Department of Integrative Physiology, Kyorin University School of Medicine, Mitaka City, Tokyo, Japan.
Department of Physical Therapy, School of Rehabilitation Sciences, Health Sciences University of Hokkaido, Tobetsu-cho, Hokkaido, Japan.
J Neurophysiol. 2020 Jul 1;124(1):86-101. doi: 10.1152/jn.00574.2019. Epub 2020 Jun 3.
Motor imagery is known to affect the reacquisition of motor functioning after damage to the central nervous system. However, it remains unclear whether motor imagery influences corticospinal (CST) excitation mediated via cervical premotoneurons, which may be important for functional motor recovery in animals and humans. To investigate this, we examined the spatial facilitation of motor-evoked potentials (MEPs) induced by combined stimulation (CS) of CST and peripheral nerves. Thirty-two healthy volunteers were included and electromyograms from the biceps brachii (BB) were recorded. Transcranial magnetic stimulation (TMS) to motor cortex and electrical stimulation of ulnar nerve at wrist (NERVE) were delivered separately or in combination with 6-15 ms of interstimulus intervals (ISIs). Subjects were instructed to imagine performing an elbow flexion at rest and during tonic BB contraction. During both motor imagery and control tasks, CS (7.5-12 ms of ISIs) facilitated MEPs, compared with the mathematical summation of responses obtained with either only TMS or NERVE ( < 0.01). Interestingly, the CS-induced facilitation was significantly increased by motor imagery compared with control ( < 0.01). Single-motor unit recording also revealed increased facilitation during motor imagery, which was observed in peaks of the peristimulus time histogram 1-2 ms later than the onset latency ( < 0.01). The present findings suggest that motor imagery facilitates oligosynaptic CST excitation of arm motoneurons, mediated by cervical premotoneurons. Thus motor imagery may be a useful tool for activating the premotoneuron systems, which may contribute to motor reacquisition. Imaging movement has positive effects on the reacquisition of motor functions after damage to the central nervous system. This study shows that motor imagery facilitates oligosynaptic corticospinal excitation that is mediated via cervical premotoneurons, which may be important for motor recovery in monkeys and humans. Current findings highlight how this imagery might be a beneficial tool for movement disorders through effects on premotoneuron circuitry.
运动想象已知会影响中枢神经系统损伤后运动功能的重新获得。然而，目前尚不清楚运动想象是否会影响通过颈前运动神经元介导的皮质脊髓（CST）兴奋，这对于动物和人类的功能性运动恢复可能很重要。为了研究这一点，我们检查了 CST 和外周神经联合刺激（CS）诱导的运动诱发电位（MEP）的空间易化。共纳入 32 名健康志愿者，并记录肱二头肌（BB）的肌电图。单独给予经颅磁刺激（TMS）至运动皮层和腕部尺神经电刺激（NERVE），或在 6-15 毫秒的刺激间隔（ISIs）下组合给予。受试者被指示在休息和肱二头肌紧张收缩时想象进行肘部弯曲。在运动想象和对照任务期间，与仅用 TMS 或 NERVE 获得的反应的数学总和相比，CS（7.5-12 ms 的 ISIs）促进了 MEP（<0.01）。有趣的是，与对照相比，运动想象使 CS 诱导的易化显著增加（<0.01）。单运动单位记录还显示，在运动想象期间，易化增加，在刺激后时间直方图的峰中观察到，比起始潜伏期晚 1-2 毫秒（<0.01）。本研究结果表明，运动想象通过颈前运动神经元促进臂运动神经元的少突触 CST 兴奋。因此，运动想象可能是激活前运动神经元系统的有用工具，这可能有助于运动的重新获得。对运动的想象对中枢神经系统损伤后运动功能的重新获得有积极影响。这项研究表明，运动想象促进了通过颈前运动神经元介导的少突触皮质脊髓兴奋，这对于猴子和人类的运动恢复可能很重要。目前的研究结果强调了这种想象如何通过对前运动神经元电路的影响成为运动障碍的有益工具。
