Foulger Liam H, Kuo Calvin, Chua Romeo, Blouin Jean-Sébastien
School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.
School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada.
Sci Rep. 2025 May 28;15(1):18670. doi: 10.1038/s41598-025-99878-w.
The unstable nature of our bipedal posture requires continuous feedback to maintain internal estimates of self-motion and generate appropriate balance-correcting responses. This feedback control process involves the integration of multisensory information, including vestibular cues of head motion. Minimizing head motion variability may optimize the information transmitted by vestibular signals that are important for balance control and consequently drive vestibular contributions to locomotion which decrease as we move faster. In this study, participants walked outdoors at 40% to 140% of their preferred step cadence while we characterized head kinematic variability and vestibular-evoked balance responses to electrical vestibular stimulation, a common method to generate virtual signals of head movement. Head kinematic variability was lowest near participants' preferred step cadences (90-126 steps/min) and gait speeds (1.1-1.7 m/s) while vestibular-evoked responses decreased exponentially as step cadence and gait speed increased. Hence, the minima of head kinematic variability were close to preferred step cadences, near previously established minima for the metabolic cost of locomotion. The relationship between head kinematic variability and vestibular-evoked balance responses, however, was inconsistent across all step cadences, suggesting that head kinematic variability did not drive vestibular-evoked balance response magnitude. The observed reduction in the variability of head motion signals at the preferred locomotor cadence/speed may serve to improve our self-motion estimates and reduce information processing requirements to ensure effective navigation, thereby potentially contributing to the well-established minimum in metabolic cost near preferred cadence.
我们两足姿势的不稳定特性需要持续的反馈，以维持对自身运动的内部估计，并产生适当的平衡校正反应。这种反馈控制过程涉及多感官信息的整合，包括头部运动的前庭线索。尽量减少头部运动的变异性，可能会优化前庭信号传输的信息，这些信息对平衡控制很重要，从而驱动前庭对运动的贡献，而这种贡献会随着我们移动速度的加快而减少。在这项研究中，参与者在户外以其偏好步频的40%至140%行走，同时我们描绘了头部运动学变异性以及对电前庭刺激的前庭诱发平衡反应，电前庭刺激是一种产生头部运动虚拟信号的常用方法。头部运动学变异性在参与者的偏好步频（90 - 126步/分钟）和步态速度（1.1 - 1.7米/秒）附近最低，而前庭诱发反应随着步频和步态速度的增加呈指数下降。因此，头部运动学变异性的最小值接近偏好步频，接近先前确定的运动代谢成本最小值。然而，在所有步频中，头部运动学变异性与前庭诱发平衡反应之间的关系并不一致，这表明头部运动学变异性并未驱动前庭诱发平衡反应的大小。在偏好的运动步频/速度下观察到的头部运动信号变异性降低，可能有助于改善我们对自身运动的估计，并减少信息处理需求以确保有效导航，从而可能导致在偏好步频附近代谢成本的既定最小值。
