Structural variations in prefrontal cortex mediate the relationship between early childhood stress and spatial working memory

Abstract

A large corpus of research indicates that exposure to stress impairs cognitive abilities, specifically executive functioning dependent on the prefrontalcortex(PFC).WecollectedstructuralMRIscans(nβ61),well-validatedassessmentsofexecutivefunctioning,anddetailedinterviews assessing stress exposure in humans to examine whether cumulative life stress affected brain morphometry and one type of executive functioning, spatial working memory, during adolescence-a critical time of brain development and reorganization. Analysis of variations in brain structure revealed that cumulative life stressandspatialworkingmemorywererelated to smallervolumesin thePFC,specifically prefrontal gray and white matter between the anterior cingulate and the frontal poles. Mediation analyses revealed that individual differences in prefrontal volumesaccounted for the association between cumulative life stressandspatial workingmemory.These results suggest that structural changes in the PFC may serve as a mediating mechanism through which greater cumulative life stress engenders decrements in cognitive functioning. © 2012 the authors.