Main effect of age group, as shown in Table 3, indicated that younger subjects [3.24 (0.02)] displayed significantly higher theta power [F = 163.81; p < 0.0001] than older subjects [2.83 (0.02)] in general, and in all or most of the comparisons within the subgroups (see Fig 3, panel sets C1 and C2). Age group × condition effect showed that the younger group displayed significantly higher theta power during loss [younger = 3.21 (0.02); older = 2.76 (0.03); F = 173.85; p < 0.0001] as well as during the gain condition [younger = 3.26 (0.02); older = 2.90 (0.03); F = 117.33; p < 0.0001]. The same interaction effect also revealed that significant condition differences (gain > loss) were more robust in the older age group [F = 68.21; p < 0.0001] than in the younger group [F = 13.30; p = 0.0003]. On the other hand, age group × region interaction effect showed that while the difference in theta power between the younger and the older age group was significant in all four regions (younger > older), the highest
