Differential mRNA expression as a function of spatial behavior. Changes in level of transcript were determined by real-time RT-PCR as described in Materials and Methods. Compared to swim control animals (n = 2), spatially trained rats (n = 6) had higher levels of gene transcript in the hippocampus 30 minutes following training in the spatial paradigm. [PCR CT values: homer1a (t(21) = 6.07, p < 0.0001); c-fos (t(22) = 7.121, p < 0.0001); zif268 (t(22) = 7.601, p < 0.0001)]. Fold-changes: homer1a = 2.6, zif268 = 3.8, c-fos = 1.8.