Visuomotor Transformation for the Lead Leg Affects Trail Leg Trajectories During Visually Guided Crossing Over a Virtual Obstacle in Humans
Visuomotor Transformation for the Lead Leg Affects Trail Leg Trajectories During Visually Guided Crossing Over a Virtual Obstacle in Humans
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DOI：
10.3389/fnins.2020.00357
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发表时间：
2020-04-23
影响因子：
4.3
通讯作者：
Kouzaki, Motoki
中科院分区：
文献类型：
--
作者：
Hagio, Shota;Kouzaki, Motoki
当在房间或室外走动时，我们经常需要协商外部的物理物体，例如走上楼梯或跨过障碍物。在以往关于障碍物回避的研究中，人类的前导和尾部腿被认为是基于关于障碍属性的视觉输入而被独立控制的。然而，这一观点还不够充分，因为由于跨过物理障碍的实验任务中的技术限制，前腿中的视觉运动转换对后腿的影响还没有完全阐明。在这项研究中，我们使用一项视觉引导的穿越虚拟障碍的任务，研究了前腿的视觉运动转换如何影响后腿的运动轨迹。先建立跨越物理障碍的试验，然后进行视觉引导任务，在这些任务中，与受试者的前肢和尾肢脚趾位置相对应的光标显示在头戴式显示设备上。受试者被指示操纵光标，以便他们准确地越过虚拟障碍。在试验过程中，在一次或两次连续试验中，相对于实际的脚趾移动，光标仅在领先腿中的垂直位移减少。这种视觉运动扰动不仅导致前肢脚趾位置的高度升高，而且还导致尾肢脚趾轨迹的高度升高，然后在冲刷试验中脚趾高度恢复到基线，这表明前腿避障的视觉运动转换影响了尾腿轨迹。综上所述，用于前腿和尾腿跨越障碍运动的肢体特定运动记忆的神经资源可以基于关于障碍属性的视觉输入来共享。
When walking around a room or outside, we often need to negotiate external physical objects, such as walking up stairs or stepping over an obstacle. In previous studies on obstacle avoidance, lead and trail legs in humans have been considered to be controlled independently on the basis of visual input regarding obstacle properties. However, this perspective has not been sufficient because the influence of visuomotor transformation in the lead leg on the trail leg has not been fully elucidated due to technical limitations in the experimental tasks of stepping over physical obstacles. In this study, we investigated how visuomotor transformation in the lead leg affected movement trajectories in the trail leg using a visually guided task of crossing over a virtual obstacle. Trials for stepping over a physical obstacle were established followed by visually guided tasks in which cursors corresponding to the subject's lead and trail limb toe positions were displayed on a head-mounted display apparatus. Subjects were instructed to manipulate the cursors so that they precisely crossover a virtual obstacle. In the middle of the trials, the vertical displacement of the cursor only in the lead leg was reduced relative to the actual toe movement during one or two consecutive trials. This visuomotor perturbation resulted in higher elevation not only in the lead limb toe position but also in the trail limb toe trajectories, and then the toe heights returned to the baseline in washout trials, indicating that the visuomotor transformation for obstacle avoidance in the lead leg affects the trail leg trajectory. Taken together, neural resources of limb-specific motor memories for obstacle crossing movements in the lead and trail legs can be shared based on visual input regarding obstacle properties.