Developmental Pattern of Individual Morphometric Similarity Network in the Human Fetal Brain

The development of cerebral cortex during the fetal period is complex yet well-coordinated. MRI-based morphological brain network provides a powerful tool for describing this process at a network level. Due to the challenges of in-utero MRI acquisition and image processing, the fetal brain morphological network has not been established. In this study, utilizing high-resolution in-utero MRI image, we constructed individual morphometric similarity network for each fetus based on multiple cortical features and characterized the spatiotemporal changes of morphological connections and the network topology. Edge analysis demonstrated a decline of morphological symmetry between hemispheres, especially for the parietal cortex. The limbic and parieto-occipital regions exhibited the most drastic changes of network connections. Graph theoretical analysis indicated that the small-world structure of the network appeared as early as 22 weeks and that the network topology exhibited an enhanced integration and reduced segregation during the prenatal period. In summary, this study provides an important evidence for understanding the normal development of fetal brain connectome during second-third trimester.