von Hertzen Laura S J, Giese K Peter
Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom.
J Neurosci. 2005 Feb 23;25(8):1935-42. doi: 10.1523/JNEUROSCI.4707-04.2005.
The relationship between memory consolidation and reconsolidation at the molecular level is poorly understood. Here, we identify three immediate-early genes that are differentially regulated in the mouse hippocampus after contextual fear conditioning and reactivation of the context-shock memory: serum- and glucocorticoid-induced kinase 1 (SGK1), SGK3, and nerve growth factor-inducible gene B (NGFI-B). The upregulation of SGK1 expression was not specific for the context-shock association and therefore not suitable for a comparison of contextual memory consolidation and reconsolidation. SGK3 expression was upregulated during both consolidation and reconsolidation. Analysis of SGK3 expression showed that expression changes elicited by a context-shock association during consolidation can subsequently be recapitulated during reconsolidation and that the transcriptional changes induced by retrieval depend on the remoteness of the memory. On the other hand, we found that NGFI-B is regulated during consolidation but not reconsolidation. This consolidation-specific regulation occurs in hippocampal area CA1. Our discovery of a consolidation-specific transcription indicates that reconsolidation is only a partial recapitulation of consolidation at the transcriptional level. Such partial rather than total recapitulation may have evolved as a more economic and reliable mechanism for organisms to modify memory.
在分子水平上，记忆巩固与再巩固之间的关系仍知之甚少。在此，我们鉴定出三个立即早期基因，它们在情境恐惧条件反射以及情境-电击记忆再激活后，在小鼠海马体中受到不同程度的调控：血清和糖皮质激素诱导激酶1（SGK1）、SGK3以及神经生长因子诱导基因B（NGFI-B）。SGK1表达的上调并非情境-电击关联所特有，因此不适用于比较情境记忆的巩固和再巩固。SGK3的表达在巩固和再巩固过程中均上调。对SGK3表达的分析表明，巩固过程中由情境-电击关联引发的表达变化在再巩固过程中可被重现，且检索诱导的转录变化取决于记忆的久远程度。另一方面，我们发现NGFI-B在巩固过程中受到调控，但在再巩固过程中不受调控。这种特定于巩固的调控发生在海马体CA1区。我们对特定于巩固的转录的发现表明，再巩固只是在转录水平上对巩固的部分重现。这种部分而非完全的重现可能已经演变为生物体修改记忆的一种更经济、更可靠的机制。
