Neural and Behavioral Correlates of Childhood Social Exposures

Abstract

Childhood behavior problems substantially impact individuals, families, and communities. Poverty and social disadvantage are known risk factors for child behavior problems, while healthy social environments may buffer effects of social disadvantage. Yet, neural mechanisms underlying these relationships remain understudied. This dissertation presents three studies about neural and behavioral correlates of childhood social exposures using data from the Generation R Study, a birth cohort in Rotterdam, the Netherlands. The first study (n = 2,653) investigates the association between one facet of a healthy childhood social environment—healthy family functioning—and brain white matter microstructure in preadolescence. The study finds evidence that healthier levels of maternal-report prenatal family functioning, but not family functioning in mid-childhood, are associated with lower mean diffusivity across the brain, a marker of more favorable white matter microstructure. The second study (n = 2,905) assesses two closely related types of childhood physically threatening experiences—actual violence exposure and mere threatened violence exposure alone—and their association with both preadolescent global brain structure and the structure of specific corticolimbic regions of the brain involved in threat response. Results suggest actual violence exposure—but not mere threatened violence exposure alone—is associated with smaller global cortical gray matter, subcortical gray matter, and white matter volume, even after extensive adjustment for possible confounders. We also find that actual violence exposure is associated with smaller amygdala volume. The final study (n = 3,154) investigates mediation and moderation of the association between violence exposure and behavior problems. We find that childhood violence exposure is associated with higher total preadolescent behavior problems and lower amygdala volume on average. We also find that healthy family functioning—but not high parental socioeconomic status or sex—may substantially alter both of these associations. For example, violence exposure among children of lower functioning families is associated with more preadolescent behavior problems than among children of higher functioning families. However, we find no evidence that amygdala volume partially mediates the association between violence exposure and behavior problems. Together, these studies contribute to research investigating brain-based mechanisms linking childhood risk and protective factors to the development of childhood behavior problems.