Radboud Universitary Medical centre for Medical Neuroscience, Department of Rehabilitation, Reinier Postlaan 4, 6525 GC Nijmegen, The Netherlands.
Donders Institute for Brain cognition and behavior, Department of synchronisation in neural systems Kappitelweg 29,6525 EN Nijmegen, The Netherlands.
Cereb Cortex. 2023 Mar 21;33(7):3454-3466. doi: 10.1093/cercor/bhac283.
Stepping is a common strategy to recover postural stability and maintain upright balance. Postural perturbations have been linked to neuroelectrical markers such as the N1 potential and theta frequency dynamics. Here, we investigated the role of cortical midfrontal theta dynamics of balance monitoring, driven by balance perturbations at different initial standing postures. We recorded electroencephalography, electromyography, and motion tracking of human participants while they stood on a platform that delivered a range of forward and backward whole-body balance perturbations. The participants' postural threat was manipulated prior to the balance perturbation by instructing them to lean forward or backward while keeping their feet-in-place in response to the perturbation. We hypothesized that midfrontal theta dynamics index the engagement of a behavioral monitoring system and, therefore, that perturbation-induced theta power would be modulated by the initial leaning posture and perturbation intensity. Targeted spatial filtering in combination with mixed-effects modeling confirmed our hypothesis and revealed distinct modulations of theta power according to postural threat. Our results provide novel evidence that midfrontal theta dynamics subserve action monitoring of human postural balance. Understanding of cortical mechanisms of balance control is crucial for studying balance impairments related to aging and neurological conditions (e.g. stroke).
迈步是一种常见的恢复姿势稳定性和维持直立平衡的策略。姿势扰动与神经电标记物有关，如 N1 电位和θ频动态。在这里，我们研究了由不同初始站立姿势的平衡扰动驱动的平衡监测中皮质额中θ动态的作用。我们记录了人类参与者的脑电图、肌电图和运动跟踪，同时他们站在一个平台上，该平台提供了一系列向前和向后的全身平衡扰动。在平衡扰动之前，通过指示参与者在响应扰动时前倾或后倾，同时保持脚在原地，来操纵参与者的姿势威胁。我们假设额中θ动态指数了行为监测系统的参与，因此，扰动诱导的θ功率将受到初始倾斜姿势和扰动强度的调制。靶向空间滤波与混合效应模型相结合，证实了我们的假设，并根据姿势威胁揭示了θ功率的明显调制。我们的结果提供了新的证据，表明额中θ动态有助于人类姿势平衡的动作监测。对平衡控制的皮质机制的理解对于研究与衰老和神经状况（如中风）相关的平衡障碍至关重要。
