BACKGROUND Motor surround inhibition (mSI) is a phenomenon supportive for executing selective finger movements, wherein synergist muscles are selectively facilitated while surround muscles are inhibited. Previous studies of conditioning inputs to several intracortical and cortico-cortical inhibitory networks did not show an influence on mSI. The inhibitory posterior parietal-motor network, which is crucial for executing fine movements, however, has not been studied. OBJECTIVE/HYPOTHESIS To investigate the role of inhibitory posterior parietal-motor network in mSI. We hypothesized that conditioning this inhibitory network would enhance mSI. METHODS 11 healthy adults completed study. mSI was elicited by applying a TMS pulse over the motor cortex coupled with or without a conditioning input to an inhibitory spot in the posterior parietal cortex at 2 or 4 ms interval. RESULTS Conditioning input to the posterior parietal cortex increased mSI by ∼20% CONCLUSION: The inhibitory posterior parietal-motor network appears to contribute to the genesis of mSI.

中文翻译：

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顶叶调节增强运动环绕抑制

背景运动环绕抑制(mSI)是一种支持执行选择性手指运动的现象，其中协同肌被选择性地促进而环绕肌被抑制。先前对几个皮质内和皮质-皮质抑制网络的调节输入的研究并未显示出对 mSI 的影响。然而，对执行精细运动至关重要的抑制性后顶叶运动网络尚未得到研究。目的/假设 研究抑制性后顶叶运动网络在 mSI 中的作用。我们假设调节这种抑制网络会增强 mSI。方法 11 名健康成人完成研究。mSI 是通过在运动皮层上施加 TMS 脉冲而引发的，其中有或没有调节输入到后顶叶皮层中的抑制点，间隔为 2 或 4 毫秒。结果 后顶叶皮层的调节输入使 mSI 增加了约 20% 结论：抑制性后顶叶运动网络似乎有助于 mSI 的发生。