Effects of within-subjects factors (condition × region, condition, and region) were highly significant (p < 0.001). Condition × region interaction indicated that P3 was larger in the gain compared to the loss condition in all regions, and this observation was further confirmed by the condition main effect. The region main effect showed that overall P3 amplitude was highest in the parietal region, followed by central, occipital and frontal regions (i.e., parietal > central > occipital > frontal), thus indicating that P3 scalp voltage has a posterior topography.
