ABSTRACT
Effectivc decision-making involves working memory and exccutive function, which depend on the efficiency of dopamine signaling in prefrontal cortex. We examined associations bctween two single nucleotide polymorphisms (SNPs) in the dopamine hydroxylase (DBB) gene, 444 G/A and - 1 02 1 CIT, and individual differences in working memory and decision-making. The IT allele of the - 1 02 1 C/I SNP leads to a 1 0-fold decrease in plasma enzyme level (DEB) and a comparable increase in synaptic dopamine, compared to the CC allele. The working memory task involved maintaining up to three spatial locations over a period of 3 s. The decision-making task involved simulated coll1ll1and and control (C2) and required pal1icipants to identify and engage critical enemy units, with or without the assistance of automation, within 1 0 s. Working memory accuracy was significantly greater for the TT allele than for either the TC or CC alleles. Compared to a high DEB enzyme group, a low DEB enzyme (high synaptic dopamine) group made decisions on the C2 task more rapidly and were less affected by automation unreliability. The results show that the DBB gene is associated with individual variation in working memory capacity and with speeded decision making under time pressure. Both findings are consistent with a prominent role for pre frontally modulated working memory processes in decision making.
