Movement related beta band cortical oscillations, including beta rebound after execution and/or suppression of movement, have drawn attention in upper extremity motor control literature. However, fewer studies focused on beta band oscillations during postural control in upright stance. In this preliminary study, we examined beta rebound and other components of electroencephalogram (EEG) activity during perturbed upright stance to investigate supraspinal contributions to postural stabilization. Particularly, we aimed to clarify the timing and duration of beta rebound within a non-sustained, but long-lasting postural recovery process that occurs more slowly compared to upper extremities. To this end, EEG signals were acquired from nine healthy young adults in response to a brief support-surface perturbation, together with the center of pressure, the center of mass and electromyogram (EMG) activities of ankle muscles. Event-related potentials (ERPs) and event-related spectral perturbations were computed from EEG data using the perturbation-onset as a triggering event. After short-latency (< 0.3 s) ERPs, our results showed a decrease in high-beta band oscillations (event-related desynchronization), which was followed by a significant increase (event-related synchronization) in the same band, as well as a decrease in theta band oscillations. Unlike during upper extremity motor tasks, the beta rebound in this case was initiated before the postural recovery was completed, and sustained for as long as three seconds with small EMG responses for the first half period, followed by no excessive EMG activities for the second half period. We speculate that those novel characteristics of beta rebound might be caused by slow postural dynamics along a stable manifold of the unstable saddle-type upright equilibrium of the postural control system without active feedback control, but with active monitoring of the postural state, in the framework of the intermittent control.

中文翻译：

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直立站立期间支撑表面扰动的脑电图活动的长期事件相关β同步：一项将间歇性姿势控制中的β反弹和主动监测相关联的初步研究


运动相关的β带皮质振荡，包括执行和/或抑制运动后的β反弹，已引起上肢运动控制文献的关注。然而，很少有研究关注直立姿势控制期间的β带振荡。在这项初步研究中，我们检查了直立姿势受到干扰时的 β 回弹和脑电图 (EEG) 活动的其他组成部分，以研究脊柱上对姿势稳定的贡献。特别是，我们的目的是澄清在非持续但持久的姿势恢复过程中β反弹的时间和持续时间，该过程与上肢相比发生得更慢。为此，我们从九名健康的年轻人身上获取了对短暂支撑面扰动的脑电图信号，以及压力中心、质心和踝关节肌肉的肌电图 (EMG) 活动。使用扰动发生作为触发事件，根据脑电图数据计算事件相关电位（ERP）和事件相关频谱扰动。在短延迟 (< 0.3 s) ERP 后，我们的结果显示高 beta 带振荡（与事件相关的去同步）减少，随后同一带中的高 beta 带振荡（与事件相关的同步）显着增加θ 带振荡的减少。与上肢运动任务不同，本例中的β反弹是在姿势恢复完成之前开始的，并持续长达三秒，前半段肌电图反应较小，随后后半段没有过度的肌电图活动时期。 我们推测，β 反弹的这些新特征可能是由沿着姿势控制系统的不稳定鞍型直立平衡的稳定流形的缓慢姿势动力学引起的，没有主动反馈控制，但在框架中主动监测姿势状态。的间歇控制。