Poster #8 - Association of Maltreatment Exposures with Amygdalar Nuclei and Hippocampal Subfield Volume in Adolescence

• In Event: Poster Session 12

Abstract

As central structures for threat processing, the amygdala and hippocampus have been main targets of research focusing on the neurodevelopmental mechanisms underlying effects of adversity exposure. Lower hippocampus and amygdala volume have been established as correlates of maltreatment and particularly threat exposure in adult and youth samples (McLaughlin et al., 2019; Paquola et al., 2016). Yet, there is still considerable heterogeneity in study results, especially in developmental samples. Methodological advancements allowing for an automatic assessment of amygdalar nuclei (Saygin et al., 2017) as well as hippocampal subfield volume (Iglesias et al., 2015) could aid in explaining these varying findings. Only particularly stress-sensitive subregions of the amygdala (i.e., basolateral complex) and hippocampus (i.e., CA3, CA4/DG, and CA1) might be affected by adversity exposure (Dahmen et al., 2018; Oshri et al., 2019). Studying specific, relative effects of maltreatment subtype exposure on hippocampal subfield and amygdalar nuclei volume in adolescence could further help illuminating previous divergent findings regarding total hippocampal and amygdala volume in developmental samples.
Therefore, we tested the effects of abuse, neglect, and emotional maltreatment on amygdalar nuclei and hippocampal subfield volume in a sample of 98 adolescents aged 12-17 (M=14.68, SD=1.95; 51% girls) comparing participants with maltreatment exposures (n=58) to a carefully matched control group (n=40). To this end, we obtained T1-weighted MRI scans from every participant, which were pre-processed and analyzed for subregion volume using FreeSurfer. We assessed maltreatment with the Maltreatment Classification System (Barnett et al., 1993), based on caregiver interviews and child protection services records (if available). Information on chronicity, severity and number of different neglect, abuse or emotional maltreatment subtypes were included in the respective maltreatment subtype dimension as well as in an overall maltreatment score. First, we assessed categorical effects of maltreatment exposure on amygdalar nuclei (i.e., basolateral and centrocorticomedial complex) as well as hippocampal subfield volume (i.e., subiculum, CA1, CA3, CA4/DG) across the full sample. Second, we tested dimensional effects of overall maltreatment as well as maltreatment subtype exposure within maltreatment-exposed participants. All analyses were corrected for multiple comparisons.
Nonmaltreated and maltreated adolescents did not significantly differ in respect to amygdalar nuclei and hippocampal subfield volume. However, dimensional within-group analyses revealed a negative relationship between the extent of overall maltreatment exposure and the amygdalar basolateral complex volume (β=-.38, p=.004; see Figure 1), which survived controlling for intracranial volume, age, gender, and socioeconomic status (β=-.27, p=.013). No maltreatment subtype dimension displayed a significant association with hippocampal subfield or amygdalar nuclei volume over and above differences in all covariates.
This study is first to examine the effects of maltreatment subtype exposure on amygdalar and hippocampal subregions in a well-characterized sample of maltreated and nonmaltreated adolescents. We did not find evidence for specific, relative effects of abuse, neglect or emotional maltreatment. Nevertheless, our study adds to the existing literature by showing that adolescents’ level of overall maltreatment exposure relates to lower volume in the amygdalar basolateral complex, which has been shown to be particularly susceptible to stress due to its high glucocorticoid receptor density (Johnson et al., 2005).

Authors

• Charlotte Catharina Schulz, Leipzig University
  Presenting Author

• Lara Puhlmann, Max Planck Institute for Human Cognitive and Brain Sciences

• Lisa Folkens, Leipzig University

• Pascal Vrtička, University of Essex

• Lars Otto White, Leipzig University