Neurology Research Group, Department of Medicine, University of Auckland, Auckland, New Zealand.
PLoS One. 2012;7(5):e37850. doi: 10.1371/journal.pone.0037850. Epub 2012 May 31.
Both mental rotation (MR) and motor imagery (MI) involve an internalization of movement within motor and parietal cortex. Transcranial magnetic stimulation (TMS) techniques allow for a task-dependent investigation of the interhemispheric interaction between these areas. We used image-guided dual-coil TMS to investigate interactions between right inferior parietal lobe (rIPL) and left primary motor cortex (M1) in 11 healthy participants. They performed MI (right index-thumb pinching in time with a 1 Hz metronome) or hand MR tasks, while motor evoked potentials (MEPs) were recorded from right first dorsal interosseous. At rest, rIPL conditioning 6 ms prior to M1 stimulation facilitated MEPs in all participants, whereas this facilitation was abolished during MR. While rIPL conditioning 12 ms prior to M1 stimulation had no effect on MEPs at rest, it suppressed corticomotor excitability during MI. These results support the idea that rIPL forms part of a distinct inhibitory network that may prevent unwanted movement during imagery tasks.
心理旋转（MR）和运动想象（MI）都涉及运动在运动和顶叶皮层内的内化。经颅磁刺激（TMS）技术允许在任务相关的情况下研究这些区域之间的半球间相互作用。我们使用图像引导的双线圈 TMS 来研究 11 名健康参与者中右顶下小叶（rIPL）和左初级运动皮层（M1）之间的相互作用。他们进行 MI（右手食指和拇指在 1 Hz 节拍器的时间内捏合）或手 MR 任务，同时记录右第一背间骨间肌的运动诱发电位（MEP）。在休息时，M1 刺激前 6ms 的 rIPL 条件刺激在所有参与者中均促进了 MEP，而在 MR 时这种促进作用被消除。虽然 rIPL 在 M1 刺激前 12ms 条件刺激对休息时的 MEP 没有影响，但它抑制了 MI 期间的皮质运动兴奋性。这些结果支持了 rIPL 形成一个独特的抑制性网络的观点，该网络可能在想象任务期间防止不必要的运动。
