The hippocampus and medial prefrontal cortex are two brain regions which have repeatedly been linked to spatial learning and memory processing; however, the precise roles of individual sub-regions within these areas continue to be debated. The Morris water maze is a well-known behavioural task used to measure spatial memory. Despite its popularity, the type of spatial information animals encode and ultimately rely on for accurate navigation in this task remains unclear. Therefore, the primary objectives of this thesis were to conduct an in-depth investigation into the use of navigation strategies during memory encoding and retrieval in the water maze, and to characterise the specific contributions of the hippocampus and medial prefrontal cortex to these processes using Immediate Early Genes (IEG) imaging. In addition, we investigated the mechanisms underlying neuronal activation by inhibiting ionotropic glutamate receptors (NMDA and AMPA) during or after spatial learning. We found novel evidence that the salience (or noticeability) of environmental cues significantly impacted the type of learning strategy used (i.e. simple or complex), and that increased training led to more flexible responding (i.e. strategy switching). We also discovered that NMDA receptor-mediated activation in area CA1 (indexed by Zif268) was tightly linked to learning-related plasticity, and activation in CA3, prelimbic and anterior cingulate cortices was strongly associated with flexible spatial memory recall (i.e. pattern completion). Finally, we revealed that spatial memory deficits induced by NMDA receptor blockade could be partially prevented by extended environmental experience
