neuroblasts

Neuroblasts are immature neurons that arise from neural precursor cells and are committed to a neuronal lineage. In vertebrate development, they originate from neural stem cells in the neural tube and surrounding regions, undergoing divisions that generate migratory neuroblasts. These cells then move to their target destinations, where they differentiate into mature neurons and integrate into developing neural circuits.

During development, neuroblasts commonly migrate along scaffolds provided by radial glial cells, using a range of guidance cues to reach the cortex, hippocampus, and other brain regions. Their fate, timing, and location shape the formation of functional neural networks and the establishment of regional connectivity.

In the adult brain, neurogenesis persists only in limited niches. Notable sites include the subventricular zone lining the lateral ventricles, where neuroblasts migrate via the rostral migratory stream to the olfactory bulb, and the dentate gyrus of the hippocampus, where granule cell precursors differentiate into granule neurons. The rate and significance of adult neurogenesis vary by species and brain region and may be influenced by aging, environment, and disease.

Molecularly, early-stage neuroblasts express markers such as doublecortin (DCX) and PSA-NCAM, transitioning to mature neurons that express NeuN and other neuronal markers. Neuroblasts are studied as models of neuronal differentiation, migration, and circuit integration, with relevance to learning, memory, and regeneration.

Clinical relevance includes the role of neuroblast proliferation and migration in developmental disorders and the occurrence of neuroblastoma, a pediatric cancer arising from precursor neural crest cells.