The term hippocampal formation of Swanson refers to the same combination of primary structures that comprise the archicortex ( Stephan-1975 ), in this case as defined by histology in the rat ( Swanson-2004 ), It is also the same combination as in the hippocampal formation except that it includes the fasciola cinerea and and indusium griseum. Updated 5 Jun 2024.