Shaping appropriate locomotive motor output through interlimb neural pathway within spinal cord in humans
Shaping appropriate locomotive motor output through interlimb neural pathway within spinal cord in humans
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DOI：
10.1152/jn.00020.2008
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发表时间：
2008-06-01
影响因子：
2.5
通讯作者：
Nakazawa, Kimitaka
中科院分区：
文献类型：
--
作者：
Kawashima, Noritaka;Nozaki, Daichi;Nakazawa, Kimitaka
支持上肢运动对人类产生机车电机输出的贡献的直接证据仍然有限。在这里，我们的目的是研究上肢运动对脊髓损伤（SCI）患者下肢运动样肌肉活动的影响。通过施加被动运动样的腿部运动，所有颈椎不全（n = 7）和胸椎完全性脊髓损伤受试者（n = 5）在瘫痪的比目鱼肌中表现出运动样的肌肉活动。胸椎完全性脊髓损伤受试者的上肢运动不影响肌肉活动的肌电图模式。这是很自然的，因为在这些受试者中，控制上肢和下肢的脊髓区域之间的神经连接完全丧失了。另一方面，在颈椎不完全性脊髓损伤受试者中，这些神经连接至少部分保留，运动样肌肉活动明显受到被动上肢运动的影响。具体而言，上肢运动普遍增加了后摆阶段的比目鱼肌肌电活动，这与正常步态的站立阶段相对应。尽管一些受试者在施加手臂运动时表现出肌电信号的减弱，但这仍然与运动类电机输出相一致，因为肌电信号的减弱发生在与摆动相对应的向前摆动阶段。本研究结果表明，上肢运动诱导的神经信号不仅有助于增强，而且可能通过肢间神经通路塑造下肢机车电机输出。这种上肢和下肢运动之间的神经相互作用可能是人类两足运动的潜在神经机制。
Direct evidence supporting the contribution of upper limb motion on the generation of locomotive motor output in humans is still limited. Here, we aimed to examine the effect of upper limb motion on locomotor-like muscle activities in the lower limb in persons with spinal cord injury (SCI). By imposing passive locomotion-like leg movements, all cervical incomplete (n = 7) and thoracic complete SCI subjects (n = 5) exhibited locomotor-like muscle activity in their paralyzed soleus muscles. Upper limb movements in thoracic complete SCI subjects did not affect the electromyographic (EMG) pattern of the muscle activities. This is quite natural since neural connections in the spinal cord between regions controlling upper and lower limbs were completely lost in these subjects. On the other hand, in cervical incomplete SCI subjects, in whom such neural connections were at least partially preserved, the locomotor-like muscle activity was significantly affected by passively imposed upper limb movements. Specifically, the upper limb movements generally increased the soleus EMG activity during the backward swing phase, which corresponds to the stance phase in normal gait. Although some subjects showed a reduction of the EMG magnitude when arm motion was imposed, this was still consistent with locomotor-like motor output because the reduction of the EMG occurred during the forward swing phase corresponding to the swing phase. The present results indicate that the neural signal induced by the upper limb movements contributes not merely to enhance but also to shape the lower limb locomotive motor output, possibly through interlimb neural pathways. Such neural interaction between upper and lower limb motions could be an underlying neural mechanism of human bipedal locomotion.