RESUMO
Genetic differences in the dopamine and serotonin systems have been suggested as potential factors underlying interindividual variability in risk taking and in brain activation during the processing of feedback. Here, we studied the effects of dopaminergic (dopamine transporter [DAT1], catecholamine-O-methyltransferase val158met [COMT]) and serotonergic (serotonin transporter [5HTTLPR]) polymorphisms on risk taking and brain responses following feedback in 60 healthy female subjects. The subjects completed a well-established experimental gambling paradigm while an electroencephalogram was recorded. During the task, risk-taking behavior and prefrontal brain responses (feedback-related negativity [FRN]) following monetary gains and losses were assessed. FRN amplitudes were enhanced for nine-repeat-allele carriers of the DAT1 and short-allele carriers of 5HTTLPR, which are both presumably linked to less transporter activity and higher neurotransmitter levels. Moreover, nine-repeat DAT1 carriers displayed a trend toward increased risk taking in general, whereas 5HTTLPR short-allele carriers showed decreased risk taking following gains. COMT val158met genotype was unrelated to FRN amplitude and average risk taking. However, COMT met/met carriers showed a pronounced feedback P3 amplitude independent of valence, and a gradual increase in risk taking during the gambling task. In sum, the present findings underline the importance of genetic variability in the dopamine and serotonin systems regarding the neurophysiology of feedback processing.
Assuntos
Catecol O-Metiltransferase/genética , Proteínas da Membrana Plasmática de Transporte de Dopamina/genética , Potenciais Evocados/genética , Retroalimentação Psicológica/fisiologia , Polimorfismo Genético/genética , Assunção de Riscos , Proteínas da Membrana Plasmática de Transporte de Serotonina/genética , Adolescente , Análise de Variância , Mapeamento Encefálico , Comportamento de Escolha/fisiologia , Eletroencefalografia , Feminino , Jogos Experimentais , Humanos , Tempo de Reação/genética , Adulto JovemRESUMO
OBJECTIVE: Feedback-related negativity (FRN) is associated with reinforcement learning and punishment sensitivity. Furthermore, reinforcement learning proficiency can be predicted from pre-task baseline EEG theta/beta ratio. In this study it was examined whether there was a relation between baseline theta/beta ratio in rest and FRN amplitude during a gambling task, and if such a correlation would be related to theta activity or to beta activity. METHODS: Baseline EEG and a self-report measure of punishment sensitivity (BIS) were obtained from 52 healthy volunteers. FRN was recorded during a gambling task. RESULTS: FRN amplitude was negatively correlated with theta/beta ratio in high BIS individuals. Furthermore, source localization indicated that baseline theta activity generated in the anterior cingulate cortex (ACC) accounted for this correlation. For low BIS individuals no correlation was found. CONCLUSIONS: An association between high baseline theta/beta ratio with low amplitude FRN and high risk-taking can be found in individuals who score sufficiently high on the BIS scale. This relationship is carried mostly by baseline theta activity, but not by beta activity. SIGNIFICANCE: This link between baseline brain activity, self-report measures and feedback processing may contribute to further understanding the biological basis of conditions that are accompanied by abnormal theta/beta ratio and reward processing, such as attention deficit hyper activity disorder (ADHD).
