The goal of the study presented in the article is to map the process of fold formation in the cerebral cortex of preterm newborns. This process is also known as gyrification. To do the mapping, they applied a fast spin echo sequence through a 1.5 T magnetic resonance imaging (MRI) system, with a spatial resolution of 0.7 x 0.7 x 1.5 mm3, to each subject in a sample of 35 preterm newborns. Their gestational age was between 25.6 and 35.6 weeks, a period where the development of the human brain is critical and intense. By adapting some post-processing images tools already developed for adults and fetuses, they created a data processing method that included a segmentation of T2 weighted images of the cerebral cortex, as shown in figure 1. Thus, they obtained a 3D reconstruction of the inner cortical surface of both hemispheres, which is the interface between the cortex and the white matter zone (figure 2).

Thus, magnetic resonance imaging enabled them to map and quantify the gyrification/ folding process. They were able to define the sulcation index (SI), which quantifies the degree of the cortex folding; to evaluate its variation  with certain variables; and to observe that the gyrification process increases with gestational age. A fact that we can clearly see in both figure 1.c and figure 2.

This study highlights the potential of MRI in the study of human brain development, which can provide information regarding developmental pathologies, as some brain pathologies result from abnormalities during cortical development.

Réference: J Dubois, M Benders, A Cachia, F Lazeyras, R Ha-Vinh Leuchter, S. V. Sizonenko, C Borradori-Tolsa, J. F. Mangin, P. S. Hüppi, Mapping the Early Cortical Folding Process in the Preterm Newborn Brain, Cerebral Cortex, Volume 18, Issue 6, June 2008, Pages 1444–1454, https://doi.org/10.1093/cercor/bhm180