The human scalp EEG represents the ongoing electrophysiological signals in a continuous fashion, and can be recorded during several mental states: eyes-closed relaxed state, eyes-open steady state, meditation, hypnosis, sleep, coma, and other normal/altered states of consciousness [45]. Traditionally, EEG can be decomposed into different frequency bands, most commonly: delta (0-3.5 Hz), theta (4-7.5 Hz), alpha (8-12.5 Hz), beta (13-28.5 Hz) and gamma (> 29 Hz), and each of these bands are assumed to reflect different types of brain activity. One of the robust and consistent resting EEG findings in alcoholism is that alcoholics and their high-risk offspring show increased beta band activity [46-50].
