Insights from non-human animal models to developmental human behavioral epigenetics

Human neurodevelopment is a dynamic and protracted process. It starts in the pre-natal life, driven by genetic information, and continues unfolding following region-specific pathways up to early adulthood (Gogtay et al., 2004; Koenderink & Uylings, 1995; Petanjek et al., 2011). Especially during the pre-natal and early post-natal life, the developing brain depends on and is sensitive to external inputs that shape its architecture and fine-tune neural connectivity patterns according to environmental requirements (Branchi & Cirulli, 2014; Fox, Levitt, & Nelson, 2010; Hensch, 2005; Takesian & Hensch, 2013; Teicher, Samson, Anderson, & Ohashi, 2016). Environmental inputs are therefore critical for a normative development. On the other hand, adverse conditions occurring during sensitive periods for the nervous system maturation can interact with genetic make-up and bias developmental trajectories toward maladaptive outcomes, as demonstrated by increased occurrence of psychopathology and psychiatric conditions following childhood neglect, maltreatment and abuse (Benjet, Borges, & Medina-Mora, 2010; Bick & Nelson, 2016; Cohen, Brown, & Smaile, 2001; Green et al., 2010; Kessler et al., 2010; Widom, 1999).