Visual control of trunk translation and orientation during locomotion
Visual control of trunk translation and orientation during locomotion
复制标题
DOI：
10.1007/s00221-014-3885-1
复制
发表时间：
2014-06-01
影响因子：
2
通讯作者：
Jeka, J.
中科院分区：
文献类型：
--
作者：
Anson, E.;Agada, P.;Jeka, J.
先前的研究表明，响应视觉输入，对前后（AP）和内侧-外侧（ML）方向的步态特征进行不同的控制。对 ML 视觉刺激的反应更大，表明视觉在稳定 ML 方向的步态方面发挥着更大的作用。在这里，我们研究了运动过程中躯干的反应，以确定是否观察到类似的方向依赖性。我们假设躯干的平移会表现出类似的机器学习对视觉的依赖，但躯干的角度偏差会在所有方向上表现出等效的响应。受试者以 5 公里/小时的速度在跑步机上站立或行走，同时观察白色三角形的虚拟墙，这些三角形根据宽带输入刺激向 AP 或 ML 方向移动。视觉场景运动和躯干运动学之间的频率响应函数表明，与站立相比，步行时所有频率的躯干平移增益都更大。躯干定向反应与站立在非常低的频率下没有什么不同；然而，在高频率下，行走期间躯干定向增益要高得多。所有躯干运动对机器学习视觉场景运动的响应都有更大的增益。行走时 ML 方向的增益较高表明视觉反馈可能对 ML 方向躯干运动的稳定性有更大贡献。视觉在慢（平移）和快（方向）时间尺度上改变了躯干运动行为，这表明优先考虑尽量减少躯干的角度偏差。总体而言，躯干对视觉输入的反应与运动控制需要更高级别的感官输入以保持机器学习方向的稳定性的主题一致。
Previous studies have suggested distinct control of gait characteristics in the anterior-posterior (AP) and medial-lateral (ML) directions in response to visual input. Responses were larger to a ML visual stimulus, suggesting that vision plays a larger role in stabilizing gait in the ML direction. Here, we investigated responses of the trunk during locomotion to determine whether a similar direction dependence is observed. We hypothesized that translation of the trunk would show a similar ML dependence on vision, but that angular deviations of the trunk would show equivalent responses in all directions. Subjects stood or walked on a treadmill at 5 km/h while viewing a virtual wall of white triangles that moved in either the AP or ML direction according to a broadband input stimulus. Frequency response functions between the visual scene motion and trunk kinematics revealed that trunk translation gain was larger across all frequencies during walking compared with standing. Trunk orientation responses were not different from standing at very low frequencies; however, at high frequencies, trunk orientation gain was much higher during walking. Larger gains in response to ML visual scene motion were found for all trunk movements. Higher gains in the ML direction while walking suggest that visual feedback may contribute more to the stability of trunk movements in the ML direction. Vision modified trunk movement behavior on both a slow (translation) and fast (orientation) time scale suggesting a priority for minimizing angular deviations of the trunk. Overall, trunk responses to visual input were consistent with the theme that control of locomotion requires higher-level sensory input to maintain stability in the ML direction.