Spectral profiles.

For each animal, the averaged frequency spectrum of the EEG recording (its spectral profile) was computed per vigilance class. Each plot in the left column is related to one of the 4 animal cohorts and consists of the mean spectral profile curve and the corresponding standard deviation (a half of it). All curves are normalized relative to the total power of the signal. The middle and the right column respectively represent coarse-grained (following the classical delta, theta, sigma and beta bands) and fine-grained histogram binning applied to the raw spectral profiles, with bars representing summed spectral power in each bin.