Somatosensory stimulation can effectively induce plasticity in the motor cortex representation of the stimulated body part. Specific interactions have been reported between different representations within the primary motor cortex. However, studies evaluating somatosensory stimulation-induced plasticity between different representations within the primary motor cortex are sparse. The purpose of this study was to investigate the effect of somatosensory stimulation on the modulation of plasticity between different representations within the primary motor cortex. Twelve healthy volunteers received both electroacupuncture (EA) and sham EA at the TE5 acupoint (located on the forearm). Plasticity changes in different representations, including the map volume, map area, and centre of gravity (COG) were evaluated by transcranial magnetic stimulation (TMS) before and after the intervention. EA significantly increased the map volume of the forearm and hand representations compared to those of sham EA and significantly reduced the map volume of the face representation compared to that before EA. No significant change was found in the map volume of the upper arm and leg representations after EA, and likewise, no significant changes in map area and COG were observed. These results suggest that EA functions as a form of somatosensory stimulation to effectively induce plasticity between different representations within the primary motor cortex, which may be related to the extensive horizontal intrinsic connectivity between different representations. The cortical plasticity induced by somatosensory stimulation might be purposefully used to modulate human cortical function.

中文翻译：

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电针诱导的人体运动皮层不同表现之间的可塑性。

体感刺激可以有效地诱导受刺激身体部位运动皮层表征的可塑性。已经报道了初级运动皮层内不同表征之间的特定相互作用。然而，评估初级运动皮层内不同表征之间的体感刺激诱导的可塑性的研究很少。本研究的目的是研究体感刺激对初级运动皮层内不同表征之间可塑性调节的影响。十二名健康志愿者在 TE5 穴位（位于前臂）接受电针 (EA) 和假电针。不同表示的可塑性变化，包括地图体积、地图面积、在干预前后通过经颅磁刺激（TMS）评估重心（COG）。与假 EA 相比，EA 显着增加了前臂和手部表征的地图体积，并与 EA 之前相比，显着减少了面部表征的地图体积。EA 后上臂和腿部表示的地图体积未发现显着变化，同样，未观察到地图面积和 COG 的显着变化。这些结果表明 EA 作为体感刺激的一种形式，可以有效地诱导初级运动皮层内不同表征之间的可塑性，这可能与不同表征之间广泛的水平内在连接有关。