Gene–Environment Contributions to the Development of Infant Vagal Reactivity: The Interaction of Dopamine and Maternal Sensitivity


  • This study was supported by The North Carolina Child Development Research Collaborative which is funded by the National Science Foundation through a Children’s Research Initiative Grant #BCS-0126475. The authors would like to thank all the parents who participated in the Durham Child Health and Development Study and the research assistants for their valuable help in collecting this data. Also, the authors would like to thank Trudy F. C. Mackay and her laboratory at North Carolina State University for their contributions in genotyping for this project. Finally, we are grateful for the assistance and encouragement of the late Gilbert Gottlieb.

concerning this article should be addressed to Cathi Propper, Center for Developmental Science, University of North Carolina at Chapel Hill, 100 East Franklin Street, CB# 8115, Chapel Hill, NC 27599-8115. Electronic mail may be sent to


This study investigated dopamine receptor genes (DRD2 and DRD4) and maternal sensitivity as predictors of infant respiratory sinus arrhythmia (RSA) and RSA reactivity, purported indices of vagal tone and vagal regulation, in a challenge task at 3, 6, and 12 months in 173 infant–mother dyads. Hierarchical linear modeling (HLM) revealed that at 3 and 6 months, RSA withdrawal in response to maternal separation was greater (suggesting expected physiological regulation) in infants without the DRD2 risk allele than those with the risk allele. At 12 months, infants with the risk allele who were also exposed to maternal sensitivity showed levels of RSA withdrawal comparable to infants who were not at genetic risk. Findings demonstrate the importance of developmental analysis of gene–environment interaction.