Romero D H, Lacourse M G, Lawrence K E, Schandler S, Cohen M J
Behavioral Medicine Laboratory, Veteran's Affairs Healthcare System, Long Beach, CA, USA.
Behav Brain Res. 2000 Dec 20;117(1-2):83-96. doi: 10.1016/s0166-4328(00)00297-7.
Neuroimaging and electrophysiological studies have shown that executed action and motor imagery activate common neuronal substrates, leading to the hypothesis that movement preparation and motor imagery are functionally equivalent processes. This study further tested the functional equivalence hypothesis by determining whether electrocortical patterns associated with variations in motor control parameters are similar during imagined and executed actions. Event-related potentials (ERPs) were recorded from the supplementary motor/premotor area (SMA/PMA; FCz site) and primary motor area (M1; C3, C4 sites) during an executed and an imagined, cued, discrete isometric contraction task while target force (TF; low, moderate) and rate of force development (RFD; slow, rapid) were varied. For M1, the correlation of ERPs between moderate- and low force-executions was near zero and N2 amplitude was greater for moderate than low force executions, indicating that M1 activity is related to TF. Rapid executions were greater in amplitude and longer in latency than slow executions and the ERPs for rapid- and slow-executions were negatively correlated, indicating that M1 activity is also related to RFD. There were no differences in N2 amplitude and a zero correlation between execution and imagined actions of similar TF and RFD, indicating that neither TF or RFD are represented in M1 activity during imagery. For SMA/PMA, there was a moderate correlation between moderate- and low force-executions and larger N2 amplitude for moderate- than for low force-executions, indicating that TF may be related to SMA/PMA electrocortical activity. ERP patterns were uncorrelated between rapid- and slow-execution at FCz, but N2 amplitude was the same, making it unclear whether the RFD parameter is represented in FCz activity. The correlational and N2 amplitude analyses demonstrate that patterns of electrocortical activity at SMA/PMA are nearly isomorphic during executed and imagined actions as TF and RFD are varied. These results provide evidence that patterns of electrocortical activity associated with variations in the parameters of executed action are similar during motor imagery at SMA/PMA but not at M1.
神经影像学和电生理学研究表明，执行动作和运动想象会激活共同的神经元基质，从而得出运动准备和运动想象在功能上是等效过程的假设。本研究通过确定在想象动作和执行动作期间，与运动控制参数变化相关的皮层电活动模式是否相似，进一步检验了功能等效假设。在执行和想象的、有提示的、离散的等长收缩任务中，当目标力（TF；低、中）和力发展速率（RFD；慢、快）变化时，从辅助运动区/运动前区（SMA/PMA；FCz部位）和初级运动区（M1；C3、C4部位）记录事件相关电位（ERP）。对于M1，中等力和低力执行之间的ERP相关性接近零，中等力执行的N2波幅大于低力执行，表明M1活动与TF相关。快速执行的波幅大于慢速执行，潜伏期更长，快速和慢速执行的ERP呈负相关，表明M1活动也与RFD相关。在相似的TF和RFD的执行动作和想象动作之间，N2波幅没有差异且相关性为零，表明在想象过程中，M1活动中既不代表TF也不代表RFD。对于SMA/PMA，中等力和低力执行之间存在中等相关性，中等力执行的N2波幅大于低力执行，表明TF可能与SMA/PMA皮层电活动相关。在FCz部位，快速和慢速执行之间的ERP模式不相关，但N2波幅相同，则不清楚RFD参数是否在FCz活动中体现。相关性和N2波幅分析表明，随着TF和RFD的变化，在执行和想象动作期间，SMA/PMA的皮层电活动模式几乎是同构的。这些结果提供了证据，表明与执行动作参数变化相关的皮层电活动模式在SMA/PMA的运动想象过程中相似，但在M1中并非如此。
