(A) Position of TMS targeting. (B) Schematics of the TMS study design. The electroencephalogram (EMG) trace showed is for illustrative purpose only. (C) Averaged measurements of motor threshold. Data are represented as mean ± SD (in shaded areas). ANOVA test was applied to test the differences among timepoints; p-value is showed when statistically significant. (D) Distribution of the correlation coefficients between individuals’ sleepiness scores and motor threshold measurements (median in red line, 25% and 75% quantiles in dotted lines). One-sample t-test was used to compare the distribution to 0; p-value is showed when statistically significant. Equivalent to the formats of (C) and (D), later panels show data for motor-evoked potentials latencies (E, F), short interval intracortical facilitations (SICFs) (H, I), short interval intracortical inhibitions (SICIs) (K, L), intracortical facilitations (ICFs) (N, O), and long interval intracortical inhibition (LICI) (Q, R). For the four pair-pulse protocols, a schematic is showed for the respective protocol, (G) SICF, (J) SICI, (M) ICF, and (P) LICI. For all TMS measurements, N = 38 except for LICI (Q, R, N = 15, Figure 1—figure supplement 1). Statistical comparisons between sessions are reported in Figure 1—figure supplement 2.