Epigenetic modification of the oxytocin receptor gene is associated with emotion processing in the infant brain.

• First developmental neuroimaging epigenetics study with human infants. • Oxytocin receptor gene methylation (OXTR m) assessed in a large sample of infants. • OXTR m predicts inferior frontal brain responses to emotional faces using fNIRS. • Higher OXTR m linked to enhanced brain responses to angry and fearful faces. • OXTR m contributes to variability in social brain function early in ontogeny. The neural capacity to discriminate between emotions emerges early in development, though little is known about specific factors that contribute to variability in this vital skill during infancy. In adults, DNA methylation of the oxytocin receptor gene (OXTR m) is an epigenetic modification that is variable, predictive of gene expression, and has been linked to autism spectrum disorder and the neural response to social cues. It is unknown whether OXTR m is variable in infants, and whether it is predictive of early social function. Implementing a developmental neuroimaging epigenetics approach in a large sample of infants (N = 98), we examined whether OXTR m is associated with neural responses to emotional expressions. OXTR m was assessed at 5 months of age. At 7 months of age, infants viewed happy, angry, and fearful faces while functional near-infrared spectroscopy was recorded. We observed that OXTR m shows considerable variability among infants. Critically, infants with higher OXTR m show enhanced responses to anger and fear and attenuated responses to happiness in right inferior frontal cortex, a region implicated in emotion processing through action-perception coupling. Findings support models emphasizing oxytocin's role in modulating neural response to emotion and identify OXTR m as an epigenetic mark contributing to early brain function. [ABSTRACT FROM AUTHOR]