新研究表明特定區(qū)域的腦中,，新生神經元在早期發(fā)育過程中的經歷,，會影響它們在成年腦中的存活和活性,。這些新生神經元存儲這些經歷的方式,，可以用以解釋它們如何影響成年個體學習和記憶的過程,。美國Salk研究所的Fred Gage領導研究小組完成了此項研究。
研究者發(fā)現：經歷可以加強腦中齒狀回（*）區(qū)域的新生神經元的存活,，而且相同經歷的出現會激活更多這類的神經元,。這種功能上的轉變可能是長期記憶（**）的內在機制。研究文章發(fā)表在3月21日的《The Journal of Neuroscience》雜志上,。
“研究結果識別出了一個特定的時期,，在這個時期經歷可以增強海馬（***）中新生神經元的存活，”普林斯頓大學的Elizabeth Gould介紹說,，他沒有參與此項研究,。海馬包括齒狀回這一區(qū)域。
Gage介紹說：“今后的研究將會致力于在記憶相關的行為過程中,，經歷是如何影響神經元的活性的，以及這對于其他的腦區(qū)域有何影響,。”感興趣的讀者可以參看英文原文,。
部分英文原文：
The Journal of Neuroscience, March 21, 2007, 27(12):3252-3259; doi:10.1523/JNEUROSCI.4941-06.2007
Experience-Specific Functional Modification of the Dentate Gyrus through Adult Neurogenesis: A Critical Period during an Immature Stage
Ayumu Tashiro, Hiroshi Makino, and Fred H. Gage
Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037
Correspondence should be addressed to Fred H. Gage, 10010 North Torrey Pines Road, La Jolla, CA 92037. Email: [email protected]
Neural circuits in the dentate gyrus are continuously modified by adult neurogenesis, whose level is affected by the animal's experience. However, it is not known whether this experience-dependent anatomical modification alters the functional properties of the dentate gyrus. Here, using the expression of immediate early gene products, c-fos and Zif268, as indicators of recently activated neurons, we show that previous exposure to an enriched environment increases the total number of new neurons and the number of new neurons responding to reexposure to the same environment. The increase in the density of activated new neurons occurred specifically in response to exposure to the same environment but not to a different experience. Furthermore, we found that these experience-specific modifications are affected exclusively by previous exposure around the second week after neuronal birth but not later than 3 weeks. Thus, the animal's experience within a critical period during an immature stage of new neurons determines the survival and population response of the new neurons and may affect later neural representation of the experience in the dentate gyrus. This experience-specific functional modification through adult neurogenesis could be a mechanism by which new neurons exert a long-term influence on the function of the dentate gyrus related to learning and memory.
Key words: enriched environment; c-fos; zif268; immediate early gene; dentate gyrus; hippocampus; memory; neurogenesis
