The results confirmed GABAA signaling as being involved in fast oscillatory (beta) activity in the full meta‐analysis (p = .024); however, it failed to reach significance after removing COGA, the discovery sample (p = .052). Interestingly, the Metaxcan expression analysis significantly associated hippocampal GABRA2 expression to beta oscillations (p = .0024 and p = .0050 without COGA). This latter result fits well with observations that beta oscillations are influenced by GABAA receptor\alpha 2 agonists such as benzodiapines (van Lier et al., 2004; Manmaru & Matsuura, 1989; Montagu, 1972), and the crucial role of GABAA interneurons for synchronized fast rhythms in the brain (Buzsáki & Chrobak, 1995). In our view, there is now evidence that hippocampal GABA functioning mediates the relation between resting‐state EEG beta power and alcohol dependence (Dick et al., 2006; Edenberg et al., 2004; Rangaswamy et al., 2002). The selective hippocampal expression association suggests that the genetic variants affecting beta oscillations also affect hippocampal GABAA receptor's sensitivity to interneuron inhibition. Together, these results indicate that the association between GABRA2 and beta oscillations is more difficult to detect in
