Thearchicortex,orarchipallium,is thephylogeneticallysecond oldest region of thebrain'scerebral cortex(the oldest is thepaleocortex). In older species, such as fish, the archipallium makes up most of thecerebrum.Amphibiansdevelop an archipallium andpaleopallium.
| Archicortex | |
|---|---|
 The archicortex in humans is a synonym of thehippocampal formation.The hippocampal formation is shown here, as drawn bySantiago Ramon y Cajal:DG: dentate gyrus. Sub: subiculum. EC: entorhinal cortex. CA1-CA3: hippocampus proper | |
| Details | |
| Part of | cerebral cortexorpallium |
| System | Olfactory system |
| Identifiers | |
| Latin | archicortex |
| NeuroNames | 170 |
| NeuroLexID | birnlex_715 |
| TA98 | A14.1.09.302 |
| TA2 | 5530 |
| TE | E5.14.3.4.3.1.31 E5.14.3.4.3.1.32, E5.14.3.4.3.1.31 |
| FMA | 62424 |
| Anatomical terms of neuroanatomy | |
In humans, the archicortex makes up the threecortical layersof thehippocampus.[1]It has fewercortical layersthan both theneocortex,which has six, and thepaleocortex,which has either four or five. The archicortex, along with the paleocortex andperiallocortex,is a subtype ofallocortex.[2]Because the number of cortical layers that make up a type of cortical tissue seems to be directly proportional[clarification needed]to both the information-processing capabilities of that tissue and itsphylogenetic age,the archicortex is thought to be the oldest and most basic type of cortical tissue.[3]
Location
editThe archicortex is most prevalent in theolfactory cortexand thehippocampus,[4]which are responsible for processing smells and forming memories, respectively.[5]Because olfaction is considered to be the phylogenetically oldest sensory modality,[6]and thelimbic system,of which the hippocampus is a part, is one of the oldest systems in the brain,[7]it is likely that the archicortex was one of the first types of tissue to develop in primitivenervous systems.[7]
Archicortical precursor cells are also present in thedentate gyrusof the developingmammalianembryo.[8]
Structure
editThe archicortex is largely made up of memorizing cells with two types of afferent synapses: excitatory and unmodifiable inhibitory synapses.[9]Memorizing cell inhibition serves two functions: one is controlling synaptic modification conditions in the memorizing cell dendrites during learning, and the other is controlling cell thresholds during recall.[9]The archicortex may also containcodoncells.[9]Unlike theneocortex,the archicortex lacks climbing fibers (fibers involved in the clustering part of neocortical classification).[9]Consequently, the archicortex is not adapted for this type of classification.[9]
Memory
editUnlike the neocortex, current theories of the archicortex argue that it performs simple memorization without changing the input's format in any complex manner.[9]The archicortex is unable to classify inputs. It has two main uses: free simple memory and directed simple memory.[9]
See also
editReferences
edit- ^Purves, Dale (2012).Neuroscience(5th ed.). Sunderland, Mass. p. 731.ISBN9780878936953.
{{cite book}}:CS1 maint: location missing publisher (link) - ^"Paleocortex".BrainInfo.University of Washington.Retrieved5 May2013.
- ^Purves, Dale; Augustine, George J; Fitzpatrick, David; Hall, William C; LaMantia, Anthony-Samuel; White, Leonard E (2011).Neuroscience(5th ed.). Sinauer Associates Inc.ISBN9780878936465.
- ^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.Bibcode:2010Sci...328.1573W.doi:10.1126/science.1188224.PMC3543985.PMID20558720.
- ^Haberly, Lewis B (1990). "Comparative Aspects of Olfactory Cortex".Cerebral Cortex(8B ed.). Springer. pp.137–166.ISBN978-1-4615-3824-0.
- ^Albrecht, J.; Wiesmann, M. (August 2006). "Das olfaktorische System des Menschen".Der Nervenarzt.77(8):931–939.doi:10.1007/s00115-006-2121-z.PMID16871378.
- ^abRajmohan, V.; Mohandas, E. (April–June 2007)."The limbic system".Indian Journal of Psychiatry.49(2):132–139.doi:10.4103/0019-5545.33264.PMC2917081.PMID20711399.
- ^Pellegrini, M.; Mansouri, A.; Simeone, A.; Boncinelli, E.; Gruss, P. (December 1996). "Dentate gyrus formation requires Emx2".Development.122(12):3893–3898.doi:10.1242/dev.122.12.3893.hdl:11858/00-001M-0000-0013-00C2-8.PMID9012509.
- ^abcdefgMarr, D.; Brindley, Giles Skey (1971-07-01). "Simple memory: a theory for archicortex".Philosophical Transactions of the Royal Society B: Biological Sciences.262(841):23–81.Bibcode:1971RSPTB.262...23M.doi:10.1098/rstb.1971.0078.PMID4399412.
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