Exposure to Community Violence as a Mechanism Linking Neighborhood Disadvantage to Amygdala Reactivity and the Protective Role of Parental Nurturance

• In Event: - Adversity in Context: Associations Between Family and Neighborhood Disadvantage, Parenting, and Child Outcomes

Abstract

Children in disadvantaged neighborhoods are exposed to multiple stressors, including violent crime. Alarmingly, 68% of U.S. children reported exposure to at least one form of violence within a year (Finkelhor et al., 2015), and youth in disadvantaged neighborhoods experience double the exposure (Stein et al., 2003), putting them at great risk for maladaptive outcomes (Fowler et al., 2009). Extant data suggest that neighborhood disadvantage may influence development via the impact of stress on the structure and function of the amygdala, a region involved in socioemotional functioning, threat processing, and fear learning (Hyde et al., 2020). Although behavioral research suggests that exposure to community violence is a consistent mechanism linking neighborhood disadvantage to maladaptive behavioral outcomes, no research has examined exposure to community violence as a mechanism linking neighborhood disadvantage to altered amygdala reactivity, a primary aim of the current study. Lastly, though neighborhood disadvantage predicts maladaptive outcomes, many youth facing adversity exhibit resilience, and nurturing parenting may play a critical role in these good outcomes (Luthar, 2006). Our second aim was to examine whether nurturing parenting could buffer youth from the impacts of disadvantage and exposure to community violence.

Twins 7-19 years (N=354 families, 708 twins) were recruited from birth records from neighborhoods with above average levels of disadvantage. Twins completed the KID-Screen for Adolescent Violence Exposure to report their exposure to community violence (Flowers et al., 2000) and the Parental Environment Questionnaire (PEQ; Elkins et al., 1997) to report perceptions of their parent’s nurturance. Participants also completed an implicit socioemotional face processing task (Hariri et al., 2002) using fMRI, in which they matched face identities (4 blocks of fear, anger, neutral happy) or geometric shapes (5 blocks).

We extracted amygdala activation for each participant from the main effects of the contrast fearful + angry faces > shapes using an anatomical region of interest. We ran multi-level mediation and moderated mediation structural equation models (SEM) in Mplus. All models controlled for twin age, gender, and race/ethnicity.

We found evidence for the hypothesized indirect effect; twins living in more disadvantaged neighborhoods were more exposed to community violence, which in turn, was associated with greater right amygdala reactivity to threat (Figure 1). Moreover, parental nurturance moderated this pathway, in two ways. First, neighborhood disadvantage was only associated with exposure to community violence at low and mean, but not high parental nurturance (Figure 2). Second, exposure to community violence was only associated with greater amygdala reactivity at low parental nurturance, but not mean or high levels. Finally, the indirect pathway linking neighborhood disadvantage to amygdala reactivity was conditional on parental nurturance as indicated by a significant indirect effect at low, but not high or mean parental nurturance.

One way neighborhood disadvantage impacts youth brain function is by increasing exposure to community violence. However, nurturing parenting diminished these effects. Despite exposure to high neighborhood disadvantage, youth with highly nurturing parents were not more exposed to community violence, and for those who were exposed, nurturing parenting buffered the impact of violence exposure on the brain.

Authors

• Gabriela Lydia Suarez, University of Michigan - Ann Arbor
  Presenting Author

• S. Alexandra Burt, Michigan State University

• Arianna Gard, University of Maryland - College Park

• Kelly Klump, Michigan State University

• Luke W. Hyde, University of Michigan - Ann Arbor