Delta : 1 ~ 4 Hz - Deep sleep, regenerative effects, loss of bodily awareness
Theta : 4 ~ 8 Hz - Dream state, deep meditation, intuitive awareness, REM sleep
Alpha : 8 ~ 14 Hz - Awake, focussed on inner world, relaxation
Beta : 14 ~ 40 Hz - Awake, focused on outer world, learning, productiveness.