Adaptive Regulations in Developing Rodents Following Neonatal Challenges

Abstract

Developmental phenotypic plasticity is a mechanism by which events early in life program brain for a pattern of neuroendocrine and behavioral responses in later life. The goal of this chapter is to give the reader a better understanding of what is developmental phenotypic plasticity and how it can lead to adaptive phenotypes in adulthood. Experimental evidences from rodents show that early experiences influence long-term development of behavioral, neuroendocrine, and cognitive functions. Different factors have been suggested to mediate the effects of neonatal conditions on offspring development, but their exact contribution as well as their interaction still needs to be clarified. Several studies demonstrated the important role of maternal behavior in mediating the effects of neonatal challenges on adaptive regulations in the developing rodents. It has been suggested that there is an inverse relationship between the amount of active maternal care received by the offspring and their later reactivity to stressful or challenging events. However, other studies found a dissociation between the level of maternal care and offspring phenotype. These results suggest that aside from the level of maternal care, non-maternal factor (gender, neonatal glucocorticoid levels) contributes to the adjustment of offspring phenotype to early environmental cues. Altogether, rodents-based evidence suggests that developmental plasticity is a very complex phenomenon mediated by multiple factors that interact one to each other. Ultimately, these researches will help to better understand how the conditions from the neonatal environment affect brain development and can lead to adaptive phenotypes in adulthood.