Involved in Gene - Environment Contributions to the Development of Infant Vagal Reactivity: The Interaction of Dopamine and Maternal Sensitivity.
• She studied the dopamine receptor genes DRD2 and DRD4 and maternal sensitivity as predictors of infant respiratory sinus arrhythmia (RSA) and RSA changes as a reaction to stressors. Findings indicate that having a high resting RSA (vagal tone) is implicated with having a good temperament, good attention, sociability, and a healthy response to stimuli in infancy, while a decrease in the ability to suppress RSA and withdraw the vagal brake (variability in heart rate when one breathes -- increasing HR during inhalation) during periods of stress. Mutations of dopaminergic receptors, DRD2 and DRD4 are associated with impulsivity and low inhibition and aggression. The findings of this study indicate a three way interaction between genes, environment, and age, in that by 12 months, genes (the mutations or lack of mutations of the Dopaminergic Receptors a child has), the environment (low or high maternal care) and the age (12 month, vs. 6 months when maternal care has not had enough time to impact the RSA suppression system) all impact the regulation of heart rate and the RSA change in periods of stress.