Differential effects of 5-HTTLPR and DRD2/ANKK1 polymorphisms on electrocortical measures of error and feedback processing in children.

OBJECTIVE

Applying a probabilistic learning task we examined the influence of functional polymorphisms of the serotonin transporter gene (5-HTTLPR) and the D2 dopamine receptor gene (DRD2/ANKK1) on error and feedback processing by measuring electrocortical event-related potentials (ERPs) in 10- to 12-year-old children.

METHODS

Three pairwise group comparisons were conducted on four distinguishable ERP components, two of which were response-related, the other two feedback-related.

RESULTS

Our ERP data revealed that children carrying the short (S) variant of the 5-HTTLPR gene process their errors more intensively while exhibiting less habituation to negative feedback with task progression compared to children who are homozygous for the 5-HTTLPR long (L) variant. Children possessing the Taq1 A variant of the DRD2 gene showed greater sensitivity to negative feedback and, as opposed to Taq1 A non-carriers, a diminishing sensitivity to positive feedback with task progression. Regarding error processing, children possessing both the S variant of the 5-HTTLPR and the Taq1 A allele of the DRD2 gene showed a picture quite similar to that of the 5-HTTLPR S carriers and regarding feedback processing quite similar to that of the DRD2 Taq1 A carriers.

CONCLUSIONS

Our findings support the hypotheses that the 5-HTTLPR S allele may predispose to (performance) anxiety, while DRD2 Taq1 A allele may predispose to the reward deficiency syndrome.

SIGNIFICANCE

The results may further enhance our understanding of known associations between these polymorphisms and psychopathology.