Our analyses of EEG-specific candidate genes corroborated Derringer et al. (2011) in failing to replicate the finding of an association between SGIP1 and theta power (Hodgkinson et al., 2010). Perhaps our most compelling gene-related finding was an association between beta power and the GABRA2 gene, which has been reported previously by two independent groups (Edenberg et al., 2004; Lydall et al., 2011; Rangaswamy et al., 2002). We specifically found an association between the G allele of rs279858, a synonymous exonic variant in GABRA2, and reduced beta power. This allele tags a haplotype that confers risk for heavy drinking and an early onset of alcohol dependence (Enoch, 2008). Our finding is thus consistent with evidence that beta power is reduced in alcohol dependence and related disinhibitory psychopathology. As others have indicated, GABRA2 is a plausible candidate for association with beta power in particular. GABRA2 encodes the α2 subunit of the GABAA receptor, and inhibitory GABAergic interneurons are centrally involved in producing high frequency oscillations, particularly those in the beta and gamma range. The specific frequency of oscillations in neuronal networks is
