ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, Australia.
Neuroimage. 2013 May 1;71:50-8. doi: 10.1016/j.neuroimage.2013.01.001. Epub 2013 Jan 12.
Neuroimaging studies have shown that the neural mechanisms of motor imagery (MI) overlap substantially with the mechanisms of motor execution (ME). Surprisingly, however, the role of several regions of the motor circuitry in MI remains controversial, a variability that may be due to differences in neuroimaging techniques, MI training, instruction types, or tasks used to evoke MI. The objectives of this study were twofold: (i) to design a novel task that reliably invokes MI, provides a reliable behavioral measure of MI performance, and is transferable across imaging modalities; and (ii) to measure the common and differential activations for MI and ME with functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG). We present a task in which it is difficult to give accurate responses without the use of either motor execution or motor imagery. The behavioral results demonstrate that participants performed similarly on the task when they imagined vs. executed movements and this performance did not change over time. The fMRI results show a spatial overlap of MI and ME in a number of motor and premotor areas, sensory cortices, cerebellum, inferior frontal gyrus, and ventrolateral thalamus. MI uniquely engaged bilateral occipital areas, left parahippocampus, and other temporal and frontal areas, whereas ME yielded unique activity in motor and sensory areas, cerebellum, precuneus, and putamen. The MEG results show a robust event-related beta band desynchronization in the proximity of primary motor and premotor cortices during both ME and MI. Together, these results further elucidate the neural circuitry of MI and show that our task robustly and reliably invokes motor imagery, and thus may prove useful for interrogating the functional status of the motor circuitry in patients with motor disorders.
神经影像学研究表明，运动想象（MI）的神经机制与运动执行（ME）的机制有很大的重叠。然而，令人惊讶的是，运动回路的几个区域在 MI 中的作用仍然存在争议，这种变异性可能是由于神经影像学技术、MI 训练、指令类型或用于引发 MI 的任务的差异造成的。本研究的目的有两个：（i）设计一种新的任务，该任务能够可靠地引发 MI，提供 MI 表现的可靠行为测量，并可在不同的成像模式之间转换；（ii）使用功能磁共振成像（fMRI）和脑磁图（MEG）测量 MI 和 ME 的共同和差异激活。我们提出了一项任务，在没有运动执行或运动想象的情况下，很难给出准确的反应。行为学结果表明，参与者在想象和执行运动时在任务上表现相似，并且这种表现不会随时间而变化。fMRI 结果显示，在许多运动和运动前区域、感觉皮层、小脑、下外侧丘脑中，MI 和 ME 存在空间重叠。MI 仅在双侧枕叶区域、左侧海马旁回和其他颞叶和额叶区域中具有独特的激活，而 ME 在运动和感觉区域、小脑、顶下小叶和壳核中产生独特的活动。MEG 结果显示，在 ME 和 MI 期间，初级运动和运动前皮质附近存在强大的事件相关β频带去同步化。总之，这些结果进一步阐明了 MI 的神经回路，并表明我们的任务能够可靠地引发运动想象，因此可能有助于研究运动障碍患者的运动回路的功能状态。
