Studies with alcoholics and their offspring have consistently reported ERO deficits in delta, theta, and gamma bands in visual oddball tasks. Furthermore, deficits in theta ERO power have been reported across several task paradigms (e.g., oddball, Go/NoGo, and gambling) in these groups. Since theta ERO contributions to the P3 as well as N2 components of the ERP are mainly from frontocentral regions of the brain, it can be hypothesized that the deficits in theta ERO power in these groups may be associated with the dysfunctional frontal processing. Further, these frontal theta ERO deficits in the offspring of alcoholics indicate that they antecede the development of alcoholism. Importantly, the frontal theta EROs have successfully served as endophenotypes in genetic studies of alcoholism, and have been found to be significantly associated with SNPs in CHRM2 [179,180], GRM8 [198], and HTR7 [216] genes, SNPs that have also been found to be significantly associated with alcohol dependence. This suggests the involvement of glutamatergic, GABAergic and serotonergic systems in the modulation of theta oscillations especially in the context of alcoholism.
