Fig. 4: The direction of the relationship between β power and performance-related motor variables was reversed depending on task instruction in EXP2.

A, D, G Schematic illustration of expected results according to the motor vigor (left) and motor flexibility (right) hypotheses. Red and cyan curves indicate expected linear associations in Fast and Slow, respectively. B, E, H Left, linear regression lines from LME models between β power and each motor variable tested (B: |Acc | , E: RT, H: MT) and NF condition (blue: β-down, orange: β-up, gray: Sham-Passive) and averaged across NF conditions in Fast (left plot, red line) and Slow (right plot, cyan line). Slope values of each line and their respective 95% confidence intervals are written on top of each plot, with p-value from one-sample t test of mean slope against zero. Right, distribution of single trial values of each motor variable. Fast trials are represented in red and Slow trials in cyan. Mean (µ) and standard deviations (σ) of distributions are written on the right of each panel in Fast (red) and Slow (cyan) separately. C, F, I Slope estimates of the association found between signal power and motor variables in LME models at each 1 Hz frequency band between 8 and 35 Hz. Red and cyan curves represent results in Fast and Slow, respectively. In all plots, shaded areas illustrate 95% confidence intervals. Confidence intervals that do not include zero correspond to statistically significant p values (p < 0.05), while those that include zero are not significant.