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In anatomy of animals, the archipallium or archicortex is the phylogenetically the oldest region of the brain's pallium or cortex.

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Archicortex in human 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
Part ofcerebral cortex or pallium
SystemOlfactory system
NeuroLex IDbirnlex_715
TEE5., E5.
Anatomical terms of neuroanatomy

The archipallium or archicortex is often considered contiguous with the olfactory cortex, but the extent of the archipallium varies among species. In older species, such as fish, the archipallium makes up most of the cerebrum. Amphibians develop an archipallium and paleopallium, whereas reptiles develop an archipallium, paleopallium and a primitive neopallium.

In humans, the archipallium makes up the hippocampus.

Archicortex is also defined as a type of cortical tissue that consists of three cortical laminae (layers of neuronal cell bodies).[1] It has fewer laminae than both neocortex, which has six, and paleocortex, which has either four or five. Archicortex, along with paleocortex and periallocortex, is a type of allocortex.[2] Because the number of laminae that compose a type of cortical tissue seems to be directly proportional to both the information-processing capabilities of that tissue and its phylogenetic age, archicortex is thought to be the oldest and most basic type of cortical tissue.[1]


Archicortex is most prevalent in the olfactory cortex and the hippocampus,[3] which are responsible for processing smells and forming memories, respectively.[4] Because olfaction is considered to be the phylogenetically oldest sensory modality,[5] and the limbic system, of which the hippocampus is a part, is one of the oldest systems in the brain,[6] it is likely that archicortex was one of the first types of tissue to develop in primitive nervous systems.

Archicortical precursor cells are also present in the dentate gyrus of the developing mammalian embryo.[7]

See alsoEdit


  1. ^ a b Purves, Dale; Augustine, George J; Fitzpatrick, David; Hall, William C; LaMantia, Anthony-Samuel; White, Leonard E (2011). Neuroscience (5th ed.). Sinauer Associates Inc. ISBN 9780878936465.
  2. ^ "Paleocortex". BrainInfo. University of Washington. Retrieved 5 May 2013.
  3. ^ Wills, Tom J.; Cacucci, Francesca; Burgess, Neil; O'Keefe, John (18 June 2010). "Development of the Hippocampal Cognitive Map in Preweanling Rats". Science. 328 (5985): 1573–1576. doi:10.1126/science.1188224. PMC 3543985. PMID 20558720.
  4. ^ Haberly, Lewis B (1990). "Comparative Aspects of Olfactory Cortex". Cerebral Cortex (8B ed.). pp. 137–166. ISBN 978-1-4615-3824-0.
  5. ^ Albrecht, J.; Wiesmann, M. (August 2006). "Das olfaktorische System des Menschen". Der Nervenarzt. 77 (8): 931–939. doi:10.1007/s00115-006-2121-z.
  6. ^ Rajmohan, V.; Mohandas, E. (April–June 2007). "The limbic system". Indian Journal of Psychiatry. 49 (2): 132–139. doi:10.4103/0019-5545.33264.
  7. ^ Pellegrini, M.; Mansouri, A.; Simeone, A.; Boncinelli, E.; Gruss, P. (December 1996). "Dentate gyrus formation requires Emx2". Development. 122 (12): 3893–3898. PMID 9012509.