影响记忆和情绪的干细胞

　　

生物通报道：大脑是如何调节记忆和情绪的？最近，由于两种不同类型干细胞的发现，科学家们对此有了更进一步的了解。相关研究结果发表在五月二十七日的《Journal of Neuroscience》。延伸阅读：Nature：大脑恐惧记忆从何而来？。

在这项研究中个，昆士兰大学的研究人员在海马体中发现了两种干细胞，海马体是对学习和记忆非常关键的大脑区域。该研究的第一作者Dhanisha Jhaveri博士称，昆士兰脑研究所（QBI）的研究人员已经首次分离得到了这些细胞的纯群体。

这一发现可能对于学习和情绪有关的疾病治疗，有着深远的影响。Jhaveri博士说，我们发现的这些干细胞，可产生新的神经元。

大脑中新神经元的生成，是学习和认知功能所必不可少的，这个过程会随着我们年龄的增长而衰退。

昆士兰脑研究所所长Perry Bartlett教授说，这个研究结果，解决了关于“海马体中新生神经元产生”的一个长期未解之谜。他指出，以前这些神经元被认为都是相同的，所以我们不了解该区域如何能够调节像学习和情绪这样不同的行为。不同干细胞群的存在表明，它们可产生不同类型的神经元，这解释了海马体各种各样的功能。

Jhaveri博士说，研究人员采用最先进的细胞分选和DNA技术，获得了这些研究结果。她解释说，两组细胞位于海马体的不同区域，这表明，是海马内的不同区域控制着空间学习与情绪。当他们纯化这些细胞时，我们发现它们是由不同的机制激活，并生成在基因表达上不同的新神经细胞。

（生物通：王英）

生物通推荐原文摘要：
Purification of Neural Precursor Cells Reveals the Presence of Distinct, Stimulus-Specific Subpopulations of Quiescent Precursors in the Adult Mouse Hippocampus
Abstract: The activity of neural precursor cells in the adult hippocampus is regulated by various stimuli; however, whether these stimuli regulate the same or different precursor populations remains unknown. Here, we developed a novel cell-sorting protocol that allows the purification to homogeneity of neurosphere-forming neural precursors from the adult mouse hippocampus and examined the responsiveness of individual precursors to various stimuli using a clonal assay. We show that within the Hes5-GFP+/Nestin-GFP+/EGFR+ cell population, which comprises the majority of neurosphere-forming precursors, there are two distinct subpopulations of quiescent precursor cells, one directly activated by high-KCl depolarization, and the other activated by norepinephrine (NE). We then demonstrate that these two populations are differentially distributed along the septotemporal axis of the hippocampus, and show that the NE-responsive precursors are selectively regulated by GABA, whereas the KCl-responsive precursors are selectively modulated by corticosterone. Finally, based on RNAseq analysis by deep sequencing, we show that the progeny generated by activating NE-responsive versus KCl-responsive quiescent precursors are molecularly different. These results demonstrate that the adult hippocampus contains phenotypically similar but stimulus-specific populations of quiescent precursors, which may give rise to neural progeny with different functional capacity.