Exposure to Community Violence is Associated with Heightened Amygdala Reactivity to Threat

• In Event: Poster Session 11
  In Poster Session: PS 11 Topic - Biological Processes: Neuroscience and Genetics

Abstract

Between 50-96% of youth residing in urban areas are exposed to community violence in their lifetime (Stein et al., 2003). Exposure to community violence (ECV) is associated with many negative consequences for youth, especially internalizing and externalizing behaviors (Fowler et al., 2009; Zinzow et al., 2009). ECV represents a salient form of threat exposure and is hypothesized to sculpt functional development of the amygdala due to its role in threat detection, aversive learning, and mobilization of defensive responses (LeDoux, 2003). Studies consistently report that children exposed to hostile conditions (e.g., physical, sexual, and emotional abuse, as well as exposure to domestic violence and other forms of violence) exhibit heightened amygdala reactivity to threat-related stimuli (McLaughlin et al., 2019); however, few studies have examined whether or not exposure to community violence is linked to altered amygdala reactivity. This current study evaluated the association between ECV and amygdala reactivity to threat (i.e., anger and fear faces) and ambiguity (neutral faces).

A sample of twins aged 7-19 years (N=354 families, 708 twins) were recruited from birth records to be representative of families with twins living in south-central Michigan with a high oversampling for exposure to neighborhood disadvantage. Twin self-report on the KID-Screen for Adolescent Violence Exposure was used to assess each twin’s exposure to witnessing interpersonal violence or hearing about violent events (Flowers et al., 2000). Participants also completed an implicit socioemotional face processing task (Hariri et al., 2002) using fMRI, in which they were asked to match face identities (4 blocks of fear, anger, neutral happy) or geometric shapes (5 blocks).

Multiple regression models in SPM12 were used to examine whether ECV was associated with amygdala reactivity to angry and fear faces > shapes and neutral faces > shapes, controlling for twin age and sex. Results revealed that greater twin-reported ECV was associated with greater right amygdala reactivity to angry and fear faces versus shapes (Table 1, Figure 1). Exploratory analyses revealed that these results were more strongly related to amygdala reactivity to fearful faces versus shapes than angry faces versus shapes (Table 1). Importantly, these findings remained significant after controlling for parent-reported annual income and maternal education.

The current study demonstrates that ECV is associated with increased amygdala reactivity to threat. Future analyses will utilize a monozygotic twin difference model, which leverages the fact that monozygotic twins have identical DNA and yet different exposures and outcomes. This model will test whether the associations between ECV and amygdala reactivity are environmental in origin and not due to gene-environment correlation.

Authors

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

• S. Alexandra Burt, Michigan State University
  Non-Presenting Author

• Arianna Gard, University of Maryland - College Park
  Non-Presenting Author

• Kelly Klump, Michigan State University
  Non-Presenting Author

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