Lack of association between the 5-HTTLPR and the error-related negativity (ERN)

The error-related negativity (ERN) is a negative waveform that occurs approximately 50ms after an incorrect response. Pharmacological manipulations and theoretical accounts suggest that the ERN reflects reward-related dopamine activity; however, it is likely that several neurotransmitters contribute to the generation of the ERN. Two studies have found an association between the ERN and the serotonin transporter-linked promoter region (5-HTTLPR) polymorphism. In order to investigate this further, 86 participants performed an arrow version of the flanker task and were genotyped for the 5-HTTLPR and the A/G SNP (rs25531) located within the L allele. Despite using multiple methods to group subjects by genotype and score the ERN, no reliable associations between the ERN and the 5-HTTLPR were found. The current study casts doubt on the relationship between ERN and 5-HTTLPR; reasons for this discrepancy with previous work are discussed.