Department of Human Movement Science, Incheon National University, Incheon, South Korea.
Division of Sport Science, Neuromechanical Rehabilitation Research Laboratory, Incheon National University, 119 Academy-Ro, Yeonsu-Gu, Incheon, South Korea.
Exp Brain Res. 2023 Jan;241(1):313-323. doi: 10.1007/s00221-022-06526-0. Epub 2022 Dec 13.
This study aimed to investigate the potential effect of bilateral transcranial direct current stimulation (tDCS) on repetitive bimanual force control and force coordination in healthy young adults. In this sham-controlled crossover study, 18 right-handed young adults were enrolled. Repetitive bimanual handgrip force control trials were performed by the participants at 40% of maximum voluntary contraction until task failure. We randomly provided bilateral active and sham tDCS to the primary motor cortex (M1) of each participant before conducting the repetitive bimanual force control task. We quantified the number of successful trials to assess the ability to maintain bimanual force control across multiple trials. Moreover, we estimated bimanual force control and force coordination by quantifying force accuracy, variability, regularity, and correlation coefficient in maximal and adjusted successful trials. Force asymmetry was calculated to examine potential changes in motor dependency on each hand during the task. Bilateral tDCS significantly increased the number of successful trials compared with sham tDCS. The adjusted successful trial revealed that participants who received bilateral tDCS maintained better bimanual force control and coordination, as indicated by decreased force variability and regularity as well as more negative correlation coefficient values in comparison with sham condition. Moreover, participants who received bilateral tDCS produced more force from the dominant hand than from the nondominant hand in both maximal and adjusted successful trials. These findings suggest that bilateral tDCS on M1 successfully maintains bimanual force control with better force coordination by modulating motor dependency.
本研究旨在探究双侧经颅直流电刺激（tDCS）对健康年轻成年人重复双手力控制和力协调的潜在影响。在这项假刺激对照交叉研究中，纳入了 18 名右利手的年轻成年人。参与者以 40%最大自主收缩力进行重复双手握力控制试验，直至任务失败。在进行重复双手力控制任务之前，我们随机向每位参与者的初级运动皮层（M1）提供双侧主动和假刺激 tDCS。我们通过量化成功试验的数量来评估在多次试验中维持双手力控制的能力。此外，我们通过量化最大和调整后成功试验中的力准确性、变异性、规律性和相关系数来估计双手力控制和力协调。力不对称性用于检查任务过程中每只手的运动依赖性的潜在变化。与假刺激 tDCS 相比，双侧 tDCS 显著增加了成功试验的数量。调整后成功试验表明，与假刺激条件相比，接受双侧 tDCS 的参与者在双手力控制和协调方面保持更好，表现为力变异性和规律性降低，以及相关系数值更负。此外，在最大和调整后成功试验中，接受双侧 tDCS 的参与者从优势手产生的力大于非优势手。这些发现表明，M1 双侧 tDCS 通过调节运动依赖性成功地维持了双手力控制，具有更好的力协调。
