Title

Individual Differences in the Dopaminergic Reward System: The Effect of Genetic Risk on Neural Reward Sensitivity and Risky Choice

Graduation Year

2015

Document Type

Thesis

Degree

M.A.

Degree Name

Master of Arts (M.A.)

Department

Psychology

Degree Granting Department

Psychology

Major Professor

Geoffrey F. Potts, Ph.D.

Committee Member

Marina A. Bornovalova, Ph.D.

Committee Member

Toru Shimizu, Ph.D.

Keywords

dopamine, impulsivity, medial-frontal negativity, reward sensitivity, risk-taking behavior

Abstract

When making decisions, individuals evaluate several possible outcomes of their choice; however, some display heightened reward sensitivity, despite the potential for future negative consequences, which can lead one to make risky choices. Rewards are processed in the mesolimbic dopamine reward system, and this system is in part modulated by genetic polymorphisms that are associated with dopamine transmission. The current study tested if genetic polymorphisms that are associated with enhanced dopamine neurotransmission will be more neurally reward sensitive, score higher on self-reported impulsivity, and make riskier choices. In a sample of 85 participants, five genetic polymorphisms were genotyped and used to create a genetic risk score that represented dopamine transmission efficiency. Two groups (high and low efficiency) were created via median split and then compared on neural reward sensitivity (assessed by event-related potentials, specifically, the medial-frontal negativity [MFN] and the error-related negativity), impulsivity (assessed via self-report), and risky choice (measured using the Balloon Analogue Risk Task and self-report measures). Results indicated that individuals with higher levels of dopamine displayed a less negative MFN and more drinking behaviors than those with lower levels of dopamine. These results suggest that individuals with higher levels of dopamine are less sensitive to punishments, which could lead them to make riskier choices.

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