Context-dependent modulation of rhythmic upper and lower limb movement in humans

本研究探讨了在同时进行手臂和腿部踏板时，手臂和腿部之间的肢体间耦合在多大程度上取决于运动环境的调节，这已经被用来研究人类中枢模式发生器的功能。我们发现：(1)腿部节奏的视觉反馈显著改变了手臂踏板的节奏，(2)只有当受试者先以恒定的节奏进行手臂踏板，然后再进行腿部踏板时，手臂踏板的节奏才显著降低，(3)手臂肌肉中皮肤反射的大小显著地取决于手臂肌肉的激活程度和腿部踏板的节奏。这些发现表明，有节奏的手臂和腿的运动受到CPG的调节，并且这些运动相互作用取决于运动的背景和运动的生物力学约束。

The present study investigated to what extent interlimb coupling between the arm and leg are modulated depending on the context of movement while performing simultaneous arm and leg pedaling which has been used to investigate the function of central pattern generator (CPG) in humans. We found that (1) the cadence of arm pedaling was significantly changed by visual feedback on the leg cadence, (2) the cadence of arm pedaling was significantly decreased only when the subject first performed arm pedaling at a constant cadence then performed leg pedaling, (3) magnitude of cutaneous reflexes in the arm muscles was significantly modulated depending on the activation level of the arm muscles and the cadence of leg pedaling. These finding suggest that rhythmic arm and leg movement is regulated by CPG, and that these interact depending on the context of movement and biomechanical constrains of movement.