研究人員在日前在線出版的《自然—神經(jīng)科學(xué)》期刊上報(bào)告,，成年大腦需要持續(xù)不斷的新生神經(jīng)細(xì)胞來(lái)維持嗅覺(jué)和空間探索等區(qū)域的功能。
直至最近幾年前,，一種流行的觀點(diǎn)還認(rèn)為,，成年大腦會(huì)漸漸失去神經(jīng)細(xì)胞，卻不會(huì)生長(zhǎng)新的神經(jīng)細(xì)胞,。如今,，這種觀點(diǎn)已經(jīng)被顛覆，但科學(xué)家們還是不知道少數(shù)新產(chǎn)生的神經(jīng)細(xì)胞究竟會(huì)發(fā)揮什么樣的重要作用,。
Ryoichiro Kageyama和同事探討了這個(gè)問(wèn)題,。通過(guò)基因工程改造，他們培養(yǎng)出一種小鼠,，這種小鼠會(huì)在所有成年時(shí)出生的神經(jīng)細(xì)胞中合成了一種熒光蛋白質(zhì),，他們?cè)谝荒甑臅r(shí)間中記錄了熒光神經(jīng)細(xì)胞的數(shù)量。在這一時(shí)間段里,，在嗅球細(xì)胞某一層中的神經(jīng)細(xì)胞基本被新細(xì)胞完全置換了,。大腦的海馬區(qū)域?qū)臻g學(xué)習(xí)和記憶至關(guān)重要，這一區(qū)域也新增加大約15%的新細(xì)胞,。
中止神經(jīng)細(xì)胞的生長(zhǎng)是否會(huì)影響小鼠的嗅覺(jué)和學(xué)習(xí)能力呢,？Kageyama和同事培育了另一種類(lèi)的小鼠，它們會(huì)在成年神經(jīng)細(xì)胞的前體中生成一種有毒蛋白質(zhì),，從而殺死新生細(xì)胞。沒(méi)有了新細(xì)胞，小鼠的嗅球變小了,，但它們的嗅覺(jué)能力在4個(gè)月的時(shí)間時(shí)維持不變,，說(shuō)明這一區(qū)域有多余細(xì)胞。相反,，指導(dǎo)小鼠在迷宮里導(dǎo)航的記憶能力卻消失了,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature Neuroscience，doi:10.1038/nn.2185,，Itaru Imayoshi,，Ryoichiro Kageyama
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.
1 Institute for Virus Research, Kyoto University, Shogoin-Kawahara, Sakyo-ku, Kyoto 606-8507, Japan.
2 Kyoto University Graduate School of Biostudies, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501, Japan.
3 Japan Science and Technology Agency, CREST, Shogoin-Kawahara, Sakyo-ku, Kyoto 606-8507, Japan.
4 Kyoto University Graduate School of Medicine, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501, Japan.
5 Fujita Health University, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan.
6 Institute for Bioinformatics Research and Development and CREST, 4-1-8, Honcho, Kawaguchi, Saitama 332-0012, Japan.
7 Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
8 RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
9 Present address: National Institute for Longevity Sciences, 36-3, Gengo, Morioka, Obu, Aichi 474-8511, Japan.
