Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts.
Neuroscience and Behavior Program, University of Massachusetts, Amherst, Massachusetts.
J Neurophysiol. 2019 Sep 1;122(3):1097-1109. doi: 10.1152/jn.00865.2018. Epub 2019 Jul 24.
When walking on a split-belt treadmill where one belt moves faster than the other, the nervous system consistently attempts to maintain symmetry between legs, quantified as deviation from double support time or step length symmetry. It is known that the cerebellum plays a critical role in locomotor adaptation. Less is known about the role of corticospinal drive in maintaining this type of proprioceptive-driven locomotor adaptation. The objective of this study was to examine the functional role of oscillatory drive in relation to changes in spatiotemporal gait parameters during split-belt walking adaptation. Eighteen healthy participants adapted and deadapted on a split-belt treadmill; 13 out of 18 participants repeated the paradigm two more times to examine the effects of reexposure. Coherence analysis was used to quantify the coupling between electromyography (EMG) from the proximal (TA) and distal tibialis anterior (TA) muscle during the swing phase of walking. EMG-EMG coherence was examined within the alpha (8-15 Hz), beta (15-30 Hz), and gamma (30-45 Hz) frequencies. Our results showed that ) beta- and gamma-band coherence (markers of corticospinal drive) increased during early split-belt walking compared with baseline walking in the slow leg, ) beta-band coherence decreased from early to late split-belt adaptation in the fast leg, ) alpha-, beta-, and gamma-band coherence decreased from first to third split-belt exposure in the fast leg, and ) there was a relationship between higher beta coherence in the slow leg TA and smaller double support asymmetry. Our results suggest that corticospinal drive may play a functional role in the temporal control of split-belt walking adaptation. This is the first study to examine the functional role of intramuscular coherence in relation to changes in spatiotemporal gait parameters during split-belt walking adaptation. We found that the corticospinal drive measured by intramuscular coherence in tibialis anterior changes with adaptation and that the corticospinal drive is related to temporal but not spatial parameters. This study may give insight as to the specific role of the motor cortex during gait.
当在一个一个带速不同的分带跑步机上行走时，神经系统会不断尝试保持腿部的对称性，这可以通过双支撑时间或步长对称性的偏差来量化。已知小脑在运动适应中起着关键作用。但是，对于皮质脊髓驱动在维持这种本体感受驱动的运动适应中的作用知之甚少。本研究的目的是检查振荡驱动在分带步行适应过程中时空步态参数变化中的功能作用。18 名健康参与者在分带跑步机上进行了适应和再适应；其中 13 名参与者重复了两次该范式，以检查再暴露的影响。相干性分析用于量化在行走摆动阶段近端（TA）和远端胫骨前肌（TA）肌肉的肌电图（EMG）之间的耦合。在 alpha（8-15 Hz）、beta（15-30 Hz）和 gamma（30-45 Hz）频率范围内检查了 EMG-EMG 相干性。我们的结果表明，) 在慢腿的分带行走早期与基线行走相比，beta 和 gamma 波段相干性（皮质脊髓驱动的标志物）增加，) 在快腿的分带适应早期到晚期，beta 波段相干性降低，) 在快腿的第一次到第三次分带暴露中，alpha、beta 和 gamma 波段相干性降低，) 在慢腿 TA 中较高的 beta 相干性与较小的双支撑不对称性之间存在关系。我们的结果表明，皮质脊髓驱动可能在分带行走适应的时间控制中发挥功能作用。这是第一项研究，研究了在分带步行适应过程中，肌内相干性与时空步态参数变化之间的功能关系。我们发现，前胫骨的肌内相干性测量的皮质脊髓驱动随适应而变化，并且皮质脊髓驱动与时间参数有关，而与空间参数无关。这项研究可能为运动皮质在步态中的特定作用提供一些启示。
