Transcranial Direct Current Stimulation (tDCS) modulates motor execution in a limb reaching task.

The majority of human activities show a trade-off between movement speed and accuracy. Here we tested 16 participants in a quick pointing action after 20 minutes (2mA) of transcranial Direct Current Stimulation (tDCS) delivered at the Supplementary Motor Area (SMA) in a single-blind crossover design study for testing the feedforward components in the control of action. tDCS stimuli were delivered in three randomized sessions of stimulations as anodal, cathodal and sham as a control. The task performed Pre and Post tDCS stimulation, was to point as fast and as precise as possible with the big toe to targets having different sizes (2 and 8 cm; Width) and positioned at different Distances (20 and 60 cm; Distance). An optoelectronic motion capture system was used to collect the kinematics of movement. Result indicates that individuals after receiving anodal stimulation decreased their movement time and increased their movement speed while the opposite happened after receiving a cathodal stimulation. The scarcity of studies in this area invites us to plan a research that aims at the trade-off especially in the clinical settings.

绝大多数人类行为均存在运动速度与准确性之间的权衡关系。本研究采用单盲交叉设计，旨在探究动作控制中的前馈成分：对16名被试施加时长20分钟、强度2mA的经颅直流电刺激（transcranial Direct Current Stimulation, tDCS），刺激位点为辅助运动区（Supplementary Motor Area, SMA），随后测试被试的快速指向动作。实验包含三种随机分配的刺激时段，分别为阳极刺激、阴极刺激与作为对照的伪刺激。在tDCS刺激前后均需执行同一任务：被试用大脚趾以尽可能快且精准的方式指向不同尺寸（宽度为2cm与8cm）、不同距离（距离为20cm与60cm）的目标。本研究采用光电运动捕捉系统采集运动学数据。结果显示，接受阳极刺激的被试运动时长缩短、运动速度提升，而接受阴极刺激的被试则出现相反变化。当前该领域相关研究较为匮乏，因此我们计划开展一项专门针对该权衡关系的研究，尤其聚焦于临床场景中。