Across a series of studies, our lab has shown that the efficiency of action stopping is associated with the strength of GABAA-mediated short-intracortical inhibition (SICI) as measured using transcranial magnetic stimulation (TMS). However, these studies used fixed TMS parameters, which may not optimally probe GABAA receptor activity for each individual. In the present study, we measured the relationship between stopping efficiency and SICI using a range of TMS parameters. Participants completed a right-hand unimanual stop signal task to obtain a measure of stopping efficiency. Resting-state SICI was measured from the left primary motor cortex using six combinations of interstimulus intervals and conditioning pulse intensities. We also established the parameters which generated the strongest SICI (SICImax) and weakest SICI (SICImin) for each individual. We found that stopping efficiency was significantly predicted by SICI using various TMS parameters, including SICImax. Interestingly, SICImin accounted for a similar proportion of variance in stopping efficiency as SICI measured using other TMS parameters. The findings suggest that the relationship between stopping efficiency and SICI is robust, reliable, and not influenced by the extent to which SICI is optimally probed.

中文翻译：

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将皮质和行为抑制联系起来：测试经颅磁刺激方案的参数特异性

在一系列研究中，我们的实验室表明，使用经颅磁刺激 (TMS) 测量，动作停止的效率与 GABAA 介导的短皮质内抑制 (SICI) 的强度有关。然而，这些研究使用了固定的 TMS 参数，这可能无法最佳地探测每个人的 GABAA 受体活性。在本研究中，我们使用一系列 TMS 参数测量了停止效率和 SICI 之间的关系。参与者完成了右手单手停止信号任务，以获得停止效率的衡量标准。使用刺激间隔和调节脉冲强度的六种组合从左侧初级运动皮层测量静息状态 SICI。我们还建立了为每个个体生成最强 SICI (SICImax) 和最弱 SICI (SICImin) 的参数。我们发现 SICI 使用各种 TMS 参数（包括 SICImax）显着预测了停止效率。有趣的是，SICImin 在停止效率方面的方差比例与使用其他 TMS 参数测量的 SICI 相似。研究结果表明，停止效率和 SICI 之间的关系是稳健、可靠的，并且不受 SICI 最佳探测程度的影响。