Related Experiment Video
Updated: May 31, 2026
The "Motor" in Implicit Motor Sequence Learning: A Foot-stepping Serial Reaction Time Task
Published on: May 3, 2018
Lack of association between corticospinal excitability changes during motor imagery and explicit sequence learning
Yuma Takenaka1, Kentaro Maeda2, Miyu Yamada2
1Graduate Course of Health and Social Work, Kanagawa University of Human Services, 1-10-1 Heisei-cho, Yokosuka, Kanagawa, Japan; Japan Society for the Promotion of Science, Japan.
Background:
Motor imagery (MI) improves motor performance, but standardized objective quality evaluation methods are lacking. The relationship between MI quality and actual performance improvements also remains unclear.
Purpose:
We investigated whether corticospinal excitability measured using motor evoked potentials (MEPs) during MI could serve as an objective quality index of MI using an explicit serial reaction time task (SRTT). Specifically, we examined whether changes in MEPs correlated with performance improvements following MI.
Methods:
Experiment 1 (n = 10) validated the SRTT and practice volume. Participants performed physical practice under both sequential and random conditions. Experiment 2 (n = 18) used only the sequence conditions. We measured reaction time (RT) during physical execution and MEPs from the first dorsal interosseous muscle during task MI, both before and after MI practice.
Results:
In Experiment 1, RT decreased only in sequential condition (padj<0.001). In Experiment 2, RT significantly improved following MI practice (padj<0.001). Although MEP amplitudes during MI were significantly larger than those at rest both before and after practice (padj<0.001), no significant changes in MEPs were observed between the pre- and post-practice assessments (padj=0.054). Furthermore, no significant correlations were found between changes in RT and MEP-related variables (r < 0.411, p > 0.163).
Conclusion:
These results suggest that MEPs may not be a useful index of MI quality in the context of explicit SRTT.
