Arm swing movement is coordinated with movement of the legs during walking, where the frequency of coordination depends on walking speed. At typical speeds, arm and leg movements, respectively, are frequency locked in a 1:1 ratio but at slow speeds this changes to a 2:1 ratio. It is unknown if the changes in interlimb ratio that accompany slow walking speeds alters regulation of somatosensory feedback. To probe the neural interactions between the arms and legs, somatosensory linkages in the form of interlimb cutaneous reflexes were examined. It was hypothesized that different interlimb frequencies and walking speeds would result in changes in the modulation of cutaneous reflexes between the arms and legs. To test this hypothesis, participants walked in four combinations of walking speed (typical, slow) and interlimb coordination (1:1, and 2:1), while cutaneous reflexes and background muscle activity were evaluated with stimulation applied to the superficial peroneal nerve at the ankle and superficial radial nerve at the wrist. Results show main effects of interlimb coordination and walking speed on cutaneous reflex modulation, effects are largest in the swing phase, and a directional coupling was observed, where changes in the frequency of arm movements had a greater effect on muscle activity in the legs compared to the reverse. Task-dependent modulation was also revealed from stimulation at local and remote sources. Understanding the underlying neural mechanisms for the organization of rhythmic arm movement, and its coordination with the legs in healthy participants, can give insight into pathological walking, and will facilitate the development of effective strategies for the rehabilitation of walking.

中文翻译：

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以慢速行走改变手臂和腿部之间的耦合会改变体感反馈的调节。

手臂摆动运动与步行过程中腿部运动相协调，协调的频率取决于步行速度。在典型速度下，手臂和腿部的运动分别以1：1的比率锁定频率，但在慢速下会变为2：1的比率。步行速度慢时的肢体比率变化是否会改变体感反馈的调节，这一点尚不清楚。为了探测手臂和腿之间的神经相互作用，检查了肢体皮肤反射形式的体感联系。据推测，不同的肢体频率和步行速度将导致手臂和腿部之间皮肤反射调制的变化。为了验证这一假设，参与者采用了步行速度（典型，慢速）和肢体协调（1：1和2：1）的四种组合，同时通过刺激脚踝浅腓神经和腕浅radial神经来评估皮肤反射和背景肌肉活动。结果显示，肢体协调和步行速度对皮肤反射调制的主要影响，在挥杆阶段的影响最大，并且观察到了方向性耦合，与之相比，手臂运动频率的变化对腿部肌肉活动的影响更大。相反。从本地和远程源的刺激还揭示了任务相关的调制。了解有节奏的手臂运动组织的基本神经机制，以及健康参与者与腿部的协调关系，可以深入了解病理性行走，