Yamaguchi Tomofumi, Svane Christian, Forman Christian Riis, Beck Mikkel Malling, Geertsen Svend Sparre, Lundbye-Jensen Jesper, Nielsen Jens Bo
Department of Neuroscience, University of Copenhagen, 2200 Copenhagen, Denmark.
Department of Physical Therapy, Faculty of Health Science, Juntendo University, Tokyo 113-8421, Japan.
Cereb Cortex Commun. 2020 Aug 6;1(1):tgaa047. doi: 10.1093/texcom/tgaa047. eCollection 2020.
Consolidation leading to retention of motor memory following motor practice involves activity-dependent plastic processes in the corticospinal system. To investigate whether beta-band transcranial alternating current stimulation (tACS) applied immediately following skill acquisition can enhance ongoing consolidation processes and thereby motor skill retention 20 adults participated in a randomized, double-blinded, sham-controlled study. Participants received tACS at peak beta-band corticomuscular coherence (CMC) frequency or sham tACS for 10 min following practice of a visuomotor ankle dorsiflexion task. Performance was measured as the average percentage time on target. Electroencephalograhy (EMG) was measured at Cz and EMG from the right tibialis anterior muscle. CMC and intramuscular coherence (IMC) were estimated during 2-min tonic dorsiflexion. Motor skill retention was tested 1 and 7 days after motor practice. From the end of motor practice to the retention tests, motor performance improved more in the tACS group compared with the sham tACS group after 1 ( = 0.05) and 7 days ( < 0.001). At both retention tests, beta-band IMC increased in the tACS group compared with post-tACS. Beta-band CMC increased in the tACS group at retention day 1 compared with post-tACS. Changes in CMC but not IMC were correlated with performance 1 and 7 days following practice. This study shows that tACS applied at beta-band CMC frequency improves consolidation following visuomotor practice and increases beta-band CMC and IMC. We propose that oscillatory beta activity in the corticospinal system may facilitate consolidation of the motor skill.
运动练习后导致运动记忆保留的巩固过程涉及皮质脊髓系统中依赖活动的可塑性过程。为了研究在技能习得后立即施加的β波段经颅交流电刺激（tACS）是否能增强正在进行的巩固过程，从而提高运动技能保留率，20名成年人参与了一项随机、双盲、假刺激对照研究。参与者在进行视觉运动踝关节背屈任务练习后，以β波段皮质肌肉相干性（CMC）峰值频率接受tACS或假tACS刺激10分钟。以目标上的平均时间百分比来衡量表现。在Cz点测量脑电图（EEG），并测量右胫前肌的肌电图（EMG）。在2分钟的强直性背屈过程中估计CMC和肌内相干性（IMC）。在运动练习后1天和7天测试运动技能保留情况。从运动练习结束到保留测试，tACS组在1天（P = 0.05）和7天（P < 0.001）后的运动表现比假tACS组改善得更多。在两次保留测试中，与tACS后相比，tACS组的β波段IMC增加。与tACS后相比，tACS组在保留第1天的β波段CMC增加。练习后1天和7天，CMC的变化而非IMC的变化与表现相关。这项研究表明，以β波段CMC频率施加的tACS可改善视觉运动练习后的巩固过程，并增加β波段CMC和IMC。我们提出，皮质脊髓系统中的振荡β活动可能有助于运动技能的巩固。
