Figure 5. Effects of ultrasound parameters on TMS-induced resting peak-to-peak motor-evoked potential (MEP) amplitudes as measured by FDI EMG (N = 16).

Means of MEPs were plotted across the different sub-experiments which varied different parameters (A) Duty cycle (p=0.015; RM one-way ANOVA), 10% DC suppressed MEPs compared to sham (p=0.027, paired t-test). (B) Sonication duration had an effect proportional to the length of sonication (p<0.001; RM one-way ANOVA), with significant suppression compared to sham with 0.4 s (p=0.003), and 0.5 s (p=0.004). (C) Varying the pulse repetition frequency with fixed DC (p=0.08; RM one-way ANOVA) or (D) adjusted DC to keep constant burst duration (p=0.31; RM one-way ANOVA) did not have a significant effect. Error bars represent standard error. Asterisks are indicative of a significant post-hoc two-tailed paired t-test, and p-values are adjusted with the Holm-Bonferroni method (α = 0.05).

Figure 5—figure supplement 1. Effects of blocked and interleaved variation of ultrasound parameters on TMS-induced resting peak-to-peak MEP amplitudes as measured by FDI EMG (N = 16).

Medians of MEPs were plotted across the different sub-experiments: (A) Interleaved Duty cycle (p=0.02; RM one-way ANOVA), 10% DC suppressed MEPs compared to sham. (B) Blocked Duty cycle (p<0.0001; RM one-way ANOVA), both 10% and 30% DC suppressed MEPs compared to sham. (C) Interleaving the pulse repetition frequency with constant DC parameters did not result in significant differences from sham (p=0.122; RM one-way ANOVA), but doing so in a blocked paradigm (D) resulted in significant suppression of MEPs compared to sham (p<0.001; RM one-way ANOVA) for 200, 500, and 1000 Hz. (E) Interleaving the pulse repetition frequency with adjusted DC parameters did not result in significant differences from sham (p=0.648; RM one-way ANOVA), but doing so in a blocked paradigm (F) resulted in significant suppression of MEPs compared to sham (p=0.003; RM one-way ANOVA) for 200, 500, and 1000 Hz. Error bars represent standard error. Asterisks are indicative of a significant post-hoc two-tailed paired t-test, and p-values are adjusted with the Holm-Bonferroni method (α = 0.05).

Figure 5—figure supplement 2. Post-hoc analysis of blocked delivery of ultrasound parameters by trial number (N = 16).

The left panels plot the mean TMS-induced resting peak-to-peak MEP amplitudes stratified by trial number within the block for the three parameter condition sets tested. The right panels compare early to late trials across conditions. In the blocked Duty Cycle experiment, no significant differences between early and late trials were found in the sham, 10%, 30%, or 50% conditions (p=0.31, 0.31, 0.81,0.81, paired t-tests). Similarly, in the blocked PRF experiments, no differences were found between early and late trials within the sham, 100, 500, or 1000 Hz conditions when DC was held constant (p=0.09, 1.0, 1.0, 1.0, paired t-tests) or adjusted (p=0.92, 1.0, 1.0, 1.0, paired t-tests). Error bars represent standard error, and p-values are adjusted with the Holm-Bonferroni method (α = 0.05).