Cortical scaling of the neonatal brain in typical and altered development

Abstract

Theoretically derived scaling laws capture the non-linear relationships between rapidly expanding brain volume and cortical gyrification across mammalian species and in adult humans. However, the preservation of these laws has not been comprehensively assessed in typical or pathological brain development. Here we assessed the scaling laws governing cortical thickness, surface area and cortical folding in the neonatal brain. We also assessed multivariate morphological terms that capture brain size, shape and folding processes. The sample consisted of 375 typically developing infants, 73 preterm infants and 107 infants with congenital heart disease (CHD) who underwent brain magnetic resonance imaging (MRI). Our results show that typically developing neonates and those with CHD follow the cortical folding scaling law obtained from mammalian brains, children and adults which captures the relationship between exposed surface area, total surface area and cortical thickness. Cortical folding scaling was not affected by gestational age at birth, postmenstrual age at scan, sex or multiple birth in these populations. CHD was characterized by a unique reduction in the multivariate morphological term capturing size, suggesting CHD affects cortical growth overall but not cortical folding processes. In contrast, preterm birth was characterized by altered cortical folding scaling and altered shape, suggesting the developmentally programmed processes of cortical folding are disrupted in this population. The degree of altered shape was associated with cognitive abilities in early childhood in preterm infants.