Table 4.

Increase in Arc RNA expression in CA1, CA3, and dentate gyrus of rats trained in the spatial water task

Region	Relative Arc expression (%)
Dentate gyrus	150  ± 9
CA1	261  ± 33
CA3	200  ± 36

The reported percentages are given relative to caged control rats. Four sections containing the dorsal hippocampus and processed forArc RNA signal using FISH were analyzed for each rat. For CA1 and CA3 regions, Arc fluorescent intensity was determined over the appropriate region of the pyramidal cell layer. For the dentate gyrus, Arc RNA-positive cells in the granule cell layer were counted. The total mean number ofArc-positive dentate cells per rat was 92 for the caged control group and 138 for the water task-trained group. See Materials and Methods for details on the FISH and normalization procedures.n = 3 rats per group.