Amygdala and Prefrontal Cortex Maturational Differences in Children and Adolescents With Prenatal Alcohol Exposure

Abstract

Background: Prenatal alcohol exposure (PAE) has widespread effects on brain development. Alterations to the maturational timing of the amygdala, prefrontal cortex (PFC), and the white matter tracts connecting them may underlie behavioral differences, such as elevated risk taking and impulsivity in youth with PAE.

Methods: Here, we used T1 and diffusion-weighted magnetic resonance imaging to evaluate amygdala and PFC macrostructure (volume) and uncinate fasciculus and amygdala-PFC white matter tract microstructure (fractional anisotropy, mean diffusivity) development longitudinally in children and adolescents with PAE (n = 92 individuals [165 scans], ages 2-18 years) and unexposed participants (n = 148 individuals [606 scans], ages 2-17 years). We used generalized additive mixed-effects models to examine age-related changes in volume, fractional anisotropy, and mean diffusivity.

Results: Children and adolescents with PAE showed no significant amygdala volume development across the age range, and, compared with their unexposed counterparts, had shorter and delayed PFC development, earlier uncinate fasciculus development, and more protracted amygdala-PFC tract development in our age range. Participants with PAE also had smaller amygdala and PFC volumes, higher fractional anisotropy, and lower mean diffusivity in both tracts than unexposed individuals.

Conclusions: Our findings show altered maturational patterns in amygdala-PFC structures and circuitry among children and adolescents with PAE that suggest reduced brain plasticity. Differences in the developmental timing of these regions may underlie behavioral challenges, such as elevated risk taking and impulsivity, in those with PAE.

Keywords: Amygdala; Magnetic resonance imaging; Neurodevelopment; Prefrontal cortex; Prenatal alcohol exposure; White matter tract.