖的本质。具体而言，研究考察了音乐家和非音乐家中与最受束缚（无名指）和最不受束缚（食指）手指可控性相关的行为和脑电图（EEG）指标。
6名钢琴演奏者和6名年龄匹配的对照受试者用食指和无名指进行了一系列等长力量产生任务。受试者用食指或无名指产生3种不同的力量水平。我们测量了所有4根手指（食指、无名指、中指和小指）产生的等长力量输出，包括力量产生的斜坡阶段和静态阶段。我们应用EEG单次试验的时域平均法，以提取力量反应之前和伴随力量反应的运动相关皮层电位（MRCP）的4个成分。
观察到三个行为学发现。第一，在达到期望力量水平方面，音乐家比非音乐家更准确。第二，与非音乐家相比，音乐家表现出的受束缚程度更低。第三，无论将食指还是无名指用作主导手指，受束缚程度都随名义力量水平的增加而增加。在EEG指标方面，我们发现非音乐家中用食指和无名指执行任务时存在差异。对于音乐家，我们发现无名指在大多数电极部位的MRCP振幅更大。
我们的数据扩展了先前关于受束缚的研究，并表明先前经验在手指独立使用方面具有重要作用。鉴于先前的各种研究表明手指独立性在大脑皮层表征中有所体现，且我们发现音乐家手指独立性更高与MRCP振幅相关，这表明在手指运动方面被认为是稳定的限制因素可因经验而调节。
这项工作支持了这样一种观点，即经验与任务表现的行为和EEG相关性变化相关，可能对中风或局灶性手部肌张力障碍等疾病具有临床意义。与练习相关的程序为康复策略提供了有用的方法。
