Prenatal growth of the human cerebral cortex: brainprint analysis

To construct a series of flat maps (brainprints) that document the prenatal growth of human cerebral cortex and help identify sulcal landmarks for division of cortical regions of interest (ROIs) on mapped surfaces, the authors photographed and traced histologic whole-brain slices of 25 normal human fetal brains aged 18-42 weeks gestation. Brainprints of both cerebral hemispheres from each fetus were constructed with semiautomatic brain-mapping software, and each map was divided into five ROIs based on sulcal landmarks: frontal, parietal, insular, occipital, and temporal cortices. Surface areas of cerebral hemispheres and the five ROIs were estimated. Corrected for histologic shrinkage, brainprint estimates of human fetal cortical surface area were approximately twice those of previous estimates. Cortical lobe proportions at 18 weeks appeared to be unchanged to term. Surface area estimates correlated with fetal age, brain weight, and brain volume. This collection of cortical maps may guide future quantitative analyses of cerebral hemispheric growth in premature and term infants who undergo magnetic resonance imaging, which may, in turn, help predict neurobehavioral outcomes of early cortical damage.