Fig. 5: Responses are modulated in a frequency-dependent manner.

a Examples of frequency-dependent modulation of muscular responses. EMG responses were elicited by 2 Hz stimulation of the IC paired with different VLL stimulation frequencies (10, 50, 80, 100, and 200 Hz). b The occurrence of modulation patterns with respect to stimulation frequency. All patterns recorded in all muscles of 3 animals were included in the analysis (n =  24 patterns at 10 Hz, n = 22 patterns at 50 Hz, n = 23 patterns at 80 Hz, n = 43 at 100 Hz, and n = 17 patterns at 200 Hz). c Top: Example of spinal responses in the ventral zone for IC stimulation alone and IC stimulation paired with VLL stimulation at 80 and 100 Hz (n = 30 traces per plot). Bottom: Heatmaps of the AUC calculated from 5 to 10 ms after IC stimulation for all ventral channels (CH 27–32 for MK-HS and CH: 26–31 for MK-JC) for IC stimulation alone and IC stimulation paired with VLL stimulation at 10, 50, 80, and 100 Hz. (*) for significant potentiation and (+) for significant suppression. Regular text represents p < 0.05; whereas bold represents p < 0.001. Statistical significance was tested by comparing IC stimulation alone to all other stimulation conditions for potentiation using one-tailed bootstrapping with Bonferroni correction. d Top: Schematic of the experimental layout for testing frequency dependence within the motor cortex. Bottom: Example traces of the cortical evoked potential responses in the M1 array when stimulating the thalamus at different frequencies (10, 50, 80, and 100 Hz) (n = 30 traces). Boxplots of the peak-to-peak amplitudes of the cortical evoked potentials. Statistical significance for (d) was tested by comparing 50 Hz VLL stimulation to all other stimulation conditions for potentiation using one-tailed bootstrapping with Bonferroni correction: p < 0.05 (*), p < 0.01 (**), p < 0.001(***). For all boxplots, the whiskers extend to the maximum spread not considering outliers. Central, top, and bottom lines represent median, 25th, and 75th percentile, respectively. Source data for (b–d) are provided as a Source Data file. The spinal cord and the brain in (c, d) were created with BioRender.com released under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International license.