Cortico-muscular coherence and power spectra of EEG and rectified EMG in pre-training condition. Top row shows EEG power spectra from the left EEG (Panel A) and the right EEG (Panel B). Middle row shows the power spectrum of rectified EMG recorded from the right ECR muscle (Panel C). Bottom row shows coherence between EEG and rectified EMG of the right ECR. The horizontal lines denote the 99% confidence limit. Panels D and E show the Laplacian EEG from the left and right hemispheres, respectively.