日本京都大学研究人员在新一期《自然·神经学》杂志网络版上报告说，维持空间记忆能力需要脑神经细胞不断更新，否则就会成为“路痴”。这项成果有助于探究记忆障碍的原因。
研究人员认为，大多数脑神经细胞都是在胎儿期和生长期由神经干细胞分化而来，即使到了成年，大脑内部掌管空间辨别等复杂记忆的中枢——“海马齿状回”等部位的干细胞仍能分化神经细胞，帮助学习和记忆。京都大学教授影山龙一郎等人利用一种能检测、标识新生脑神经细胞的技术，从实验鼠出生2个月后就对它们的大脑进行研究。结果发现，“海马齿状回”的神经细胞在8个月内数量增加了约15％。
研究人员又对比研究因人为原因不能生成新的脑神经细胞的实验鼠，观察对其认路能力的影响。他们在一张圆桌上挖了12个洞，只在其中一个洞的下面放置了箱子。正常实验鼠一般1周后就能记住下方有箱子的洞的位置，而这些实验鼠却始终难以做到。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature Neuroscience Published online: 31 August 2008 | doi:10.1038/nn.2185
Roles of continuous neurogenesis in the structural and functional integrity of the adult forebrain
Itaru Imayoshi1,2,3, Masayuki Sakamoto1,2, Toshiyuki Ohtsuka1,3, Keizo Takao4,5,6, Tsuyoshi Miyakawa4,5,6, Masahiro Yamaguchi7, Kensaku Mori7, Toshio Ikeda8,9, Shigeyoshi Itohara8 & Ryoichiro Kageyama1,3
Abstract
Neurogenesis occurs continuously in the forebrain of adult mammals, but the functional importance of adult neurogenesis is still unclear. Here, using a genetic labeling method in adult mice, we found that continuous neurogenesis results in the replacement of the majority of granule neurons in the olfactory bulb and a substantial addition of granule neurons to the hippocampal dentate gyrus. Genetic ablation of newly formed neurons in adult mice led to a gradual decrease in the number of granule cells in the olfactory bulb, inhibition of increases in the granule cell number in the dentate gyrus and impairment of behaviors in contextual and spatial memory, which are known to depend on hippocampus. These results suggest that continuous neurogenesis is required for the maintenance and reorganization of the whole interneuron system in the olfactory bulb, the modulation and refinement of the existing neuronal circuits in the dentate gyrus and the normal behaviors involved in hippocampal-dependent memory.
