What is neurogenesis


English: neurogenesis

1 definition

The Neurogenesis describes the formation of nerve cells from precursor cells or stem cells during the embryonic period or in the adult nervous system.

2 Embryonic neurogenesis

Embryonic neurogenesis encompasses the entire development from the secretion of the neural crest cells and the formation of the first brain vesicles to the differentiation of the nervous system and the actual innervation of the body. Neurogenesis begins in the early stages of embryogenesis with the formation of the neural tube, which separates from the ectoderm. This process of neurulation lays the foundation for the further development of the brain and spinal cord.

The three cerebral vesicles develop from the cranial parts of the neural tube, from which the fore, middle and hindbrain later develop. These vesicles are already created between the 20th and 25th day of development. The spinal cord arises from the caudal parts of the neural tube.

3 Adult neurogenesis

Until the end of the 20th century, the formation of new nerve cells in the CNS of the adult organism was thought to be impossible. Only then did it become apparent that the adult brain also has a stem cell reservoir. Adult neurogenesis essentially takes place in the CNS in two places:

Neural stem cells have a high density of voltage-independent potassium channels and have no voltage-dependent sodium channels - they are therefore not electrically excitable. Morphologically they resemble radial astroglial cells.

The function of adult neurogenesis has not yet been conclusively clarified. Among other things, they are assigned an important role in the formation of long-term memory. Decreased neurogenesis has been linked to the development of Alzheimer's disease.