Poster C108, Sunday, March 26, 5:00 – 7:00 pm, Pacific Concourse
Additive effects of two dopamine modulating genes on feedback-based cognitive sequence learning in younger adults
Sylvia Larson1, Angelica Boeve1, Mark Gluck2, Jessica Petok1; 1Saint Olaf College, 2Rutgers University
Complex sequences of behaviors can be mastered via backwards chaining, where smaller associations are learned in a step-wise fashion in order to acquire the entire sequence of actions. Dopamine supports this type of learning, and research has shown that variations in the dopamine transporter gene (DAT1), which play a role in striatal dopamine availability, influence such feedback-based sequence learning. A polymorphism in the catechol-O-methyltransferase (COMT) gene, which predicts frontostriatal dopamine availability, has also been shown to influence learning during sequencing tasks. Here, we examined whether COMT may interact with DAT1 to influence learning of associations. Participants, grouped by COMT (Val homozygotes and Met-carriers) and DAT1 genotype (9-repeat carriers and 10 homozygotes), completed a backward feedback-based ‘chaining’ task. With increasing task complexity, COMT status interacted with DAT1; 9-repeat carriers’ performance did not change depending on COMT polymorphism whereas, among the 10 homozygotes, fewer Val homozygotes were able to reach criterion relative to Met-carriers. Including only participants who completed the chaining task, performance of 9-repeat carriers differed by COMT status, whereby 9-repeat carrier Val homozygotes made more errors relative to 9-repeat carrier Met-carriers. COMT status did not have a significant effect on 10 homozygotes’ performance. Of note, there were no significant effects or interactions of genotype for performance on a retest phase, which ensures participants’ ability to learn single associations and rules out the fatigue effect. Results demonstrate additive effects of genes regulating dopamine availability in the prefrontal cortex and striatum on feedback-based sequence learning.
Topic Area: LONG-TERM MEMORY: Skill learning