Gray Julia, Roth Adam, Reimann Hendrik, Buggeln John, Cashaback Joshua G A, Jeka John
Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States; Biomechanics and Movements Science Program, University of Delaware, Newark, DE, United States.
Department of Mechanical Engineering, University of Delaware, Newark, DE, United States.
Gait Posture. 2025 Sep;121:377-383. doi: 10.1016/j.gaitpost.2025.06.015. Epub 2025 Jun 21.
Reinforcement and error feedback are known to encourage motor exploration and learning. Studies of the upper limb have shown that reaches that are not rewarded lead to greater exploration, because the nervous system utilizes knowledge of movement variability to update aim towards a successful "reinforced" action. The current study investigated how reinforcement and error feedback influences motor exploration while walking and its impact on upright balance control.
Twenty-four healthy young subjects walked on an instrumented treadmill with a 180° virtual reality screen presenting feedback on their step length or step width. Subjects were instructed to match a target step length or width. Visual error feedback displayed their left foot step length or width as a black line within a target area. Reinforcement feedback displayed a gray target box that would turn blue when their left foot stepped within the box. We calculated lag-1 autocorrelations to assess exploratory behavior. Linear models of ankle roll and step placement were applied to assess whether the recruitment of balance mechanisms differed across feedback conditions.
Both baseline walking and reinforcement feedback conditions led to greater motor exploration than error feedback for step length, but not for step width. Error feedback yielded corrective behavior, narrowing in on the target center regardless of target direction. Lag-1 values during reinforcement feedback were similar to baseline walking for both target directions. Analysis of the balance mechanisms showed that step width feedback changed balance strategy use. Center of mass was less predictive of ankle roll for the step width target conditions than at baseline.
The regulation of step length follows similar trends to the regulation of upper body reaching behaviour under both error and reinforcement feedback. However, maintaining balance leads to reduced exploration for step width targets, and altered balance mechanism use in response to feedback.
已知强化和错误反馈可促进运动探索和学习。上肢研究表明，未得到奖励的伸手动作会导致更多探索，因为神经系统利用运动变异性知识来更新目标，以实现成功的“强化”动作。本研究调查了强化和错误反馈如何影响行走时的运动探索及其对直立平衡控制的影响。
24名健康年轻受试者在装有仪器的跑步机上行走，跑步机带有一个180°虚拟现实屏幕，可呈现有关他们步长或步宽的反馈。受试者被要求匹配目标步长或步宽。视觉错误反馈在目标区域内将他们左脚的步长或步宽显示为一条黑线。强化反馈显示一个灰色目标框，当他们左脚踏入框内时，该框会变为蓝色。我们计算滞后1自相关以评估探索行为。应用踝关节滚动和步幅放置的线性模型来评估平衡机制的募集在不同反馈条件下是否存在差异。
对于步长而言，基线行走和强化反馈条件均比错误反馈导致更大的运动探索，但步宽方面并非如此。错误反馈产生纠正行为，无论目标方向如何，都向目标中心靠拢。在两种目标方向的强化反馈期间，滞后1值与基线行走相似。对平衡机制的分析表明，步宽反馈改变了平衡策略的使用。与基线相比，在步宽目标条件下，质心对踝关节滚动的预测性较低。
在错误和强化反馈下，步长的调节遵循与上身伸手行为调节相似的趋势。然而，保持平衡会导致对步宽目标的探索减少，并根据反馈改变平衡机制的使用。
