Impact of Subclinical Behavioral Problems on Limbic System Development MRI Insight

Abstract

The limbic system (LS) regulates emotions, memory, and behavior. Dysfunction in LS regions such as the hippocampus, amygdala, and prefrontal cortex has been associated with mental health and behavioral disorders that often begin during childhood and adolescence. Previous studies indicate that parental internalizing problems (e.g. anxiety, depression) and externalizing problems (e.g. substance abuse, aggression) can negatively impact a child's mental health, behavior regulation and brain development. While prior research has largely focused on clinical populations, this dissertation examines whether subtle variation in parental and child behavior problems relates to LS volumes in typically developing children and adolescents. This study uses data from the general population in the United States collected by Adolescent Brain Cognitive Development (ABCD) Study Group. The dissertation had two main aims: (1) assess relationship between subclinical parental behavior problems and children's LS brain structure volumes using structural MRI, and (2) investigate associations between normative child behavior problems and LS structures using structural and diffusion MRI. The findings reveal distinct patterns of LS development in children and adolescents based on parental internalizing and externalizing behaviors. Gender-specific differences in these patterns also emerged, suggesting potential variations in risk profiles for later onset mental disorders. This highlights the importance of considering parental mental health when addressing behavior problems in children and adolescents. Additionally, the identified associations between child behavior problems and limbic structures underscore the potential for early intervention to prevent clinical symptoms onset and atypical brain development. Strong associations were also found between externalizing (and internalizing) problems and reduced LS white matter volumes, emphasizing the need for targeted support in emotionally distressed young males. Notably, the dissertation employs novel quantile (median) regression analysis methods to examine the entire distribution of LS brain regions to provide insights in risk and resilience trajectories for mental disorders and behavior dysregulation. Overall, the dissertation supports the hypothesis that subclinical behavior problems in children and adolescents relate to atypical LS development. This supports the value of early mental health screening and initiate intervention for at-risk individuals.