Firouzi Mahyar, Baetens Kris, Duta Catalina, Baeken Chris, Van Overwalle Frank, Swinnen Eva, Deroost Natacha
Brain, Body and Cognition Research Group, Faculty of Psychology and Educational Sciences, Vrije Universiteit Brussel, Elsene, Belgium.
Rehabilitation Research Group, Department of Physiotherapy, Human Physiology and Anatomy, Vrije Universiteit Brussel, Jette, Belgium.
Front Neurosci. 2024 Dec 6;18:1433867. doi: 10.3389/fnins.2024.1433867. eCollection 2024.
Implicit motor sequence learning (IMSL) is a cognitive function that allows us to execute multiple movements in a specific sequential order and plays a crucial role in our daily functional activities. Although the role of the basal ganglia network in IMSL is well-established, the exact involvement of the cerebellar network is less clear.
Here, we aimed to address this issue by investigating the effects of cerebellar transcranial direct-current stimulation (tDCS) on IMSL.
In this sham-controlled, crossover study in 45 healthy young adults, we used mixed-effects models to analyze sequence-specific (primary outcome) and general learning effects (secondary outcome) in the acquisition (during tDCS), short- (five minutes post-tDCS) and long-term consolidation (one week post-tDCS) phases of IMSL, as measured by the serial reaction time (SRT) task.
Analyses based on response times (RTs) revealed that anodal tDCS over the cerebellum significantly increased sequence-specific learning during acquisition, compared to sham (anodal: = 38.24 ms, sham: = 26.78 ms, = 0.032); did not affect general learning; and significantly slowed overall RTs (anodal: = 362.03 ms, sham: = 356.37 ms, = 0.049). Accuracy-based analyses revealed that anodal tDCS reduced the probability of correct responses occurring in random trials versus sequential trials by 1.17%, = 0.009, whereas sham tDCS had no effect, = 0.999.
Our finding of enhanced sequence-specific learning, but not general learning, suggests that the cerebellar network not only plays a role in error correction processes, but also serves a sequence-specific function within the integrated motor learning network that connects the basal ganglia and cerebellum.
内隐运动序列学习（IMSL）是一种认知功能，它使我们能够按照特定的顺序执行多个动作，并且在我们的日常功能活动中起着至关重要的作用。尽管基底神经节网络在IMSL中的作用已得到充分证实，但小脑网络的确切参与情况尚不清楚。
在此，我们旨在通过研究小脑经颅直流电刺激（tDCS）对IMSL的影响来解决这一问题。
在这项针对45名健康年轻成年人的假对照交叉研究中，我们使用混合效应模型来分析IMSL的习得阶段（tDCS期间）、短期（tDCS后五分钟）和长期巩固阶段（tDCS后一周）的序列特异性（主要结果）和一般学习效应（次要结果），通过序列反应时（SRT）任务进行测量。
基于反应时间（RTs）的分析表明，与假刺激相比，小脑阳极tDCS在习得期间显著增加了序列特异性学习（阳极： = 38.24毫秒，假刺激： = 26.78毫秒， = 0.032）；不影响一般学习；并且显著减慢了总体RTs（阳极： = 362.03毫秒，假刺激： = 356.37毫秒， = 0.049）。基于准确性的分析表明，阳极tDCS使随机试验与顺序试验中正确反应发生的概率降低了1.17%， = 0.009，而假刺激tDCS没有效果， = 0.999。
我们发现序列特异性学习增强但一般学习未增强，这表明小脑网络不仅在错误校正过程中起作用，而且在连接基底神经节和小脑的整合运动学习网络中发挥序列特异性功能。
