Schoenfeld Marleen J, Grigoras Ioana-Florentina, Stagg Charlotte J, Zich Catharina
Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, United Kingdom.
Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
Front Hum Neurosci. 2021 Nov 16;15:755748. doi: 10.3389/fnhum.2021.755748. eCollection 2021.
Many tasks require the skilled interaction of both hands, such as eating with knife and fork or keyboard typing. However, our understanding of the behavioural and neurophysiological mechanisms underpinning bimanual motor learning is still sparse. Here, we aimed to address this by first characterising learning-related changes of different levels of bimanual interaction and second investigating how beta tACS modulates these learning-related changes. To explore early bimanual motor learning, we designed a novel bimanual motor learning task. In the task, a force grip device held in each hand (controlling - and -axis separately) was used to move a cursor along a path of streets at different angles (0°, 22.5°, 45°, 67.5°, and 90°). Each street corresponded to specific force ratios between hands, which resulted in different levels of hand interaction, i.e., unimanual (, i.e., 0°, 90°), bimanual with equal force ( , 45°), and bimanual with unequal force ( 22.5°, 67.5°). In experiment 1, 40 healthy participants performed the task for 45 min with a minimum of 100 trials. We found that the novel task induced improvements in movement time and error, with no trade-off between movement time and error, and with distinct patterns for the three levels of bimanual interaction. In experiment 2, we performed a between-subjects, double-blind study in 54 healthy participants to explore the effect of phase synchrony between both sensorimotor cortices using tACS at the individual's beta peak frequency. The individual's beta peak frequency was quantified using electroencephalography. 20 min of 2 mA peak-to-peak amplitude tACS was applied during task performance (40 min). Participants either received in-phase (0° phase shift), out-of-phase (90° phase shift), or sham (3 s of stimulation) tACS. We replicated the behavioural results of experiment 1, however, beta tACS did not modulate motor learning. Overall, the novel bimanual motor task allows to characterise bimanual motor learning with different levels of bimanual interaction. This should pave the way for future neuroimaging studies to further investigate the underlying mechanism of bimanual motor learning.
许多任务都需要双手熟练配合，比如用刀叉吃饭或键盘打字。然而，我们对支撑双手运动学习的行为和神经生理机制的了解仍然有限。在此，我们旨在通过首先描述不同水平双手交互中与学习相关的变化，其次研究β经颅交流电刺激（tACS）如何调节这些与学习相关的变化来解决这一问题。为了探究早期双手运动学习，我们设计了一项新颖的双手运动学习任务。在该任务中，参与者双手各持一个力握装置（分别控制x轴和y轴），用于沿不同角度（0°、22.5°、45°、67.5°和90°）的街道路径移动光标。每条街道对应双手之间特定的力比，这导致了不同水平的手部交互，即单手（即0°、90°）、等力双手（45°）和不等力双手（22.5°、67.5°）。在实验1中，40名健康参与者进行该任务45分钟，最少进行100次试验。我们发现，这项新任务使运动时间和误差得到改善，运动时间和误差之间没有权衡，并且三种水平的双手交互有不同的模式。在实验2中，我们对54名健康参与者进行了一项双盲组间研究，以探索使用个体β峰值频率的tACS对两个感觉运动皮层之间相位同步的影响。使用脑电图对个体的β峰值频率进行量化。在任务执行期间（40分钟）施加20分钟峰峰值幅度为2 mA的tACS。参与者分别接受同相（0°相移）、异相（90°相移）或假刺激（3秒刺激）tACS。我们重复了实验1的行为结果，然而，β tACS并未调节运动学习。总体而言，这项新颖的双手运动任务能够描述不同水平双手交互的双手运动学习。这应该为未来的神经影像学研究进一步探究双手运动学习的潜在机制铺平道路。
