Inheritance of neural substrates for motivation and pleasure experience

Despite advances in the understanding of the reward system and the role of dopamine in recent decades, the heredity of the underlying neural mechanisms is not known. In the present study, a Monetary Incentive Delay (MID) task was used to examine the haemodynamic activation of the nucleus accumbens (NAcc), a key hub of the reward system, in 86 healthy monozygotic twins and 88 dizygotic twins during the anticipation of monetary incentives. The participants also completed self-report measures of pleasure experience. Using a voxel-wise heritability mapping method, activation of the bilateral NAcc during the anticipation of monetary gains was found to have significant heritability (h2 = 0.20-0.49). Moreover, significant shared genetic covariance was observed between pleasure experience and NAcc activation when anticipating monetary gain. These findings suggest that NAcc activation and self-reported pleasure experience may both be heritable, and their phenotypic correlation may be partially explained by shared genetic variation.