neuroembryology

Neuroembryology is the branch of neuroscience that studies how the nervous system develops from the fertilized egg through fetal life. It examines the formation of the brain and spinal cord, the emergence of neural components from the ectoderm, and the genetic and environmental factors that shape their organization, differentiation, and maturation.

Early development begins with neural induction, where the neural ectoderm forms the neural plate. The plate folds to create the neural tube, which gives rise to the brain and spinal cord. Neurulation proceeds in primary neurulation, which forms most brain and spinal cord, and secondary neurulation for the posterior regions.

The neural crest and cranial placodes arise at the border of the neural plate and give rise to peripheral neurons and glia, craniofacial cartilage, pigment cells, adrenal chromaffin cells, and sensory epithelia. Neural crest migration and placode development are central to vertebrate sensory and autonomic systems.

Patterning along the rostrocaudal and dorsoventral axes is controlled by signaling centers and gene networks. Signaling molecules such as SHH, BMP, WNT, and FGF gradients interact with transcription factors like PAX6, SOX2, OTX2, and NKX2-2 to specify neural identities. Notch signaling regulates the balance between progenitor maintenance and differentiation.

Disturbances in neuroembryology can produce neural tube defects (e.g., anencephaly, spina bifida) and other congenital anomalies. Folate status, teratogens, and maternal health influence risk. Model systems, from rodent embryos to chick embryos and neural organoids, illuminate conserved mechanisms of neural development.