The bar at lower right is 6.5 mm, for scale. The hippocampus is common to many animals. Most hippocampal experiments have been performed on rats. Subsequent diagrams are of rat hippocampal regions, all of which have close analogues in the human hippocampus. Major nerve pathways through these structures are illustrated by individual neurons.
Arrows indicate the general flow of information.
6.6 CA1 and CA3 regions are inverted in humans, relative to rats. Collaterals are the synaptic junctures between axons and dendrites. Recurrent collaterals cycle inputs within the CA3 region. In Figure 6.8 the block diagram at left shows the overall information flow between regions. The diagrams in Figure 6.8 clarify Figure 6.7.