Figure 3.

Example of ECoG features from one subject. (A) 3D brain template with one location marked with a green star; (B) Normalized spectrogram of ECoG signals recorded at the location marked in (A), averaged across all spoken words with the same vowels, i.e., /i:/ (left) and /ε/ (right); (C) Distribution of samples in two-dimensional feature space (i.e., gamma and mu amplitudes marked with blue and red ellipses in (B), respectively) for vowels /i:/ (circles) and /ε/ (squares).