| Popis: |
Once considered a structurally rigid organ, the adult mammalian brain has recently been the subject of a series of discoveries of constant remodeling at multiple levels, including synapses, dendrites, axons, and neuronal soma under physiological conditions (e.g., see a recent review by Abraham WC (2008) Metaplasticity: Tuning synapses and networks for plasticity. Nature Reviews. Neuroscience 9: 387). That there is continuous production of new neurons (neurogenesis) in the mature brain is among the recent additions to our knowledge of such structural plasticity. Moreover, recent studies have revealed the brain's previously unrecognized capacity for self-repair, that is, supply of new neurons after damage. Studies of injured brains have also revealed that endogenous neural stem/progenitor cells serve as sensitive responders to various injury signals and actively participate in tissue repair in many ways. This chapter summarizes the current understanding of this injury-induced neurogenesis in the adult mammalian brain and critically evaluates its significance in the context of brain repair. The emphasis is on the comparison between persistent and injury-induced neurogenesis and regulators and outcomes of neuronal production in damaged/diseased brains. Several important issues that remain controversial, as well as the recently emerging idea that considers stem/progenitor cells as injury sensors and responders, are also highlighted. Finally, the prospects of future research aiming at utilizing the brain's capacity for endogenous repair in the treatment of various neurological disorders are discussed. |
