Neuroblast

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A neuroblast is a divisible neuronal precursor cell that develops into a no longer divisible young neuron , which then - often only after a certain time and a migration - finally differentiates into a (mature) neuron under the influence of its environment .

Like glioblasts , neuroblasts arise from poorly differentiated neural stem cells , which form the walls of the neural tube as neuroepithelium in the embryonic development phase . First, at the beginning of the 5th week of development in humans, they form a single-layer epithelium as a ventricular zone and occupy the entire wall thickness of the later CNS , between the ventricular inner surface around the neural tube clearing and the outer mesenchymal surface (later pia mater ). These stem cells divide (proliferation), and after mitosis, both daughter cells usually each send a basal and an apical cell extension, which make contact at the inner and outer interfaces. Then the soma of these bipolar cells containing the nucleus moves up and down between the two processes . The apical processes then form an outer marginal zone (edge ​​zone) if they are not withdrawn and the cell is rounded off in order to divide again. From these cell divisions stem cells emerge again, as well as - after a few mitotic cycles - the precursor cells of both nerve cells and glial cells.

Later, cells that no longer go through a mitotic cycle, mostly young neurons, move their cell nucleus to a middle position and thus form an intermediate zone . Other cells occupy a position between this and the ventricular zone and continue to divide. This population thus forms a subventricular zone . Further cells in the area of ​​the future brain between the intermediate zone and marginal zone form a further row of cells, called a cortical plate . Then numerous (young) neurons migrate out of the ventricular zone, mostly along the guide structures formed by radial glia , some also tangentially across them.

Even after birth, not only in other mammals , but also in humans, new neurons can still be formed - with similar conditions in the so-called subventricular zone , as well as in regions of the hippocampus and the subcortical white matter - as adult neurogenesis .

Individual evidence

  1. ↑ D. Purves, G. Augustine, D. Fitzpatrick: Neuroscience . 2nd edition. Sinauer Associates, 2001, Neuronal Migration .
  2. ↑ D. Clarke: Neural stem cells . In: Bone Marrow Transplant . Volume 32, No. (S) 1, 2003, pp. 13-17. PMID 12931233 .
  3. ↑ M. Götz, W. Huttner: The cell biology of neurogenesis . In: Nat Rev Mol Cell Biol . Volume 6, No. 10, 2005, pp. 777-788. PMID 16314867 .
  4. ↑ Benninghoff: Macroscopic and microscopic anatomy of humans, Vol. 3. Nervous system, skin and sensory organs . Urban and Schwarzenberg, Munich 1985, ISBN 3-541-00264-6 , p. 66ff.
  5. ^ J. Cooper: Mechanisms of cell migration in the nervous system . In: Journal Cell Biology . Volume 202, No. 5, September 2013, pp. 725-734. doi : 10.1083 / jcb.201305021 .
  6. ↑ C. Cooper-Kuhn: Regulation of neurogenesis in the adult mammalian brain. Dissertation, University of Regensburg, 2003.
  7. ^ S. Goldman, F. Sim: Neural progenitor cells of the adult brain . In: Novartis Found Symposion . Volume 265, 2005, pp. 66-80. PMID 16050251 .
  8. ^ P. Eriksson and team: Neurogenesis in the adult human hippocampus. In: Nature Medicine 4, 1998, pp. 1313-1317. PMID 9809557 .
  9. ↑ M. Nunes and team: Identification and isolation of multipotential neural progenitor cells from the subcortical white matter of the adult human brain. In: Nature Medicine 9, 2003, pp. 439-447. PMID 12627226 .