The dentate gyrus, like the hippocampus, consists of three distinct layers: an outer molecular layer, a middle granule cell layer, and an inner polymorphic layer.[11] (In the hippocampus the outer layer is the molecular layer, the middle layer is the pyramidal layer, and the inner layer the stratum oriens). The polymorphic layer is also the hilus of the dentate gyrus, (CA4, the junction of the hippocampus and dentate gyrus).[12][13]