Fig. 5.

Results of the summary Lmer model (Eq. (5)): A Estimated effects of the fixed factors as a forest plot for the summary model. The estimated value is given above each datapoint, and confidence intervals of the estimates given by horizontal lines. Significance of the effects is indicated by asterisks (‘${}^{\ast }$’: $p<0.05$, ‘${}^{\ast \ast }$’: $p\in <0.01$, ‘${}^{\ast \ast \ast }$’: $p<0.001$). Condition itself lacks a significant main effect, but shows significant interactions with ISI (B), left-hemispheric $\mu$-power (C) and right-hemispheric $\mu$-power (D). B Plot of the interaction of Condition and ISI (somewhat discrete, in steps of 0.1 s due to the implementation): The response in the FDI of the right hand is plotted against the normalized ISI. Each trial is represented by a dot colored by condition (red: high, blue: low). Additionally, the regression-lines (and confidence intervals) are given. C Interaction of Condition with the $\mu$-bandpower of the C3-Hjorth-signal (i.e. the left sensorimotor cortex): For low power, the effect of condition is indeed as expected (lower MEP amplitudes in the low compared to the high condition), but this flips for high power. D Interaction of Condition with the $\mu$-bandpower of the C4-Hjorth-signal (i.e. the left sensorimotor cortex): For high power, the effect of condition is as hypothesized (lower MEP amplitudes in the low compared to the high condition), the opposite holds for low right-hemispheric power. The $\mu$-power in the two hemispheres thus has opposite interactions with Condition.