Early adversity, lasting impact: Characterizing cortical morphology in youth with prenatal alcohol exposure.
BACKGROUND Prenatal alcohol exposure (PAE) occurs in ~10% of pregnancies in North America and can alter brain development. Prior research on brain morphology in children with PAE shows mixed findings for cortical thickness, and only a few studies have investigated more complex morphological features, showing decreased gyrification with PAE. Here, we use four anatomical measures to provide a comprehensive characterization of cortical morphology in youth with PAE compared to unexposed youth. METHODS T1-weighted Magnetic Resonance Imaging (MRI) was used to examine cortical morphology metrics in 163 scans from 121 youth (56 with PAE) aged 7-21 years. Each participant had between 1 and 3 scans. Images were processed to segment 98 cortical brain regions. Linear mixed-effects models were used to test the effects of PAE on cortical gyrification index, thickness, sulcal depth, and shape complexity index, as well as their relationships with age. RESULTS Individuals with PAE had significantly lower gyrification (β=-0.17, q = 0.028) and sulcal depth (β=-0.60, q = 0.013) in the right pars triangularis, lower shape complexity in the right occipital pole (β=-0.019, q = 0.012), and higher shape complexity in the right medial orbital gyrus (β=0.017, q = 0.012), compared to unexposed youth. PAE moderated the relationship between age and both gyrification and sulcal depth in several regions such that sulcal depth and gyrification decreased with age in the PAE group but slightly increased with age (or remained stable) in the unexposed group. CONCLUSION These findings build upon previous reports of structural and developmental differences in youth with PAE, suggesting that gyrification may be more sensitive to the effects of PAE than cortical thickness.