Epigenetic and Neurodevelopmental Perspectives on Variation in Parenting Behavior

Abstract

Mother-infant interactions in rodents can be used to explore the biological basis of postnatal parental effects. There is emerging evidence from laboratory studies that variation in early life experiences can induce molecular changes in the developing brain which lead to activation or silencing of genes. These epigenetic effects may account for the stability of the effects of parenting on offspring development and the transmission of parenting from one generation to the next. In this article, we highlight evidence supporting a role for epigenetic mechanisms in the consequences, transmission, and variability in parenting. Although primarily drawn from laboratory studies in rodents, this evidence may also provide some insights into key questions within the study and practice of human parenting. We discuss these questions, highlighting both the challenges and benefits of using translational approaches.

Figure 1

Epigenetic regulation of gene expression. DNA is wrapped around histone proteins and gene expression is dependent on the enzyme RNA Polymerase II accessing the DNA and creating RNA. (A) Attachment of methyl chemical groups (M) to the DNA sequence suppresses gene expression. (B) Histone proteins have “tails” that can be modified by attachment of acetyl (Ac) and methyl groups to specific sites. Histone tail acetylation increases gene transcription, while histone tail methylation typically decreases gene activity. (C) Small RNA molecules such as microRNAs can bind to and degrade newly transcribed RNA, repressing gene activity.

Figure 2

Neurobiology of the rodent maternal brain. The neurobiological circuits involved in variation in maternal LG include the medial preoptic area (MPOA), bed nucleus of the stria terminalis (BNST), lateral septum (LS), central amygdala (Amyg), ventral tegmental area (VTA), and nucleus accumbens (NAc). Levels of oxytocin and estrogen receptors in the MPOA influence the frequency of maternal LG care displayed. These hypothalamic effects have downstream consequences for activation within the mesolimbic dopamine (DA) system, which includes projections from the VTA to NAc. Environmental experiences shape the development of these circuits leading to altered LG behavior.