Pavlova Elena, Kuo Min-Fang, Nitsche Michael A, Borg Jörgen
Department of Clinical Sciences, Rehabilitation medicine, Karolinska Institute, Danderyd Hospital, entrée 39, floor 3, 18288 Stockholm, Sweden.
Department of Clinical Neurophysiology, Georg-August-Universität Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany.
Brain Res. 2014 Aug 12;1576:52-62. doi: 10.1016/j.brainres.2014.06.023. Epub 2014 Jun 27.
Premotor cortex activity is associated with complex motor performance and motor learning and offers a potential target to improve dexterity by transcranial direct current stimulation (tDCS). We explored the effects of tDCS of premotor cortex on performance of a Strength-Dexterity test in healthy subjects.
During the test a slender spring held between thumb and index finger should be compressed as much as possible without buckling. Finger forces assessed in the test provided a measure of dexterity. First, task performance was tested in 12 persons during anodal tDCS to the primary motor cortex (M1) contralateral to the performing hand, and sham stimulation. Another 12 persons participated in five sessions of anodal and cathodal tDCS over the left and the right premotor cortex and sham stimulation.
tDCS over M1 as well as over the left, but not the right premotor cortex resulted in significant improvement of performance. Performance alterations correlated positively between left anodal and right cathodal tDCS and negatively between anodal tDCS of the two sides. Effective polarity for premotor stimulation to improve task performance differed between participants. Individuals who improved with anodal stimulation used lower finger force and experienced the test as more difficult compared to those who improved with cathodal stimulation.
This study demonstrates that tDCS over the left premotor cortex can improve performance of a dexterity demanding task. The effective polarity of stimulation depends on the task performance strategies. The study moreover shows a functional relevance of interactions between the left and right premotor cortex.
运动前区皮质活动与复杂运动表现及运动学习相关，为经颅直流电刺激（tDCS）改善灵活性提供了一个潜在靶点。我们探讨了运动前区皮质tDCS对健康受试者力量 - 灵活性测试表现的影响。
在测试过程中，需用拇指和食指尽可能压缩一根细长弹簧而不使其弯曲。测试中评估的手指力量可衡量灵活性。首先，在12名受试者对执行手对侧的初级运动皮质（M1）进行阳极tDCS及假刺激期间测试任务表现。另外12名受试者参与了在左侧和右侧运动前区皮质进行的五节阳极和阴极tDCS及假刺激。
M1以及左侧而非右侧运动前区皮质的tDCS导致表现显著改善。左侧阳极和右侧阴极tDCS之间的表现改变呈正相关，两侧阳极tDCS之间呈负相关。运动前区刺激改善任务表现的有效极性在受试者之间存在差异。与阴极刺激改善的受试者相比，阳极刺激改善的个体使用较低的手指力量，且感觉测试更困难。
本研究表明，左侧运动前区皮质的tDCS可改善对灵活性要求较高任务的表现。刺激的有效极性取决于任务表现策略。该研究还显示了左右运动前区皮质之间相互作用的功能相关性。
