Journal of Undergraduate Research


polymorphisms, 5-HTTLPR gene, ERN, depression


Life Sciences




Our aim with this study of polymorphisms in the serotonin transporter gene (5-HTTLPR) was to investigate the association between performance monitoring capabilities (i.e., detecting errors in performance using the error-related negativity [ERN] component of the scalp recorded event-related potential [ERP]) against three variations of gene 5-HTTLPR allelic pairs: homozygous short (S/S), heterozygous short-long (S/L), and homozygous long (L/L). The serotonin transporter gene is associated with our ability to cope with stress and regulate serotonin, which affects mood, social behavior, appetite, and sleep (Adam, Doane, Zinbarg, Mineka, Craske, & Griffith, 2010). Previous studies (Barnes, Dean, Nandam, O’Connell, & Bellgrove, 2011) have investigated the relationship between increased-amplitude ERN and the S/S and S/L polymorphism when compared to the L/L allelic pair. Some findings have has associated the short allele with a decreased ability to cope with stress while others have negated that relationship (Starr, Hammen, Brennan, Najman, 2012; Barnes, Dean, Nandam, O’Connell, & Bellgrove, 2011; de Brujin, Sabbe, Hulstiijn, Ruigt, & Verkes, 2006; Fallgatter, Herrmann, Roemmler, Ehlis, et. Al 2004). Our study was important because we made two key changes: we controlled for a L/L SNP variation that frequently behaves like the short allele (Caspi, Sugden, Moffitt, et. Al 2003) and we used a sample size that would help us achieve more conclusive results. Our hypothesis was that while accounting for the long A/G SNP variation, we would test the relationship between short/long allelic pairs in the 5-HTTLPR polymorphism and an increase in performance monitoring when a short allele is present when compared to homozygous long alleles to attempt to demonstrate that there would be no significant difference between S/S, S/L, and L/L allelic variations and increased ERN.