Childhood abuse and reduced cortical thickness in brain regions involved in emotional processing

Abstract

Background: Alterations in gray matter development represent a potential pathway through which childhood abuse is associated with psychopathology. Several prior studies find reduced volume and thickness of prefrontal (PFC) and temporal cortex regions in abused compared with nonabused adolescents, although most prior research is based on adults and volume-based measures. This study tests the hypothesis that child abuse, independent of parental education, predicts reduced cortical thickness in prefrontal and temporal cortices as well as reduced gray mater volume (GMV) in subcortical regions during adolescence.

Methods: Structural MRI scans were obtained from 21 adolescents exposed to physical and/or sexual abuse and 37 nonabused adolescents (ages 13-20). Abuse was operationalized using dichotomous and continuous measures. We examined associations between abuse and brain structure in several a priori-defined regions, controlling for parental education, age, sex, race, and total brain volume for subcortical GMV. Significance was evaluated at p < .05 with a false discovery rate correction.

Results: Child abuse exposure and severity were associated with reduced thickness in ventromedial prefrontal cortex (PFC), right lateral orbitofrontal cortex, right inferior frontal gyrus, bilateral parahippocampal gyrus (PHG), left temporal pole, and bilateral inferior, right middle, and right superior temporal gyri. Neither abuse measure predicted cortical surface area or subcortical GMV. Bilateral PHG thickness was inversely related to externalizing symptoms.

Conclusions: Child abuse, an experience characterized by a high degree of threat, is associated with reduced cortical thickness in ventromedial and ventrolateral PFC and medial and lateral temporal cortex in adolescence. Reduced PHG thickness may be a mediator linking abuse with externalizing psychopathology, although prospective research is needed to evaluate this possibility.

Keywords: Abuse; childhood adversity; cortical thickness; temporal cortex; ventromedial prefrontal cortex.

Conflict of interest statement

No conflicts declared.

Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Figures

Figure 1

Cortical thickness ROIs showing associations with child abuse severity. Abuse severity was significantly associated with cortical thickness in prefrontal cortex and temporal cortex ROIs, after adjusting for parental education, race, sex, and age. The vmPFC, left temporal pole, and right and left PHG are shown on the medial surface of an inflated brain, and the right lateral OFC, right IFG, right and left ITG, right STG, and right MTG are shown on the lateral surface. Scatterplots of abuse severity and ROI thickness are presented. Abbreviations: IFG, inferior frontal gyrus; inferior temporal gyrus, ITG; L, left; lOFC, lateral orbitofrontal cortex; middle temporal gyrus, MTG; PHG, parahippocampal gyrus; R, right; ROI, region-of-interest; superior temporal gyrus, STG; TP, temporal pole; vmPFC, ventromedial prefrontal cortex.

Figure 2

Cortical thickness ROIs showing associations with externalizing psychopathology. Inverse relationships between cortical thickness in the left and right PHG and externalizing symptoms are plotted. Externalizing symptoms were inversely associated with cortical thickness in the left and right PHG, which are shown on the medial surface of an inflated brain. Scatterplots of externalizing psychopathology and ROI thickness are presented. Abbreviations: PHG, parahippocampal gyrus; ROI, region-of-interest.