Fig. 6: Effects of online TUS and masking assessment.

A TUS after-effect assessment on sham trials (n = 35). Each sham trial was labeled based on the preceding trial’s stimulation condition (e.g., “L FEF → sham” indicates a sham trial following left FEF stimulation). Density clouds represent participant distributions of saccade bias on sham trials that followed stimulation trials; dots represent group mean; error bars represent the standard error of the mean (S.E.M.). *p < 0.05, ns p > 0.1. Participants made significantly more ipsilateral saccades on sham trials following stimulation, but importantly and unlike the main TUS effect, this effect was not specific to FEF. B Masking, perceived stimulation (yes/no). Probability of reported stimulation perception across sham, FEF, and M1 conditions (n = 34). Density clouds represent participant distributions, bars indicate group means, and error bars show the S.E.M. ***p < 0.001, ns p > 0.1. Participants were significantly more likely to perceive stimulation during TUS trials compared to sham trials, highlighting that sham conditions alone may not fully account for TUS effects. No significant difference was observed between FEF and M1 conditions. C Masking, perceived stimulation side (left/right). Probability of reported stimulation side perception in the masking assessment (n = 34). Density clouds represent participant distributions, dots represent group means, and error bars show the S.E.M. **p < 0.01, ns p > 0.1. Participants were more likely to perceive TUS contralateral to the actual stimulation site. This effect was consistent across FEF and M1 regions, as indicated by the absence of a significant side-by-region interaction, supporting the robustness of the active control design. A–C Source data are provided as a Source Data file. Exact p values are presented in the main text. Statistical significance was determined using two-sided logistic mixed effects regressions. No multiple comparisons were applied.