The role of the parietal cortex in perceptual awareness and in resolving perceptual ambiguity is unsettled. Early influential transcranial magnetic stimulation studies have revealed differences in conscious perception following parietal stimulation, fuelling the notion that parietal cortex causally contributes to resolving perceptual ambiguity. However, central to this conclusion is the reliability of the method employed. Several prior studies have revealed opposing effects, such as shortening, lengthening, or no effect on multistable perceptual transitions following parietal stimulation. Here we addressed the reliability of continuous theta-burst stimulation (cTBS) on parietal cortex on the perception of bistable stimuli. We conducted three cTBS experiments that were matched to prior experiments in terms of stimuli, stimulation protocol, and target site, and used a higher number of participants. None of our cTBS experiments replicated prior cTBS results. The only experiment using individual functional localizers led to weak effects, while the two others led to null results. Individual variability of motor cortex cTBS did not predict parietal cTBS effects. In view of recent reports of highly variable cTBS effects over motor cortex, our results suggest that cTBS is particularly unreliable in modulating bistable perception when applied over parietal cortex.

中文翻译：

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顶叶 theta 爆发 TMS 不会调节双稳态感知

顶叶皮层在知觉意识和解决知觉模糊性中的作用尚未确定。早期有影响力的经颅磁刺激研究揭示了顶叶刺激后意识知觉的差异，这强化了顶叶皮层因果关系有助于解决知觉模糊性的观点。然而，这一结论的核心是所采用方法的可靠性。先前的几项研究揭示了相反的影响，例如顶叶刺激后对多稳态知觉转变的缩短、延长或没有影响。在这里，我们讨论了顶叶皮层连续 theta 突发刺激 (cTBS) 对双稳态刺激感知的可靠性。我们进行了三项 cTBS 实验，这些实验在刺激、刺激方案和目标部位方面与之前的实验相匹配，并使用了更多的参与者。我们的 cTBS 实验均未复制之前的 cTBS 结果。唯一使用单个功能定位器的实验导致效果较弱，而其他两个则导致无效结果。运动皮层 cTBS 的个体差异并不能预测顶叶 cTBS 的影响。鉴于最近有关 cTBS 对运动皮层影响高度可变的报道，我们的结果表明，当应用于顶叶皮层时，cTBS 在调节双稳态感知方面特别不可靠。