The role of COMT Val158Met polymorphism impacts the performance in solving transitive inference problems

The Catechol-O-Methyl-Transferase (COMT) gene plays a crucial role in dopamine (Da) metabolism within the prefrontal cortex, exerting a direct impact on essential cognitive processes. This study aims to explore the influence of how the Val158Met polymorphism in the COMT gene impacts the solution of inferential problems through a transitive inference task. 83 participants were categorized into three COMT genotypes: Met/Met, Val/Val, and Val/Met. Initially, they were instructed to learn the relationships between adjacent pairs of items in a rank-ordered set (A>B>C>D>E>F) through trial and error. Subsequently, participants were asked to infer the higher-ranking items, not presented during the initial learning phase (e.g., C>E). The successful completion of this task is hypothesized to be dependent on the exploration of the mental schema of rank-ordered items, temporarily active in working memory and supported by prefrontal cortex functions. Analysis of task performance revealed that Val/Val participants exhibited significantly lower accuracy and longer response latency compared to Met/Met participants in solving inferential problems. These findings support the hypothesis that individuals with the Val allele have greater enzyme activity, resulting in a reduced prefrontal dopamine availability and consequent cognitive task efficiency. These results align with existing literature, highlighting the importance of the COMT gene in modulating cognitive functions, emphasizing the critical role of dopamine metabolism in the prefrontal cortex. Understanding these genetic influences contributes to a deeper comprehension of individual differences in cognitive abilities.