An epigenetic framework for understanding contextual influences on neural and socio-emotional development: Narrative review and case-study of the oxytocin receptor.

Inter-individual differences in the way one processes and responds to socio-emotional situations are influenced by a collection of developmental, environmental and neurobiological factors. An epigenetic framework is uniquely poised to investigate how individual contextual histories contribute to and affect biological mechanisms, including brain development, which are at the root of human socio-emotional development. This review aims to inform developmental scientists of fundamental features and considerations in DNA methylation research. We select a well-characterized candidate neuromodulator for socio-emotional processes - DNA methylation of the oxytocin receptor (OXTRm) - as a case study example. We first highlight what makes this marker well-characterized and a strong candidate for human neuroimaging and developmental studies. This includes thorough tissue validation and functional regulation of gene transcription in animal models and humans for specific regions in OXTR. We then review evidence for environmental influence on OXTRm levels and associations with psychosocial functioning. Next we summarize the findings of OXTRm in relation to neural function and anatomy across the lifespan, and discuss the potential of this approach to make significant advancements in our understanding of how experience can affect neurodevelopmental trajectories with the use of longitudinal studies. Finally, we outline additional methodological considerations for researchers including other biological and social factors, current measurement limitations, and recommendations for future developmental neuroimaging epigenetic studies beyond the scope of the oxytocinergic system.