The Morris water maze has been extensively used in the study of spatial learning and
memory, and a number of hippocampal, parahippocampal and neocortical brain regions
have been identified as necessary for successful performance in this task. Immediate
Early Genes (IEGs) have been implicated in learning and memory processes, and are
used as markers of neural activity in a brain region in response to learning tasks. The use
of adequate control conditions in these tasks has been identified as important, and we
devised a novel control condition in an attempt to address these concerns. We examined
the expression of IEGs over the course of spatial learning, finding that Zif268 expression
was upregulated in a number of regions during early learning, and that c-Fos was
upregulated during late learning. We investigated the role of IEGs in cellular
consolidation at different time-points in the hours following learning, but we did not find
support for multiple waves of IEG expression as previously reported in the literature. We
also examined the course of systems consolidation by analysing IEG expression during
recent and remote memory probe trials. The hippocampus was equivalently or
increasingly activated over the course of time reflecting its continued involvement, while
widespread increases in cortical activity were observed at remote time-points, consistent
with systems consolidation theories. In addition, we showed that IEG expression was
associated with error correction during learning and with superior performance during
retention
