Brain Waves
State:
Focused (Beta)
Relaxed (Alpha)
Drowsy (Theta)
Deep Sleep (Delta)
REM Sleep
Noise
30%
Delta 0.5–4 Hz
Theta 4–8 Hz
Alpha 8–13 Hz
Beta 13–30 Hz
Gamma 30–100 Hz
EEG frequency bands reflect different brain states. Interference between channels shows how neural oscillations synchronize and desynchronize.