Yi Weibo, Qiu Shuang, Wang Kun, Qi Hongzhi, Zhang Lixin, Zhou Peng, He Feng, Ming Dong
Department of Biomedical Engineering, Tianjin University, Tianjin, China; Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin, China.
PLoS One. 2014 Dec 9;9(12):e114853. doi: 10.1371/journal.pone.0114853. eCollection 2014.
Motor imagery (MI), sharing similar neural representations to motor execution, is regarded as a window to investigate the cognitive motor processes. However, in comparison to simple limb motor imagery, significantly less work has been reported on brain oscillatory patterns induced by compound limb motor imagery which involves several parts of limbs. This study aims to investigate differences of the electroencephalogram (EEG) patterns as well as cognitive process between simple limb motor imagery and compound limb motor imagery. Ten subjects participated in the experiment involving three tasks of simple limb motor imagery (left hand, right hand, feet) and three tasks of compound limb motor imagery (both hands, left hand combined with right foot, right hand combined with left foot). Simultaneous imagination of different limbs contributes to the activation of larger cortical areas as well as two estimated sources located at corresponding motor areas within beta rhythm. Compared with simple limb motor imagery, compound limb motor imagery presents a network with more effective interactions overlying larger brain regions, additionally shows significantly larger causal flow over sensorimotor areas and larger causal density over both sensorimotor areas and neighboring regions. On the other hand, compound limb motor imagery also shows significantly larger 10-11 Hz alpha desynchronization at occipital areas and central theta synchronization. Furthermore, the phase-locking value (PLV) between central and occipital areas of left/right hand combined with contralateral foot imagery is significantly larger than that of simple limb motor imagery. All these findings imply that there exist apparent intrinsic distinctions of neural mechanism between simple and compound limb motor imagery, which presents a more complex effective connectivity network and may involve a more complex cognitive process during information processing.
运动想象（MI）与运动执行共享相似的神经表征，被视为研究认知运动过程的一扇窗口。然而，与简单肢体运动想象相比，关于涉及多个肢体部位的复合肢体运动想象所诱发的脑振荡模式的研究报道要少得多。本研究旨在探究简单肢体运动想象和复合肢体运动想象之间脑电图（EEG）模式以及认知过程的差异。10名受试者参与了该实验，实验包含简单肢体运动想象的三项任务（左手、右手、双脚）和复合肢体运动想象的三项任务（双手、左手与右脚组合、右手与左脚组合）。同时想象不同肢体有助于激活更大的皮质区域以及位于β节律内相应运动区域的两个估计源。与简单肢体运动想象相比，复合肢体运动想象呈现出一个在更大脑区上具有更有效交互作用的网络，此外在感觉运动区域显示出显著更大的因果流，在感觉运动区域和相邻区域显示出更大的因果密度。另一方面，复合肢体运动想象在枕叶区域也显示出显著更大的10 - 11Hzα去同步化和中央θ同步化。此外，左手/右手与对侧脚想象的中央和枕叶区域之间的锁相值（PLV）显著大于简单肢体运动想象。所有这些发现表明，简单和复合肢体运动想象之间存在明显的神经机制内在差异，复合肢体运动想象呈现出更复杂的有效连接网络，并且在信息处理过程中可能涉及更复杂的认知过程。
