Fig. 3.

Group differences in brain response during the choice phase. The blue clusters comprise contiguous voxels where high-risk twins displayed an attenuated increase in choice-related activity with higher gambling risk relative to low-risk twins. Reduced risk-related activity was located in the middle part of the insula extending into the superior temporal cortex. The green clusters are regions in the insula showing an interaction effect between familial risk and zygosity. There was a reduced influence of risk on choice-related activity in dizygotic high-risk twins as opposed to dizygotic low-risk twins, but no such difference was present in the monozygotic group. The red clusters show a risk-related increase in the insula’s response during the choice phase across all participants. For all clusters, we applied an extent threshold of p < 0.005, uncorrected.