Independent control of movements between the fingers plays a role in hand dexterity characterizing skilled individuals. However, it remains unknown whether and in what manner neuromuscular and biomechanical constraints on the movement independence of the fingers depend on motor expertise. Here, we compared motor dexterity, corticospinal excitability of multiple muscles, muscular activation, and anatomical features of the fingers between the pianists and nonpianists. When the ring finger was passively moved by a robot, passive motions produced at the adjacent fingers were smaller for the pianists than the nonpianists, indicating reduced biomechanical constraint of fingers in the pianists. In contrast, when the ring finger moved actively, we found no group difference in passive motions produced at the adjacent fingers; however, reduced inhibition of corticospinal excitability of the adjacent fingers in the pianists compared with the nonpianists. This suggests strengthened neuromuscular coupling between the fingers of the pianists, enhancing the production of coordinated finger movements. These group differences were not evident during the index and little finger movements. Together, pianists show expertise-dependent biomechanical and neurophysiological adaptations, specifically at the finger with innately low movement independence. Such contrasting adaptations of pianists may subserve dexterous control of both the individuated and coordinated finger movements.

中文翻译：

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钢琴家皮质肌肉和生物力学系统的适应

手指间运动的独立控制对熟练个体的手部灵巧性具有重要作用。然而，尚不清楚手指运动独立性的神经肌肉和生物力学限制是否以及以何种方式取决于运动专业知识。在这里，我们比较了钢琴家和非钢琴家之间的运动灵活性、多块肌肉的皮质脊髓兴奋性、肌肉激活和手指的解剖特征。当无名指被机器人被动移动时，钢琴家的相邻手指产生的被动运动小于非钢琴家，这表明钢琴家手指的生物力学约束减少。相反，当无名指主动运动时，我们发现相邻手指产生的被动运动没有组差异；然而，与非钢琴演奏者相比，钢琴演奏者对相邻手指皮质脊髓兴奋性的抑制作用降低。这表明钢琴家手指之间的神经肌肉耦合得到了加强，从而提高了协调手指运动的产生。这些组差异在食指和小指运动期间并不明显。一起，钢琴家展示了依赖于专业知识的生物力学和神经生理学适应，特别是在具有天生低运动独立性的手指上。钢琴家的这种对比适应可能有助于灵巧地控制个性化和协调的手指运动。增强协调手指动作的产生。这些组差异在食指和小指运动期间并不明显。一起，钢琴家展示了依赖于专业知识的生物力学和神经生理学适应，特别是在具有天生低运动独立性的手指上。钢琴家的这种对比适应可能有助于灵巧地控制个性化和协调的手指运动。增强协调手指动作的产生。这些组差异在食指和小指运动期间并不明显。一起，钢琴家展示了依赖于专业知识的生物力学和神经生理学适应，特别是在具有天生低运动独立性的手指上。钢琴家的这种对比适应可能有助于灵巧地控制个性化和协调的手指运动。