Focusing on neurocognitive aspects of AUDs, other groups have investigated the neuroelectric endophenotype of frontal theta reward event related oscillations (EROs) in addition to clinical diagnoses or self-reported measures (Klimesch et al., 2001), (Kamarajan et al., 2006), (Kang et al., 2012). Theta EROs are implicated in inhibitory control, conscious awareness, episodic and recognition memory, and evaluating loss and gain in gambling paradigms (Klimesch et al., 2001). Decrease in reward response theta EROs is a highly heritable endophenotype observed in AUD patients and their adolescent offspring at risk for the disorder (Kamarajan et al., 2006). A family-based study of theta EROs in AUD patients, their offspring, and healthy controls identified several polymorphisms in the KCNJ6 gene, with the most significant SNP (rs702859, imputed) at p = 4.7×10−10 constituting a synonymous mutation in exon 4 and other genotyped and imputed SNPs located in intronic regions (Kang et al., 2012). KCNJ6 encodes the G protein-gated inwardly rectifying potassium channel GIRK2, which plays an important role in regulating neuronal excitability by stabilizing the membrane potential (Lüscher and Slesinger, 2010). KCNJ6 is expressed in cholinergic,
