Abstract

Considerable evidence exists related to the behavioral outcomes of motor imagery-based training (MI). Comparatively, there is a relative gap in the literature on how corticospinal excitability, a precursor for experience-dependent plasticity, changes over the course of an MI session, and more specifically if there is an effect of varying the duration of the blocks in which MI is performed. As such, we probed corticospinal excitability during MI, whereby the duration of MI blocks within the session were manipulated yet total exposure to MI was kept constant. Participants performed a total of 24 min of MI of common motor tasks in blocks of 2, 4 or 6 min. Transcranial magnetic stimulation was used to assess corticospinal excitability throughout MI performance. All groups demonstrated increased corticospinal excitability over the session. Owing to a decrease in corticospinal excitability when engaging in 6 min blocks and the variability noted when engaging in 2 min blocks, findings suggest that MI performed in 4 min blocks may be preferable for the generation and maintenance of corticospinal excitability, at least relative to 2 and 6 min blocks. Overall, our findings provide physiological evidence that informs the structure of MI training sessions to optimize their effectiveness.

摘要

大量证据与基于运动意象的训练 (MI) 的行为结果有关。相比之下，关于皮质脊髓兴奋性（经验依赖性可塑性的前体）如何在 MI 会话过程中发生变化的文献中存在相对空白，更具体地说，是否存在改变 MI 的阻滞持续时间的影响被执行。因此，我们在 MI 期间探测了皮质脊髓兴奋性，从而操纵了会话中 MI 块的持续时间，但总暴露于 MI 保持不变。参与者在 2、4 或 6 分钟的时间内完成了总共 24 分钟的常见运动任务 MI。经颅磁刺激用于评估整个 MI 表现的皮质脊髓兴奋性。所有组都表现出在会议期间增加的皮质脊髓兴奋性。由于参与 6 分钟阻滞时皮质脊髓兴奋性降低以及参与 2 分钟阻滞时注意到的可变性，研究结果表明，在 4 分钟阻滞中进行的 MI 可能更适合产生和维持皮质脊髓兴奋性，至少相对于 2和 6 分钟块。总体而言，我们的研究结果提供了生理证据，可以告知 MI 培训课程的结构以优化其有效性。