早期經(jīng)歷能提高大腦適應(yīng)未來類似事件的能力，這是常識,，但最初的經(jīng)歷是怎樣在神經(jīng)回路中表達的、或者說它對再學(xué)習(xí)有何貢獻卻不清楚。實驗鼠一只眼睛的臨時閉合這樣一個模型為研究這些問題提供了一個體系。新的經(jīng)歷（即單眼視覺）誘導(dǎo)來自視覺皮層中神經(jīng)細胞的樹突棘的生長,。
通過交替單眼視覺和雙眼視覺的時間段以及對神經(jīng)細胞的形態(tài)進行幾天時間的跟蹤，Hofer等人得以能夠記錄到由經(jīng)歷所誘導(dǎo)的結(jié)構(gòu)變化,，并發(fā)現(xiàn)它們的持續(xù)時間是否能夠超過經(jīng)歷本身,。他們發(fā)現(xiàn)，長壽命的樹突棘密度隨單眼視覺的喪失而增加,，其持續(xù)時間超過經(jīng)歷的持續(xù)時間,。隨后再使視覺喪失卻未能誘導(dǎo)樹突棘密度進一步增加，說明最初經(jīng)歷可能會提供一個結(jié)構(gòu)性經(jīng)歷的“蹤跡”,，該“蹤跡”在對進一步的功能性變化做出反應(yīng)時可被利用,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 457, 313-317 (15 January 2009) | doi:10.1038/nature07487
Experience leaves a lasting structural trace in cortical circuits
Sonja B. Hofer1,2, Thomas D. Mrsic-Flogel1,2, Tobias Bonhoeffer1 & Mark Hübener1
1 Max Planck Institute of Neurobiology, D-82152 Martinsried, Germany
2 Present address: Department of Physiology, University College London, London WC1 6JJ, UK.
Sensory experiences exert a powerful influence on the function and future performance of neuronal circuits in the mammalian neocortex1, 2, 3. Restructuring of synaptic connections is believed to be one mechanism by which cortical circuits store information about the sensory world4, 5. Excitatory synaptic structures, such as dendritic spines, are dynamic entities6, 7, 8 that remain sensitive to alteration of sensory input throughout life6, 9. It remains unclear, however, whether structural changes at the level of dendritic spines can outlast the original experience and thereby provide a morphological basis for long-term information storage. Here we follow spine dynamics on apical dendrites of pyramidal neurons in functionally defined regions of adult mouse visual cortex during plasticity of eye-specific responses induced by repeated closure of one eye (monocular deprivation). The first monocular deprivation episode doubled the rate of spine formation, thereby increasing spine density. This effect was specific to layer-5 cells located in binocular cortex, where most neurons increase their responsiveness to the non-deprived eye3, 10. Restoring binocular vision returned spine dynamics to baseline levels, but absolute spine density remained elevated and many monocular deprivation-induced spines persisted during this period of functional recovery. However, spine addition did not increase again when the same eye was closed for a second time. This absence of structural plasticity stands out against the robust changes of eye-specific responses that occur even faster after repeated deprivation3. Thus, spines added during the first monocular deprivation experience may provide a structural basis for subsequent functional shifts. These results provide a strong link between functional plasticity and specific synaptic rearrangements, revealing a mechanism of how prior experiences could be stored in cortical circuits.
