Neuroblast migration along cellular substrates in the developing porcine brain

In the past decade it has become evident that neuroblasts continue to supply the human cortex with interneurons via unique migratory streams shortly following birth. Owing to the size of the human brain, these newborn neurons must migrate long distances through complex cellular landscapes to reach their final locations. This process is poorly understood, largely because of technical difficulties in acquiring and studying neurotypical postmortem human samples along with diverging developmental features of well-studied mouse models. We reasoned that migratory streams of neuroblasts utilize cellular substrates, such as blood vessels, to guide their trek from the subventricular zone to distant cortical targets. Here, we evaluate the association between young interneuronal migratory streams and their preferred cellular substrates in gyrencephalic piglets during the developmental equivalent of human birth, infancy, and toddlerhood. • Migratory streams of neuroblasts are preserved through postnatal swine development • Evidence of young neocortical interneurons within migratory streams • Neuroblasts are tightly associated with vascular and astrocytic cellular substrates • Harm to migratory interneurons or their substrates may have lifelong consequences Porter et al. evaluated the spatiotemporal distribution of immature neurons (neuroblasts) in the subventricular zone of the postnatal piglet. Multiplex labeling revealed that migrating neuroblasts are likely cortical inhibitory interneurons originating from the ventral embryonic forebrain. These findings in the postnatal piglet provide a new platform and viewpoint for understanding neuronal migration and cortical development in normal and diseased states.