There are few studies using “normal” adult human drinkers who vary in their drinking levels (for a review, see Courtney & Polich, 2009). Ehlers and colleagues [28,31] assessed EEG in family history negative “low” and “moderate” drinkers (with drinking level determined by the quantity of alcohol consumption times the frequency of alcohol consumption). Moderate drinkers (scoring ≥ 40) evinced greater mean spectral power and higher peak frequency in the beta (12–20 Hz) band at baseline, so that beta activity may index quantity and frequency of alcohol consumption. Bruin et al. [32] quantified EEG synchronization in heavy drinking college students, defined as those who consume more than 30 units containing 12 gram of alcohol per week (≈ 30 ounces of hard alcohol). Functional connectivity during eyes closed recording differed between light and heavy drinkers, such that heavy drinkers exhibited abnormally increased synchronization in the theta (4–8 Hz) and gamma (30–45 Hz) bands as indexed by significant synchronization likelihood comparisons across groups. Both bands have been associated with memory formation as subserved by hippocampo-neocortical connections [33], and the synchronization of the heavy
