The sample of human EEG with prominent resting state activity - alpha-rhythm. Left - EEG traces (horizontal - time in seconds; vertical - amplitudes, scale 100uV). Right - power spectra of shown signals (vertical lines - 10 and 20Hz, scale is linear). Alpha-rhythm consists of sinusoidal-like waves with frequencies in 8-12Hz range (11Hz in this case) more prominent in posterior sites. Alpha range is red at power spectrum graph.