Editing Archicortex (section)

{{short description|Phylogenetically oldest part of the cerebral cortex or pallium}}
{{Infobox Brain
| Name            = Archicortex
| Latin           = archicortex
| Image           = CajalHippocampus (modified).png
| Caption         = The archicortex in humans is a synonym of the [[hippocampal formation]]. The hippocampal formation is shown here, as drawn by [[Santiago Ramon y Cajal]]: DG: dentate gyrus. Sub: subiculum. EC: entorhinal cortex. CA1-CA3: hippocampus proper
| Image2          =
| Caption2        =
| IsPartOf        = [[cerebral cortex]] or [[pallium]]
| System          = [[Olfactory system]]
}}

The '''archicortex''', or '''archipallium''', is the [[Phylogenetics|phylogenetically]] second oldest region of the [[brain]]'s [[cerebral cortex]] (the oldest is the [[paleocortex]]). In older species, such as fish, the archipallium makes up most of the [[telencephalon|cerebrum]]. [[Amphibian]]s develop an archipallium and [[paleopallium]]. 

In humans, the archicortex makes up the three [[cortical layer]]s of the [[hippocampus]].<ref name="Purves1">{{cite book |last1=Purves |first1=Dale |title=Neuroscience |date=2012 |location=Sunderland, Mass. |isbn=9780878936953 |page=731 |edition=5th}}</ref> It has fewer [[cortical layer]]s than both the [[neocortex]], which has six, and the [[paleocortex]], which has either four or five. The archicortex, along with the paleocortex and [[periallocortex]], is a subtype of [[allocortex]].<ref name="BrainInfo Paleocortex">{{cite web|title=Paleocortex|url=http://braininfo.rprc.washington.edu/centraldirectory.aspx?type=a&ID=2336|work=BrainInfo|publisher=University of Washington|access-date=5 May 2013}}</ref> Because the number of cortical layers that make up a type of cortical tissue seems to be directly proportional{{clarify|date=February 2024}} to both the information-processing capabilities of that tissue and its [[phylogenetics|phylogenetic age]], the archicortex is thought to be the oldest and most basic type of cortical tissue.<ref name="Purves 2011">{{cite book|author=Purves, Dale|author2=Augustine, George J|author3=Fitzpatrick, David|author4=Hall, William C|author5=LaMantia, Anthony-Samuel|author6=White, Leonard E|title=Neuroscience|year=2011|publisher=Sinauer Associates Inc.|isbn=9780878936465|edition=5th}}</ref>