ABSTRACT
The hippocampal formation is folded archaecortex (ancient cortex) consisting of the dentate gyrus and the cornu ammonis (CA)—collectively termed the hippocampus—plus the subiculum. The cortex of the dentate gyrus and CA has three layers, while the subiculum is transitional cortex between the hippocampus proper and the six-layered neocortex of the entorhinal area. A major input to the hippocampus from the entorhinal cortex comes via the perforant pathway, axons of which synapse with granule cells of the dentate gyrus or pyramidal cells in the CA3 region of the CA (Figure 1). Axons of the granule cells (mossy fibers) also synapse with CA3 pyramidal cells.
