Functional Polymorphism of the Mu-Opioid Receptor Gene (OPRM1) Influences Reinforcement Learning in Humans
2011

How a Gene Affects Learning from Rewards

Sample size: 63 publication 10 minutes Evidence: moderate

Author Information

Author(s): Lee Mary R., Gallen Courtney L., Zhang Xiaochu, Hodgkinson Colin A., Goldman David, Stein Elliot A., Barr Christina S.

Primary Institution: National Institute on Drug Abuse, Intramural Research Program

Hypothesis

Does the OPRM1 A118G polymorphism influence reinforcement learning in humans?

Conclusion

The study found that individuals with the OPRM1 G allele showed a decline in response to rewards over time, unlike AA homozygotes who increased their response bias.

Supporting Evidence

  • AA homozygotes increased their response bias over time, while G allele carriers showed a decline.
  • The study suggests a mechanism by which the OPRM1 polymorphism may reduce response to natural rewards.
  • Previous studies have linked reduced reward responsiveness to various psychological conditions.

Takeaway

Some people have a gene that makes them less responsive to rewards, which means they might not learn from positive experiences as well as others.

Methodology

Participants completed a probabilistic signal detection task to assess the impact of the OPRM1 polymorphism on reward learning.

Potential Biases

Potential confounding factors related to drug use and ethnicity were considered but may still influence results.

Limitations

The sample size was small and the study was conducted in a controlled laboratory setting, which may not reflect real-world behavior.

Participant Demographics

Participants included 51 AA homozygotes and 12 G allele carriers, with a mean age of approximately 32 years.

Statistical Information

P-Value

p=0.005

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0024203

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