Amygdala-hippocampus connectivity and childhood depressive symptoms: subnuclei insights and self-concept roles

Amygdala-hippocampal connectivity is a promising area of study for an understanding of the neurobiological mechanisms of depression. In this study, we examined the association between amygdala-hippocampal connectivity and depressive symptoms in children with a specific focus on the subnuclei level. We then examined whether self-concept mediated brain-behavior associations. Resting-state functional magnetic resonance imaging (fMRI) was performed at age 7.5 years (N = 319), followed by self-reported depressive symptoms and self-concept between ages 8.5 and 10.5 years, using the Children's Depression Inventory (CDI-2) and Piers-Harris Children's Self-Concept Scale (PHCSC) respectively. We conducted multiple regression analyses to examine the associations between the amygdala-hippocampus resting-state functional connectivity (RSFC) and CDI scores, first at the whole-region level and subsequently at the subnuclear level. Mediation analyses were then performed to explore the mediating role of self-concept in these brain-behavior associations. We observed a significant association between left amygdala-anterior hippocampus connectivity and CDI total scores, primarily driven by the left superficial amygdala. Further exploration at sub-symptomatic levels highlighted an association with negative cognition. Finally, self-concept mediated the association between left amygdala-anterior hippocampus connectivity and depressive symptoms in children. This study provided valuable insights into the associations among amygdala-hippocampal subnuclei connectivity, childhood depressive symptoms, and self-concept. Diminished left superficial amygdala-anterior hippocampus connectivity may serve as an early biomarker to identify depressive symptoms, particularly in children with negative cognition problems.