Adult neurogenesis

Neurogenesis is the process of birth of neurons wherein neurons are generated from neural stem cells. Contrary to popular belief, neurogenesis continuously occurs in specific regions in the adult brain. Developmental neurogenesis and adult neurogenesis differ markedly. This article is limited in scope to adult neurogenesis.

In humans, new neurons are continually born throughout adulthood in two regions of the brain:

In other species of mammals, particularly rodents, adult-born neurons also appear in the olfactory bulb. In humans, however, few if any olfactory bulb neurons are generated after birth.

Much more attention has been paid to neurogenesis in the dentate gyrus than in the other areas. Many of the newborn dentate gyrus neurons die shortly after they are born, but a number of them become functionally integrated into the surrounding brain tissue. In adult humans about 700 new neurons are added in the hippocampus every day. However, the functional significance of nascent neurons remains controversial.

Adult neurogenesis poses many implications in terms of its functioning in learning and memory, emotion, stress, depression, and other conditions. This page discusses the methods utilized in studying adult neurogenesis and the possible functional roles it plays in mammals.

Neural stem cells (NSCs) are the self-renewing, multipotent cells that generate the main phenotypes of the nervous system.

The creation of new functional brain cells can be measured in several ways, summarized in the following sections.

Labelled DNA can trace dividing cell's lineage, and determine the location of its daughter cells. A nucleic acid analog is inserted into the genome of a neuron-generating cell (such as a glial cell or neural stem cell).Thymine analogs (3H) thymidine and BrdU are commonly used DNA labels, and are used for radiolabelling and respectively.

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