Inter‐limb coordination is achieved through multiple levels of motor control based on intrinsic‐muscle and extrinsic‐visual coordinates. Online visual feedback affects which of these coordinates is dominant, and visual perception is involved in the switching of motor coordination across the two hands; however, it remains unclear whether there is any role for attention in inter‐limb coordination. Therefore, we evaluated the effects of attention on the dominance of intrinsic‐muscle and extrinsic‐visual coordinates by investigating inter‐limb interference in the right or left hand during bimanual reaching movements, as induced by visual perturbations. We first showed an effect of differences in online visual feedback on bimanual coordination (Experiment 1). We then revealed that attention to visual cursors that directly affected the hand movement led to the dominance of the intrinsic‐muscle coordinates, which synchronized homologous muscle activities. In contrast, attention to an integrated visual object controlled by bilateral hand movements was associated with a preference for extrinsic‐visual coordinates to synchronize bilateral movement directions (Experiment 2). Thus, attention‐dependent switching between intrinsic‐muscle and extrinsic‐visual coordinates was observed during bimanual movements; extrinsic‐visual coordinates may enable goal‐directed bimanual movements at least for particular task requirements.

中文翻译：

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双手运动期间内在肌肉和外在视觉坐标之间的注意力依赖切换

通过基于内在肌肉和外在视觉坐标的多级运动控制，可以实现跨肢协调。在线视觉反馈会影响这些坐标中的哪一个占主导地位，并且视觉感知涉及到两只手的运动协调的切换。然而，目前尚不清楚在跨肢协调中是否有任何注意的作用。因此，我们通过调查视觉扰动引起的双手伸手运动中左右手的肢间干扰，评估了注意力对固有肌肉和外在视觉坐标的支配性的影响。我们首先显示了在线视觉反馈中的差异对双手协调的影响（实验1）。然后我们发现，对直接影响手部动作的视觉光标的注意导致了固有肌肉坐标的支配地位，从而使同源肌肉活动同步化。相反，对由双边手部运动控制的综合视觉对象的关注与偏爱外部视觉坐标以同步双边运动方向的偏好相关（实验2）。因此，在双手运动过程中观察到内在肌肉坐标与外在视觉坐标之间的注意力依赖切换。外部视觉坐标至少可以满足特定任务要求的目标导向的双手运动。对由双边手部运动控制的综合视觉对象的关注与偏爱外部视觉坐标以同步双边运动方向的偏好相关（实验2）。因此，在双手运动过程中观察到内在肌肉坐标与外在视觉坐标之间的注意力依赖切换。外部视觉坐标至少可以满足特定任务要求的目标导向的双手运动。对由双边手部运动控制的综合视觉对象的关注与偏爱外部视觉坐标以同步双边运动方向的偏好相关（实验2）。因此，在双手运动过程中观察到内在肌肉坐标与外在视觉坐标之间的注意力依赖切换。外部视觉坐标至少可以满足特定任务要求的目标导向的双手运动。