Schnitzler A, Salenius S, Salmelin R, Jousmäki V, Hari R
Low Temperature Laboratory, Helsinki University of Technology, Helsinki, FIN-02015 HUT, Finland.
Neuroimage. 1997 Oct;6(3):201-8. doi: 10.1006/nimg.1997.0286.
Functional brain imaging studies have indicated that several cortical and subcortical areas active during actual motor performance are also active during imagination or mental rehearsal of movements. Recent evidence shows that the primary motor cortex may also be involved in motor imagery. Using whole-scalp magnetoencephalography, we monitored spontaneous and evoked activity of the somatomotor cortex after right median nerve stimuli in seven healthy right-handed subjects while they kinesthetically imagined or actually executed continuous finger movements. Manipulatory finger movements abolished the poststimulus 20-Hz activity of the motor cortex and markedly affected the somatosensory evoked response. Imagination of manipulatory finger movements attenuated the 20-Hz activity by 27% with respect to the rest level but had no effect on the somatosensory response. Slight constant stretching of the fingers suppressed the 20-Hz activity less than motor imagery. The smallest possible, kinesthetically just perceivable finger movements resulted in slightly stronger attenuation of 20-Hz activity than motor imagery did. The effects were observed in both hemispheres but predominantly contralateral to the performing hand. The attempt to execute manipulatory finger movements under experimentally induced ischemia causing paralysis of the hand also strongly suppressed 20-Hz activity but did not affect the somatosensory evoked response. The results indicate that the primary motor cortex is involved in motor imagery. Both imaginative and executive motor tasks appear to utilize the cortical circuitry generating the somatomotor 20-Hz signal.
功能性脑成像研究表明，在实际运动表现过程中活跃的几个皮层和皮层下区域，在运动想象或心理演练时也会活跃。最近的证据表明，初级运动皮层也可能参与运动想象。我们使用全头皮脑磁图，在7名健康的右利手受试者右正中神经刺激后，监测他们在进行动觉想象或实际执行连续手指运动时躯体运动皮层的自发和诱发活动。手指操作运动消除了运动皮层刺激后的20赫兹活动，并显著影响体感诱发电位。操作手指运动的想象使20赫兹活动相对于静息水平衰减了27%，但对体感反应没有影响。手指的轻微持续伸展对20赫兹活动的抑制作用小于运动想象。最小的、动觉上刚刚可感知的手指运动导致20赫兹活动的衰减略强于运动想象。在两个半球均观察到了这些效应，但主要在与执行手对侧的半球。在实验性诱导的手部缺血性麻痹情况下尝试执行手指操作运动也强烈抑制了20赫兹活动，但不影响体感诱发电位。结果表明初级运动皮层参与运动想象。想象性和执行性运动任务似乎都利用了产生躯体运动20赫兹信号的皮层回路。
