Department of Nutrition, Exercise and Sports, University of Copenhagen, Nørre Allé 51, 2200 Copenhagen N, Denmark.
Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, London WC1N 3AR, United Kingdom.
Cereb Cortex. 2022 Dec 20;33(2):258-277. doi: 10.1093/cercor/bhac066.
The cortical mechanisms underlying the act of taking a step-including planning, execution, and modification-are not well understood. We hypothesized that oscillatory communication in a parieto-frontal and corticomuscular network is involved in the neural control of visually guided steps. We addressed this hypothesis using source reconstruction and lagged coherence analysis of electroencephalographic and electromyographic recordings during visually guided stepping and 2 control tasks that aimed to investigate processes involved in (i) preparing and taking a step and (ii) adjusting a step based on visual information. Steps were divided into planning, initiation, and execution phases. Taking a step was characterized by an upregulation of beta/gamma coherence within the parieto-frontal network during planning followed by a downregulation of alpha and beta/gamma coherence during initiation and execution. Step modification was characterized by bidirectional modulations of alpha and beta/gamma coherence in the parieto-frontal network during the phases leading up to step execution. Corticomuscular coherence did not exhibit task-related effects. We suggest that these task-related modulations indicate that the brain makes use of communication through coherence in the context of large-scale, whole-body movements, reflecting a process of flexibly fine-tuning inter-regional communication to achieve precision control during human stepping.
目前对于迈步这一行为背后的皮质机制（包括计划、执行和修正）还没有清晰的认识。我们假设在顶-额皮质网络和皮质肌肉网络中的振荡性通信参与了视觉引导下迈步的神经控制。我们通过在视觉引导下迈步以及两个控制任务中对脑电和肌电记录进行源重建和滞后相干性分析来验证这个假说，这两个控制任务旨在分别研究以下过程：（i）准备和迈步，（ii）基于视觉信息来调整迈步。我们将迈步分为计划、启动和执行三个阶段。在计划阶段，顶-额皮质网络中的β/γ相干性增强，在启动和执行阶段则减弱。在执行阶段前的阶段中，顶-额皮质网络中的α和β/γ相干性出现双向调制，表明对迈步进行了修正。皮质肌肉相干性并未表现出与任务相关的影响。我们认为，这些与任务相关的调制表明，在涉及大型全身运动的情况下，大脑利用相干性进行通信，反映了一个灵活微调区域间通信的过程，从而实现人类迈步时的精确控制。
