The hippocampus is required for many forms of long-term memory in both humans and animals1, and formation of long-lasting memories requires the synthesis of new proteins2. Furthermore, the long-term potentiation (LTP) of hippocampal synapses, a widely studied model of memory, also depends on both de novo gene transcription and protein synthesis3 and results in the activation of transcription from promotors containing the cAMP response element (CRE)4. Expression of several genes is induced during the establishment of LTP; these include the immediate-early genes (IEGs) BDNF (brain-derived neurotrophic factor), zif268 and C/EBP (CCAAT-enhancer binding protein ), all of which contain CRE sites within their promotor regions3,
5. However, these genes induced by LTP are not known to be rapidly induced following learning in a natural setting. Here we demonstrate rapid and selective induction of BDNF expression during hippocampus-dependent contextual learning.
(CCAAT-enhancer binding protein 
