Cell survival refers to the maintenance of new neurons and their permanent incorporation into the hippocampal circuitry. Some new granule cells survive for very long periods of time (Dayer et al., 2003) but that is not the case for all such cells produced in adulthood. In control rodents, a relatively large percentage of new neurons do not survive past a few weeks in the rodent (Dayer et al.,2003). The survival of new neurons can be influenced by environmental factors, including stress, suggesting that data on cell survival may be confounded by the relatively deprived conditions of standard laboratory life. Studies have shown that all three stages of adult neurogenesis, cell proliferation, neuronal differentiation and cell survival, can be influenced by stress, learning and environmental enrichment (Leuner & Gould, 2010) but the majority of evidence points to stress effects on cell proliferation.
