Differential association of early experiences of threat and deprivation with cortical thickness.

• In Event: 1-151 - Beyond stress: Identifying specific pathways linking childhood adversity and mental health

Integrative Statement

Increasing evidence indicates that exposure to adverse experiences in early life can alter neural development. For example, exposure to maltreatment has been associated with reduced volume in brain regions involved in salience processing (eg. orbitofrontal cortex; Gold et al. 2016, Hanson et al. 2010) and lack of early life cognitive stimulation has been associated with thinner cortex in fronto-parietal control networks (Rosen et al. 2018). These neural differences may be an important mechanism through which early adversity increases risk for mental health and academic problems. However, prior research has been limited by a focus on single types of adversity. Because adversities often co-occur, assessing multiple dimensions of adverse environments to determine whether they have unique effects on brain structure and function is critical for identifying mechanisms linking these experiences with developmental outcomes.
Recent conceptual models posit that threat and deprivation are two dimensions of adverse environmental experiences that may have different neurodevelopmental consequences (Sheridan & McLaughlin, 2014). We examined the associations of these dimensions with cortical thickness in a sample of 149 youth aged 8-17 (M=12.75). Half of the sample was recruited based on exposure to experiences involving threat (i.e., violence) along with age- and sex-matched controls. Building on existing theory and prior evidence, we predicted that exposure to threat would be uniquely associated with thinner cortex in areas of the brain associated with salience processing including orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), insula, and medial temporal cortex, and that deprivation would be uniquely associated with thinner cortex in frontoparietal areas associated with cognitive control. We assessed multiple indicators of threat (physical and sexual abuse, domestic violence, community violence) and deprivation (emotional and physical neglect, low cognitive stimulation). Structural MRI scans were collected and cortical thickness was estimated using Freesurfer.
As predicted, youth exposed to threatening experience showed reduced thickness in a network of brain regions involved in salience processing, including bilateral insula, medial temporal cortex, right lateral OFC, and left dorsal and ventral ACC (Figure 2). Reduced thickness in left superior frontal cortex was also observed, although it did not persist after adjusting for co-occurring deprivation. In contrast, children exposed to deprivation exhibited reduced thickness in the predicted frontoparietal network (Figure 3). This association did not persist after controlling for co-occurring threat exposure, possibly due to the limited number of participants who experienced deprivation but not threat in our sample.
These findings provide support for a model in which different dimensions of adverse experiences in childhood are associated with distinct neurodevelopmental consequences. Threatening experiences in childhood may produce alterations in brain networks involved in salience processing, whereas experiences characterized by deprivation may have stronger effects on frontoparietal control networks involved in executive functioning. Understanding the impact of distinguishable types of exposure on brain structure may be crucial to understanding neurodevelopmental mechanisms linking early adversity with poor developmental outcomes.

Authors

• Matt Peverill, University of Washington
  Presenting Author

• Maya Rosen, University of Washington
  Non-Presenting Author

• Kelly Sambrook, University of Washington
  Non-Presenting Author

• Margaret Sheridan, University of North Carolina at Chapel Hill
  Non-Presenting Author

• Katie McLaughlin, Harvard University
  Non-Presenting Author