From the abstract:
Using high-resolution structural MRI, we measured subcortical gray and white matter brain volumes in a cohort (N = 143) of 1-month infants and examined characteristics of these volumetric measures throughout this early period of neurodevelopment. We show that brain volumes undergo age-related changes during the first month of life, with the corresponding patterns of regional asymmetry and sexual dimorphism. Specifically, males have larger total brain volume and volumes differ by sex in regionally specific brain regions, after correcting for total brain volume. Consistent with findings from studies of later childhood and adolescence, subcortical regions appear more rightward asymmetric. Neither sex differences nor regional asymmetries changed with gestation-corrected age. Our results complement a growing body of work investigating the earliest neurobiological changes associated with development and suggest that asymmetry and sexual dimorphism are present at birth.