日本京都大學研究人員在新一期《自然·神經(jīng)學》雜志網(wǎng)絡版上報告說，維持空間記憶能力需要腦神經(jīng)細胞不斷更新,，否則就會成為“路癡”,。這項成果有助于探究記憶障礙的原因。
研究人員認為,，大多數(shù)腦神經(jīng)細胞都是在胎兒期和生長期由神經(jīng)干細胞分化而來,，即使到了成年，大腦內(nèi)部掌管空間辨別等復雜記憶的中樞——“海馬齒狀回”等部位的干細胞仍能分化神經(jīng)細胞,，幫助學習和記憶,。京都大學教授影山龍一郎等人利用一種能檢測、標識新生腦神經(jīng)細胞的技術,，從實驗鼠出生2個月后就對它們的大腦進行研究,。結(jié)果發(fā)現(xiàn)，“海馬齒狀回”的神經(jīng)細胞在8個月內(nèi)數(shù)量增加了約15％,。
研究人員又對比研究因人為原因不能生成新的腦神經(jīng)細胞的實驗鼠,，觀察對其認路能力的影響。他們在一張圓桌上挖了12個洞,，只在其中一個洞的下面放置了箱子,。正常實驗鼠一般1周后就能記住下方有箱子的洞的位置，而這些實驗鼠卻始終難以做到,。（生物谷Bioon.com）
生物谷推薦原始出處：
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.
