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The scholarpedia article on this subject says:

Adult neurogenesis is the process of generating new neurons which integrate into existing circuits after fetal and early postnatal development has ceased. In most mammalian species, adult neurogenesis only appears to occur in the olfactory bulb and the hippocampus.

The Scholarpedia entry is dated 2007. Has there any more recent evidence been uncovered showing adult neurogenesis in other parts of the brain? If it is linked to brain plasticity, surely it would be useful to many more areas?

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You are right that active adult neurogenesis is generally considered to be restricted to the dentate gyrus of the hippocampus, and the subventricular zone of the lateral ventricles. The latter generates neurons that subsequently migrate through the rostral migratory stream to the olfactory bulb to become interneurons (Ming & Song, 2011).

Although the hippocampus is critical for the formation of memory, hippocampal neurogenesis does not simply 'add memory' (Kemperman, 2002). Instead, hippocampal neurogenesis is believed to mediate the continuing modulation of cortical functions in response to exposure to novelty (Aimone et al., 2014). Specific examples are spatial-navigation learning and long-term spatial memory retention, spatial pattern discrimination and contextual fear conditioning. Adult olfactory bulb neurogenesis is associated with maintaining long-term structural integrity of the olfactory bulb, short-term olfactory memory, olfactory fear conditioning, and long-term associative olfactory memory involving active learning (Ming & Song, 2011).

Neurogenesis in other regions in the adult brain are generally believed to be limited under normal physiological conditions, but can be reproducibly induced after inflicting injury to the grain (Gould, 2007). These regions include the neocortex, amygdala, hypothalamus, substantia nigra and the brainstem, among other regions (see Fig. 1). Regions of neurogenesis
Fig. 1. Regions of neurogenesis in mammals, shown in a rat's brain. The red regions (hippocampus & subventricular zone of the lateral ventricles) are considered to be neurogenic. The other regions may also be neurogenic, but only reproducibly so in experiments after damage to these regions. Source: Gould (2007).

References
- Aimone et al., Physiol Rev (2014); 94: 991–1026
- Gould, Nature Rev Neurosci (2007); 8 481-8
- Kemperman, J Neurosci (2002); 22(3): 635-8
- Ming & Song, Neuron (2011); 70(4): 687–702

Related question
- What evidence is there that the adult brain can produce new neurons?

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  • $\begingroup$ Thanks. As a follow up question, would you know what it is about these two regions in particular that makes them able to benefit from neurogenesis, while it doesn't seem to be required in other regions? Is there anything that these two regions have in common that separates them from other regions (from an information-processing perspective)? $\endgroup$ – Joebevo Aug 21 '15 at 2:42
  • $\begingroup$ @Joebevo - my pleasure. Please see my edits above for the functional implication of hippocampal and subventricular neurogenesis. $\endgroup$ – AliceD Aug 21 '15 at 12:17
  • $\begingroup$ I read the Kemperman paper, and he says that neurogenesis is more widespread across brain regions in birds than in adult mammals. He also seems to say that studies on birds have been made in environments that may have been richer. There seems to be a connection between the richness of the environment and the extent of the neurogenesis. Do you think experiments in richer environments will yield more widespread neurogenesis in adult mammals? $\endgroup$ – Joebevo Aug 22 '15 at 13:12
  • $\begingroup$ @Joebevo, I don't know, but it sounds like a great question to me. $\endgroup$ – AliceD Jan 16 at 7:03

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