Department of Rehabilitation, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, Kurashiki, Okayama, Japan.
Rehabilitation Center, Kawasaki Medical School Hospital, Kurashiki, Okayama, Japan.
PLoS One. 2020 Jan 28;15(1):e0228389. doi: 10.1371/journal.pone.0228389. eCollection 2020.
Transcranial magnetic stimulation (TMS) has been widely utilized to noninvasively explore the motor system during the observation of human movement. However, few studies have characterized motor cortex activity during periodic gait observation. Thus, this study examined the effects of an observer's visual experience and/or intention to imitate on corticospinal excitability during the observation of another's gait. Twenty-six healthy volunteers were included in this study and allocated to two different groups. Participants in the visual experience group had formal experience with gait observation (physical therapist training), while those in the control group did not. Motor-evoked potentials induced by TMS in the tibialis anterior and soleus muscles were measured as surrogates of corticospinal excitability. Participants were seated and, while resting, they observed a demonstrator's gait or observed it with the intention to subsequently reproduce it. Compared with the resting state, cyclic gait observation led to significant corticospinal facilitation in the tibialis anterior and soleus muscles. However, this pattern of corticospinal facilitation in the measured muscles was not coupled to the pattern of crural muscle activity during actual gait and was independent of the step cycle. This motor cortex facilitation effect during gait observation was enhanced by the observer's visual experience in a manner that was not step cycle-dependent, while the observer's intent to imitate did not affect corticospinal excitatory input to either muscle. In addition, visual experience did not modulate corticospinal excitability in gait-related crural muscles. Our findings indicate that motor cortex activity during gait observation is not in line with the timing of muscle activity during gait execution and is modulated by an individual's gait observation experience. These results suggest that visual experience acquired from repetitive gait observation may facilitate the motor system's control on bipedal walking, but may not promote the learning of muscle activity patterns.
经颅磁刺激（TMS）已被广泛应用于观察人类运动时对运动系统进行非侵入性研究。然而，目前很少有研究对周期性步态观察过程中的运动皮层活动进行描述。因此，本研究旨在探讨观察者的视觉经验和/或模仿意图对观察他人步态时皮质脊髓兴奋性的影响。本研究共纳入 26 名健康志愿者，并将其分为两组。视觉经验组的参与者接受过步态观察方面的正规培训（物理治疗师培训），而对照组的参与者则没有。通过 TMS 刺激胫骨前肌和比目鱼肌来测量运动诱发电位，作为皮质脊髓兴奋性的替代指标。参与者保持坐姿，在休息状态下观察演示者的步态，或者观察演示者的步态，意图随后模仿演示者的步态。与休息状态相比，周期性步态观察会导致胫骨前肌和比目鱼肌的皮质脊髓兴奋性显著增强。然而，这种测量肌肉的皮质脊髓兴奋模式与实际步态中的小腿肌肉活动模式并不相关，且不依赖于步周期。观察者的视觉经验以一种不依赖于步周期的方式增强了观察步态时运动皮层的这种易化效应，而观察者的模仿意图则不会影响到两块肌肉的皮质脊髓兴奋性输入。此外，视觉经验并没有调节与步态相关的小腿肌肉的皮质脊髓兴奋性。我们的研究结果表明，观察步态时运动皮层的活动与步态执行时肌肉活动的时间不一致，并且受到个体步态观察经验的调节。这些结果表明，从重复性步态观察中获得的视觉经验可能有助于运动系统对双足行走的控制，但可能不会促进肌肉活动模式的学习。
