Institut des Sciences Cognitives Marc Jeannerod, CNRS UMR 5229, Bron, France; Université Claude Bernard Lyon 1, Université de Lyon, France; Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London (UCL), London, WC1N 3BG, UK; Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, University College London (UCL), London, WC1N 3BG, UK.
Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, University College London (UCL), London, WC1N 3BG, UK; Department of Neurology, University of California San Francisco, San Francisco, CA, USA.
Neuroimage. 2021 Nov 15;242:118479. doi: 10.1016/j.neuroimage.2021.118479. Epub 2021 Aug 15.
Motor cortical activity in the beta frequency range is one of the strongest and most studied movement-related neural signals. At the single trial level, beta band activity is often characterized by transient, high amplitude, bursting events rather than slowly modulating oscillations. The timing of these bursting events is tightly linked to behavior, suggesting a more dynamic functional role for beta activity than previously believed. However, the neural mechanisms underlying beta bursts in sensorimotor circuits are poorly understood. To address this, we here leverage and extend recent developments in high precision MEG for temporally resolved laminar analysis of burst activity, combined with a neocortical circuit model that simulates the biophysical generators of the electrical currents which drive beta bursts. This approach pinpoints the generation of beta bursts in human motor cortex to distinct excitatory synaptic inputs to deep and superficial cortical layers, which drive current flow in opposite directions. These laminar dynamics of beta bursts in motor cortex align with prior invasive animal recordings within the somatosensory cortex, and suggest a conserved mechanism for somatosensory and motor cortical beta bursts. More generally, we demonstrate the ability for uncovering the laminar dynamics of event-related neural signals in human non-invasive recordings. This provides important constraints to theories about the functional role of burst activity for movement control in health and disease, and crucial links between macro-scale phenomena measured in humans and micro-circuit activity recorded from animal models.
运动皮层在β频带范围内的活动是与运动相关的最强和研究最多的神经信号之一。在单次试验水平上，β频带活动通常表现为短暂、高振幅、爆发事件，而不是缓慢调制的振荡。这些爆发事件的时间与行为紧密相关，表明β活动在功能上比以前认为的更具动态性。然而，感觉运动回路中β爆发的神经机制还知之甚少。为了解决这个问题，我们在这里利用并扩展了高精度 MEG 在时间上分辨的层分析爆发活动的最新进展，结合模拟驱动β爆发的电流的生物物理发生器的新皮质电路模型。这种方法将β爆发的产生定位到深和浅皮质层的不同兴奋性突触输入，这些输入驱动电流的流向相反。运动皮层中β爆发的这些层动态与体感皮层内先前的侵入性动物记录一致，并表明体感和运动皮层β爆发具有保守的机制。更一般地说，我们证明了在人类非侵入性记录中揭示与事件相关的神经信号的层动态的能力。这为有关爆发活动在健康和疾病中的运动控制的功能作用的理论提供了重要的限制，并为在人类中测量的宏观现象与从动物模型记录的微电路活动之间提供了关键联系。
