[3] It is formed at borders between archicortex (a subtype of allocortex) and isocortex and shows slow histological transition from the four-layered structure typical for archicortex to the six-layered structure typical for isocortex.
[1] Periarchicortex does not contact immediately at borders with the true isocortex and does not transit directly into it.
Instead, another transitional area from the isocortex side, called proisocortex, is formed at such borders.
One such area, which is anatomically located closer to the archicortex side and histologically more resembling it, is called periarchicortex.
[1] Another transitional area, which is anatomically located closer to the true isocortex and histologically more resembling it, is called proisocortex.