Wheaton Lewis A, Shibasaki Hiroshi, Hallett Mark
Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, MD 20892-1428 Maryland, USA.
Clin Neurophysiol. 2005 May;116(5):1201-12. doi: 10.1016/j.clinph.2005.01.001.
We sought to determine the cortical physiology underlying praxis movements in normal subjects using electroencephalography (EEG).
Eight normal subjects were instructed to perform six types of self-paced tool-use pantomime and communicative gesture movements with the right hand. We recorded 64-channel EEG using a linked ear reference and electromyogram (EMG) from right thumb and forearm flexors.
Data revealed early slow wave components of the movement-related cortical potential (MRCP) beginning over the left parietal area about 3s before movement onset, similarly for both movement types. At movement onset, maximal amplitude was present over central and bilateral sensorimotor areas. Event-related desynchronization (ERD) in the beta band was seen over the left parietal and sensorimotor cortices during preparation, later spreading to the homologous area of the right hemisphere. Alpha ERD was mainly in the left sensorimotor cortex about 1.5s before movement onset. Beta ERD in mesial frontal areas was greater during preparation for tool use compared to communicative gesture movements. Mesial frontal beta event-related synchronization (ERS) developed more rapidly after communicative gestures than tool-use.
The dynamics of parietal and frontal activities indicates the timing of these areas in the production of praxis. The posterior parietal cortex contributes to the early slow wave negativity of the MRCP.
Planning self-paced praxis movements begins as early as 3s before movement in the left parietal area and subsequently engages frontal cortical regions.
我们试图利用脑电图（EEG）确定正常受试者中运用动作的皮质生理学机制。
八名正常受试者被要求用右手进行六种类型的自定节奏工具使用哑剧和交流手势动作。我们使用双耳链接参考记录64通道脑电图，并记录右手拇指和前臂屈肌的肌电图（EMG）。
数据显示，与动作相关的皮质电位（MRCP）的早期慢波成分在动作开始前约3秒从左顶叶区域开始出现，两种动作类型情况相似。在动作开始时，中央和双侧感觉运动区域出现最大振幅。在准备过程中，左侧顶叶和感觉运动皮质出现β频段的事件相关去同步化（ERD），随后扩散到右半球的同源区域。α波ERD主要出现在动作开始前约1.5秒的左侧感觉运动皮质。与交流手势动作相比，在准备工具使用过程中，内侧额叶区域的β波ERD更大。交流手势后内侧额叶β波事件相关同步化（ERS）比工具使用发展得更快。
顶叶和额叶活动的动态变化表明这些区域在运用动作产生过程中的时间安排。顶叶后皮质对MRCP的早期慢波负相有贡献。
自定节奏运用动作的计划早在动作开始前3秒就在左侧顶叶区域开始，随后涉及额叶皮质区域。
