左侧背外侧前额叶在程序性运动学习中的作用

程序性运动学习包括序列学习和随机学习。神经影像学研究表明背外侧前额叶皮层(DLPFC)和初级运动皮层(M1)在程序性运动学习中发挥重要作用,但DLPFC和M1之间的联通性及其与不同程序性运动学习的关系尚不明确。本研究采用连续反应时间任务,结合经颅磁刺激(TMS)方法,探讨左侧DLPFC到M1的联通性在不同程序性运动学习中的差异。实验1采用两连发TMS探测DLPFC到M1的最佳投射时间点;实验2,被试分为2组,分别进行序列学习和随机学习,在学习前、后采集行为学数据,以及M1的运动诱发电位和DLPFC-M1联通性的电生理学数据。行为学结果发现序列学习组的学习效果更佳;电生理学结果发现,两组被试学习前、后M1的运动诱发电位均未发生改变;在最佳时间投射点、适当刺激强度下,序列学习组DLPFC-M1联通性发生改变,且与学习成绩相关,而随机学习组没有改变。结果说明DLPFC到M1的联通性增强可能是序列学习成绩更佳的重要原因,这一结果从电生理角度为DLPFC在运动学习中的作用提供了重要证据。

Functional role of the left dorsolateral prefrontal cortex in procedural motor learning

Procedural motor learning includes sequence learning and random learning. Neuroimaging studies have shown that the dorsolateral prefrontal cortex (DLPFC) and primary motor cortex (M1) play significant roles in procedural motor learning; however, the connectivity between the DLPFC and M1 and its relationship with different procedural motor learning are still unclear. In this study, the serial response time task (SRTT) and transcranial magnetic stimulation (TMS) were used to explore the differences in left DLPFC-M1 connectivity between the different types of procedural motor learning. In experiment 1, dual-site paired-pulse TMS was used to detect the optimal interval from the DLPFC to the M1. In experiment 2, the participants were divided into two groups that underwent sequence learning or random learning. Behavioral data, motor evoked potentials from the M1 and electrophysiological data of DLPFC-M1 connectivity were assessed before and after learning. The behavioral results showed that the learning effect of the sequence learning group was better. The electrophysiological results showed that motor evoked potentials from the M1 were the same before and after learning in both groups. At the optimal interval and appropriate stimulation intensity, the DLPFC-M1 connectivity in the sequence learning group was changed, and it was related to learning performance; however that in the random learning group was not significantly changed. The results suggest that enhanced connectivity between the DLPFC and M1 may be an important explanation for the better performance in sequence learning. The results provide robust electrophysiological evidence for the role of DLPFC in motor learning.