Fig. 6. Relationship between antidromic volley (ADV) area and potential oscillatory motor output.

a Grand average of the power spectrogram (n = 77 ADVs) for wrist torque during extension (top) and flexion (bottom). The fast Fourier transformation (FFT) spectrogram for each trial was categorized by ADV area during the static task epoch and averaged for each ADV. Red and black lines, averages of the small and large ADV trials, respectively (n = 77 ADVs). The torque signals just after movement onset (0–1 s after movement onset) were analysed. A small peak in the range of physiological oscillations was noted (5–20 Hz), but there was no significant difference between the large and small trials at any frequency (two-tailed paired t-tests with Bonferroni’s correction, correction size = 60, n = 77 ADVs, ps > 0.05). b Lag and correlation coefficient of the second peak from the autocorrelation of wrist torque (0.3–1 s after movement onset). The second peaks were detected from trial-based autocorrelations, which were observed within 25–350 ms from lag 0 and whose correlation coefficients were >0.3. According to trial categorization, open black circles indicate that the data were obtained from large ADV trials and closed red circles indicate they were from small ADV trials. Only a few trials (<3.3%) showed second peaks. No significant differences were observed between the large and small ADV trials in mean lag or mean coefficient (two-tailed t-tests, extension, lag, p = 0.810, correlation coefficient, p = 0.611, df = 242 trials; flexion, lag, p = 0.180, correlation coefficient, p = 0.769, df = 111 trials). c Grand average of the power spectrogram for electromyography (EMG) traces (extensor digitorum-2,3 [ED23] and flexor digitorum superficialis [FDS]) calculated in the same way as in (a). No significant difference between trials was found at any frequency (two-tailed paired t-tests with Bonferroni’s correction, correction size = 60, n = 77 ADVs, ps > 0.05). Source data are provided as a Source data file.