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摘要

Despite early evidence of neurogenesis in adult rodents (1), not until the 1990s was the notion fully acknowledged that new neurons could be generated in the adult brain. Newborn cells were found in humans (2), and their number was found to increase in rodents after exercise, exposure to enriched environment or learning, and decrease after stress (3). In rodent models of temporal lobe epilepsy (TLE), it was also found that status epilepticus (SE) increases neurogenesis in the dentate gyrus (4). However, instead of being a restorative process, dentate epilepsy-induced neurogenesis appeared to be detrimental: SE-newborn cells emerging from the subgranular zone were found to migrate aberrantly to the hilar/CA3 border, where they display abnormal dendritic morphology. These newborn cells-also referred to as"ectopic granule cells"-integrate functionally to the existing network and are hyperex-citable compared to normal granule cells, firing in bursts.They also contribute to mossy fiber sprouting, another hallmark of temporal lobe epilepsy (5,6).