Abstract

Previous research has revealed rapid feedback mediated responses in one arm to mechanical perturbations applied to the other arm during shared bimanual tasks. We now ask whether these interlimb responses are expressed symmetrically. We tested this question in a virtual reality environment: a cursor representing each hand was used to ‘pick up’ each end of a virtual bar and place it into a target trough. Near the onset of occasional, unpredictable trials, one arm was perturbed. Regardless of which arm was perturbed, ipsilateral responses were significant during the perturbation. However, responses in the arm contralateral to the perturbation were asymmetric. While the non-dominant arm showed a significant kinematic response to correct the bar orientation when the dominant arm was mechanically perturbed, the dominant arm did not respond when the non-dominant arm was perturbed. We also saw an asymmetric response in early EMG activity, in which only the non-dominant anterior deltoid showed a significant reflex response within 100 milliseconds of perturbation onset in response to dominant arm. This response was consistent with correcting the bar position, but not with correcting its orientation. We conclude that responses to perturbations during bilateral movements are expressed asymmetrically, such that non-dominant arm responses to perturbations to the dominant arm are stronger than dominant arm responses to non-dominant arm perturbations.

摘要

先前的研究表明，在共享的双向任务中，一只手臂对施加于另一只手臂的机械扰动的快速反馈介导的反应。现在，我们问这些交错响应是否对称表达。我们在虚拟现实环境中测试了这个问题：使用代表每只手的光标来“拾取”虚拟条的两端并将其放入目标槽中。在偶然的，无法预料的审判临近开始时，一只手臂受到了干扰。无论哪条手臂被打扰，在打扰过程中同侧反应都很明显。但是，手臂对侧扰动的反应是不对称的。当非机械臂受到机械干扰时，非机械臂表现出显着的运动学响应，以纠正杆的方向，当非支配臂受到干扰时，支配臂没有反应。我们还看到了早期EMG活动中的不对称反应，其中仅非显性前三角肌在对支配臂的反应发生摄动的100毫秒内显示出明显的反射反应。此响应与纠正钢筋位置一致，但与纠正其方向不一致。我们得出的结论是，在双边运动过程中对扰动的响应是不对称表达的，因此，对支配臂的扰动，非支配臂的响应要强于对非支配臂的扰动的支配臂。其中仅非优势前三角肌在对支配臂的反应发生扰动开始后的100毫秒内显示出明显的反射反应。此响应与纠正钢筋位置一致，但与纠正其方向不一致。我们得出的结论是，在双边运动过程中对扰动的响应是不对称表达的，因此，对支配臂的扰动，非支配臂的响应要强于对非支配臂的扰动的支配臂。其中仅非优势前三角肌在对支配臂的反应发生扰动开始后的100毫秒内显示出明显的反射反应。此响应与纠正钢筋位置一致，但与纠正其方向不一致。我们得出的结论是，在双边运动过程中对扰动的响应是不对称表达的，因此，对支配臂的扰动，非支配臂的响应要强于对非支配臂的扰动的支配臂。