Epistasis effects of dopamine genes on interval timing and reward magnitude in humans

► We investigated the effect of reward on timing behavior using the peak procedure. ► We also investigated its interaction with COMT, DRD2, and DAT gene polymorphisms. ► Results show earlier timed response initiations when expecting larger rewards. ► This effect was specific to certain COMT-DRD2 polymorphism combinations. ► There was no effect of DAT gene polymorphisms.