Heinrichs-Graham Elizabeth, Wilson Tony W
Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center (UNMC), Omaha, Nebraska.
Center for Magnetoencephalography, UNMC, Omaha, Nebraska.
Hum Brain Mapp. 2015 Dec;36(12):5155-67. doi: 10.1002/hbm.23000. Epub 2015 Sep 25.
Cortical oscillatory dynamics are known to be critical for human movement, although their functional significance remains unclear. In particular, there is a strong beta (15-30 Hz) desynchronization that begins before movement onset and continues during movement, before rebounding after movement termination. Several studies have connected this response to motor planning and/or movement selection operations, but to date such studies have examined only the early aspects of the response (i.e., before movement) and a limited number of parameters. In this study, we used magnetoencephalography (MEG) and a novel motor sequence paradigm to probe how motor plan complexity modulates peri-movement beta oscillations, and connectivity within activated circuits. We also examined the dynamics by imaging beta activity before and during movement execution and extracting virtual sensors from key regions. We found stronger beta desynchronization during complex relative to simple sequences in the right parietal and left dorsolateral prefrontal cortex (DLPFC) during movement execution. There was also an increase in functional connectivity between the left DLPFC and right parietal shortly after movement onset during complex but not simple sequences, which produced a significant conditional effect (i.e., complex > simple) that was not attributable to differences in response amplitude. This study is the first to demonstrate that complexity modulates the dynamics of the peri-movement beta ERD, which provides crucial new data on the functional role of this well-known oscillatory motor response. These data further suggest that execution of complex motor behavior may recruit key regions of the fronto-parietal network, in addition to traditional sensorimotor regions.
已知皮质振荡动力学对人类运动至关重要，尽管其功能意义仍不明确。特别是，在运动开始前会出现强烈的β波（15 - 30赫兹）去同步化，并在运动过程中持续，在运动终止后反弹。多项研究将这种反应与运动计划和/或运动选择操作联系起来，但迄今为止，此类研究仅考察了反应的早期阶段（即运动前）以及有限数量的参数。在本研究中，我们使用脑磁图（MEG）和一种新颖的运动序列范式来探究运动计划复杂性如何调节运动周围的β振荡以及激活回路内的连接性。我们还通过在运动执行前和执行过程中对β活动进行成像，并从关键区域提取虚拟传感器来研究其动态变化。我们发现，在运动执行过程中，相对于简单序列，复杂序列在右侧顶叶和左侧背外侧前额叶皮质（DLPFC）中会出现更强的β去同步化。在复杂序列而非简单序列中，运动开始后不久，左侧DLPFC与右侧顶叶之间的功能连接也有所增加，这产生了显著的条件效应（即复杂 > 简单），且该效应并非由反应幅度的差异所致。本研究首次证明复杂性可调节运动周围β事件相关去同步化（ERD）的动态变化，这为这种著名的振荡运动反应的功能作用提供了关键的新数据。这些数据进一步表明，除了传统的感觉运动区域外，复杂运动行为的执行可能会招募额顶网络的关键区域。
