Kempermann Gerd, Song Hongjun, Gage Fred H
German Center for Neurodegenerative Diseases (DZNE) Dresden and CRTD-Center for Regenerative Therapies Dresden at Technische Universität Dresden, 01307 Dresden, Germany.
Institute for Cell Engineering, Stem Cell Program at ICW, The John Hopkins University, Baltimore, Maryland 21205.
Cold Spring Harb Perspect Biol. 2015 Sep 1;7(9):a018812. doi: 10.1101/cshperspect.a018812.
Of the neurogenic zones in the adult brain, adult hippocampal neurogenesis attracts the most attention, because it is involved in higher cognitive function, most notably memory processes, and certain affective behaviors. Adult hippocampal neurogenesis is also found in humans at a considerable level and appears to contribute significantly to hippocampal plasticity across the life span, because it is regulated by activity. Adult hippocampal neurogenesis generates new excitatory granule cells in the dentate gyrus, whose axons form the mossy fiber tract that links the dentate gyrus to CA3. It originates from a population of radial glia-like precursor cells (type 1 cells) that have astrocytic properties, express markers of neural stem cells and divide rarely. They give rise to intermediate progenitor cells with first glial (type 2a) and then neuronal (type 2b) phenotype. Through a migratory neuroblast-like stage (type 3), the newborn, lineage-committed cells exit the cell cycle and enter a maturation stage, during which they extend their dendrites into a the molecular layer and their axon to CA3. They go through a period of several weeks, during which they show increased synaptic plasticity, before finally becoming indistinguishable from the older granule cells.
在成人大脑中的神经源性区域中，成体海马神经发生最受关注，因为它参与更高层次的认知功能，最显著的是记忆过程以及某些情感行为。在人类中也发现成体海马神经发生处于相当可观的水平，并且似乎在整个生命周期中对海马可塑性有显著贡献，因为它受活动调节。成体海马神经发生在齿状回中产生新的兴奋性颗粒细胞，其轴突形成将齿状回与CA3相连的苔藓纤维束。它起源于一群具有星形胶质细胞特性、表达神经干细胞标志物且很少分裂的放射状胶质样前体细胞（1型细胞）。它们产生具有首先是胶质（2a型）然后是神经元（2b型）表型的中间祖细胞。通过类似迁移神经母细胞的阶段（3型），新生的、已确定谱系的细胞退出细胞周期并进入成熟阶段，在此期间它们将树突延伸到分子层并将轴突延伸到CA3。它们经历几周的时间，在此期间它们表现出增强的突触可塑性，最终变得与较老的颗粒细胞难以区分。
