Hippocampal heterogeneity in spatial memory revealed by cytochrome oxidase.

The oxidative metabolism was assessed in the septal, intermediate and temporal hippocampus in Wistar rats that were trained following a working memory schedule in the Morris water maze. The cytochrome oxidase histochemistry was measured at 90 min, 6, 24 and 48 h post-training. We found an increase in the septal dentate gyrus at 90 min, at 6h the increase was also found in CA3 and CA1 regions and returned to basal levels at 24h. In contrast, the intermediate region showed lower increase, limited to the dentate gyrus and CA3 at 24h post-training. No changes were found in the temporal hippocampus. These findings suggest that septal and intermediate hippocampal zones participate in this spatial learning and contribute at different moments to process this information.