The major findings of the current study are 1) an additive genotypic effect of the KCNJ6 SNP on the ERO theta power phenotype during reward processing, increasing significantly across genotypes (GG > AG > AA) in central and parietal regions in both loss and gain conditions, and 2) genotypic effect on scalp topography of theta ERO phenotype during reward processing, with an anterior topography in those with the dominant AA genotype during loss evaluation not present in the AG and GG genotypes, while the ‘anterior – posterior’ effect was strongest in GG followed by AG and AA genotypes during gain processing. Our current study extends the previous findings showing an association between KCNJ6 gene polymorphisms and theta ERO phenotypes to targets in an oddball task to an association with theta EROs during reward processing.
