Primary cortical folding in the human newborn: An early marker of later functional development

In the human brain, the morphology of cortical gyri and sulci is complex and variable among individuals, and it may reflect pathological functioning with specific abnormalities observed in certain developmental and neuro-psychiatric disorders. Since cortical folding occurs early during brain development, these structural abnormal-ities might be present long before the appearance of functional symptoms. So far, the precise mechanisms responsible for such alteration in the convolution pattern during intra-uterine or post-natal development are still poorly understood.Here we compared anatomical and functional brain development in vivo among 45 pre-mature newborns who experienced different intra-uterine environments: 22 normal singletons, 12 twins and 11 newborns with intrauterine growth restriction (IUGR).Using magnetic resonance imaging (MRI) and dedicated post-processing tools, we investigated early disturbances in cortical formation at birth, over the developmental period critical for the emergence of convolutions (26^36 weeks of gestational age), and defined early ‘endophe-notypes ’ of sulcal development.We demonstrated that twins have a delayed but harmonious maturation, wit