In Vivo Fetal Magnetic Resonance Imaging Reveals Gestational Sexual Dimorphism in Rhesus Macaque Neurodevelopment

Motivation: Current noninvasive fetal imaging investigations in rhesus macaque neurodevelopment are typically insufficiently powered to consider the impact of sex. Goal(s): Our goal was to determine if in vivo MRI could detect differences in cortical development between male and female rhesus macaque fetuses. Approach: 109 T2-weighted acquisitions of male and female rhesus macaque fetuses spanning mid- to late gestation were anatomically parcellated yielding volume and surface measures. Results: A sex-by-age interaction (males increasingly larger with advancing gestational age) was found for cortical plate volume and surface area, but no difference was observed for cortical curvature or thickness. Impact: Our investigation provides the first evidence of significant sexual dimorphism in fetal rhesus macaque morphological neurodevelopment, highlighting the importance of fetal sex in comparisons of normative development and disease, and supplying additional evidence for radial neural migration's role in folding.