Yatsu Hoken Hospital, 4-6-16 Yatsu, Narashino-shi, Chiba, 275-0026, Japan.
Tokyo Bay Rehabilitation Hospital, 4-1-1 Yatsu, Narashino-shi, Chiba, 275-0026, Japan.
Neurol Sci. 2021 Sep;42(9):3813-3820. doi: 10.1007/s10072-021-05054-z. Epub 2021 Jan 19.
Motor imagery (MI) is known to improve motor function through enhancement of motor cortex activity. Spinal reciprocal inhibition (RI) is modulated by motor cortex activity, and, therefore, MI may change RI. The aim of this study was to examine the changes in RI during MI involving the lower extremity. Spinal RI was measured from the tibialis anterior (TA) to the soleus (SOL). Eleven healthy adults participated in experiment 1. All participants performed the following three conditions, and RI was assessed during each condition: (1) resting condition; (2) MI of ankle dorsiflexion condition (MI-DF); and (3) MI of ankle plantarflexion condition (MI-PF). Twelve healthy adults participated in experiment 2. All participants performed the following two conditions, and RI was assessed before and after MI practice for 10 min: (1) resting condition and (2) MI-DF. The interval between the conditioning and test stimulus (inter-stimulus interval; ISI) was set at 0, 1, 2, or 3 ms and 20 ms. In experiment 1, RI during MI-PF was significantly decreased compared with that during resting with both stimulus intervals. RI during MI-DF showed no significant change compared with that during resting with both ISIs. In experiment 2, the difference between the rest condition and the MI-DF condition after the MI task with ISI of 20 ms was significantly higher than before the MI task. Our findings suggest that real-time changes in RI during MI involving the lower extremity may vary depending on the direction of motion and MI practice.
运动想象（MI）被认为可以通过增强运动皮层活动来改善运动功能。脊髓交互抑制（RI）受运动皮层活动的调节，因此，MI 可能会改变 RI。本研究旨在探讨下肢 MI 过程中 RI 的变化。通过胫骨前肌（TA）和比目鱼肌（SOL）测量脊髓 RI。11 名健康成年人参加了实验 1。所有参与者均进行以下三种状态，在每种状态下评估 RI：（1）休息状态；（2）踝关节背屈 MI 状态（MI-DF）；（3）踝关节跖屈 MI 状态（MI-PF）。12 名健康成年人参加了实验 2。所有参与者均进行以下两种状态，在 10 分钟的 MI 练习前后评估 RI：（1）休息状态和（2）MI-DF。刺激间隔（ISI）设为 0、1、2 或 3ms 和 20ms。在实验 1 中，与休息状态相比，MI-PF 期间的 RI 在两种刺激间隔下均显著降低。与休息状态相比，MI-DF 期间的 RI 没有明显变化，两种 ISI 均如此。在实验 2 中，20ms ISI 下 MI 任务后的休息条件与 MI-DF 条件之间的差异明显高于 MI 任务前。我们的研究结果表明，下肢 MI 过程中 RI 的实时变化可能因运动方向和 MI 练习而异。
