Facilitation of corticospinal excitability in the tibialis anterior muscle during robot-assisted passive stepping in humans
Facilitation of corticospinal excitability in the tibialis anterior muscle during robot-assisted passive stepping in humans
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DOI：
10.1111/j.1460-9568.2009.06795.x
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发表时间：
2009-07-01
影响因子：
3.4
通讯作者：
Nakazawa, Kimitaka
中科院分区：
文献类型：
--
作者：
Kamibayashi, Kiyotaka;Nakajima, Tsuyoshi;Nakazawa, Kimitaka
尽管在正常步行过程中观察到皮质脊髓束对下肢肌肉兴奋性的阶段性调节，但尚不清楚步行引起的传入信息在多大程度上与调节相关。本研究的目的是通过对运动皮层进行经颅磁刺激 (TMS) 和经颅电刺激来测试皮质脊髓对下肢肌肉的兴奋性，同时 13 名健康受试者被动地踩上机器人驱动的步态矫形器。具体来说，为了研究被动迈步过程中负载相关传入输入对皮质脊髓兴奋性的影响，比较了两种被动迈步条件下响应刺激的运动诱发电位（MEP）：跑步机上 40% 体重卸载（地面踏步）和空中 100% 体重卸载（空中踏步）。在股直肌、股二头肌和胫骨前肌 (TA) 中，在任一迈步条件下的整个迈步周期中均未观察到肌电活动。然而，在地面迈步过程中，TMS 诱发的 TA 肌肉在摆动早期和后期以及早期站立阶段的 MEP 明显大于空中迈步过程中观察到的 MEP。经颅电刺激诱发的 MEP 的调制模式与 TMS 诱发的 MEP 的调制模式相似。这些结果表明，与负荷相关的传入输入促进了皮质脊髓对 TA 的兴奋性。因此，这些结果可能与负载相关的传入输入在步态障碍的运动训练期间发挥重要作用的观点一致。
Although phasic modulation of the corticospinal tract excitability to the lower limb muscles has been observed during normal walking, it is unclear to what extent afferent information induced by walking is related to the modulation. The purpose of this study was to test the corticospinal excitability to the lower limb muscles by using transcranial magnetic stimulation (TMS) and transcranial electrical stimulation of the motor cortex while 13 healthy subjects passively stepped in a robotic driven-gait orthosis. Specifically, to investigate the effect of load-related afferent inputs on the corticospinal excitability during passive stepping, motor evoked potentials (MEPs) in response to the stimulation were compared between two passive stepping conditions: 40% body weight unloading on a treadmill (ground stepping) and 100% body weight unloading in the air (air stepping). In the rectus femoris, biceps femoris and tibialis anterior (TA) muscles, electromyographic activity was not observed throughout the step cycle in either stepping condition. However, the TMS-evoked MEPs of the TA muscle at the early- and late-swing phases as well as at the early-stance phase during ground stepping were significantly larger than those observed during air stepping. The modulation pattern of the transcranial electrical stimulation-evoked MEPs was similar to that of the TMS-evoked MEPs. These results suggest that corticospinal excitability to the TA is facilitated by load-related afferent inputs. Thus, these results might be consistent with the notion that load-related afferent inputs play a significant role during locomotor training for gait disorders.