Mean age across genotype groups [AA = 19.29; AG = 19.25; GG = 19.41] was not significantly different. Significant main and interaction effects extracted from the ANOVA results have been presented in Table 2 and Fig. 3. There was a significant main effect of genotype showing an additive effect with increase in theta power corresponding to the number of minor alleles (GG > AG > AA <=> 2.82 > 2.74 > 2.70) [see Table 2]. The significant main effect of condition revealed that the gain condition (M = 2.79; SE = 0.02) displayed higher theta power than the loss condition (M = 2.71; SE = 0.02). The region main effect indicated that the parietal region had the highest theta power (M = 2.79; SE = 0.02) followed by central (M = 2.77; SE = 0.02) and frontal regions (M = 2.70; SE = 0.02). Genotype × region interaction effect indicated that theta differences between genotypes (GG > AA) were significant in central (2.84 > 2.71) and parietal (2.88 > 2.72) but not in frontal region (2.73 vs 2.68). Genotype ×
