Figure 1.

The pattern of zif268 expression in the dentate gyrus (DG) is altered by recent experience. Representative montages of confocal images taken across the DG (scale bar = 200 μm) demonstrate that the number of granule cells expressing zif268 in caged control animals (a) taken directly from their home cages is very low (<1%) in both blades of the DG, while spatial exploration (b) induces a robust increase in zif268 transcription localized primarily in the suprapyramidal (SP) blade and not the infrapyramidal (IP) blade. Higher magnification confocal micrographs of the suprapyramidal blade (scale bar = 60 μm) are also shown to illustrate the differences in the pattern of zif268 transcription in the three behavioural conditions implemented in the current study. Relative to caged controls (c), the DG of animals killed immediately following spatial exploration (d, immediate) show significantly more granule cells (~5%) expressing zif268 within the nucleus (short arrow). Animals killed 25 min after exploration (e, delay) show comparable levels of zif268 expression to the immediate group, but the majority of mRNA is within the cytoplasm of granule cells (long arrow). Granule cell nuclei are counterstained with DAPI (blue) and zif268 is labeled with Cy3 (red).