hippocampus morphology trait dentate gyrus morphology trait Any measurable or observable characteristic related to the shape, structure, color, or pattern of one of two interlocking gyri of the hippocampus that contains granule cells, which project to the pyramidal cells and interneurons of the CA3 region of the ammon gyrus. EFO:0009403 EFO:0010083 Trait.ontology VT:0000812