Dopamine-related polymorphisms and affective working memory in aging

The neurotransmitter dopamine (DA) is a key regulatory component of executive functioning and dysfunction in dopaminergic circuity has been shown to result in impaired working memory. Studies have identified multiple common genetic variants suggested to functionally impact the DA system and behaviorally alter working memory performance. Here, we aimed to develop a predictive model of affective working memory and to examine whether specific combinations of polymorphisms differently influence later encoding processes in affective working memory. Specifically, we examined the effects of the dopamine D2 and D1 receptors and Catechol-O-methyltransferase (COMT), on affective working memory in 155 older adults. Our model identified genotype variants, and scores on the Mini-Mental State exam and Geriatric depression scales as significant influencers in the predictive model whereas behavioral results showed specific patterns of performance linked to valence and string length but not to specific genetic variants. That is, all participants remembered a more positive words compared to negative and neutral words when remembering short strings of 3 or 4 words whereas performance on long strings, 5 or 6 words, revealed a more general affective enhancement independent of genotype. These findings are some of the first to investigate the effects dopaminergic enzyme and receptor interactions on affective working memory.