Socioeconomic Status and Subdivisions of the Amygdala and Hippocampus in Children and Adolescents

Socioeconomic status (SES) in childhood can impact behavioral and brain development. Past work has consistently focused on the amygdala and hippocampus, two brain areas critical for emotion, memory, and learning. While there are SES differences in total amygdala and hippocampal volumes, there are many unanswered questions in this domain connected to neurobiological specificity and whether these effects vary by participant age or sex. To address these gaps, we combined multiple large neuroimaging datasets of children and adolescents with information about neurobiology and SES (N=2,765). We examined subdivisions of the amygdala and hippocampus, derived from Freesurfer, using linear mixed effects models. Higher SES was associated with larger volumes across all three amygdala subdivisions examined, the superficial cortical division, basolateral complex, and centromedial region. Within the hippocampus, SES was specifically related to volumes in the head, with no significant associations for the body or tail. Contrary to our hypotheses, we found no significant interactions between SES and participant age or sex after correcting for multiple comparisons, suggesting these associations were relatively consistent across the developmental period examined (ages 5-18) and similar for males and females. These results fill in important gaps regarding the neurobiological specificity of SES effects, demonstrating associations across functionally distinct subdivisions of these critical brain structures.