Development of Spatial Function in Rats and Associated C-Fos Patterns in the Hippocampal CA1 and CA3 Regions

The hippocampus shows connectivity-based changes during development. The current work investigated the contribution of performance and cognitive factors in the emergence of spatial function during development. Experiment one showed a sensitive developmental period exists between 16 days old (p16) and p24. Experiment two found impaired performance on spatial learning following NMDAr blockade. Experiment three explored one-day of water maze training at p16, p18, or p20 and spatial learning was established only at p20. Quantification of c-Fos positive cells in CA3 and CA1 revealed a main effect of age. Lastly, rats were trained on the dry maze at: p16, p17, p18, p19, or p20. Groups p19 and p20 demonstrated spatial learning. Quantification of c-Fos positive cells in CA1 revealed a main effect of age. This suggests that spatial memory mechanisms emerge at p19/p20 independently from performance factors and are based on hippocampal function.