loading...| Preferred Name |
dorsal plus ventral thalamus |
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| Synonyms |
wider thalamus Th thalamus thalamus opticus thalamencephalon thalami |
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| Definitions |
The thalamus is a paired subcortical brain structure joined at the midline and sitting very near the center of the brain. In the human, each half is roughly the size and shape of a walnut. There are two major components. First is the dorsal thalamus, which is comprised of roughly 15 nuclei with relay cells that project to the cerebral cortex. (By "cortex" in this account, we mean "[neocortex](http://www.knowledge-space.org/wiki/UBERON:0001950).") Second is the ventral thalamus, the major portion of which is the thalamic reticular nucleus, which sits like a shield flush against the lateral surface of the dorsal thalamus; reticular cells are GABAergic and project into the dorsal thalamus to inhibit relay cells. The other cellular component of thalamus, in addition to relay and reticular cells, is interneurons, which are also GABAergic, sit amongst the relay cells, and inhibit them. Generally, the relay cell to interneuron ratio is between 3 and 4 to one. An exception is found the mouse and rat, in which interneurons are essentially missing from all thalamic nuclei except the lateral geniculate nucleus (Arcelli et al, 1997). Most of the relay nuclei topographically innervate the middle layers of cortex, but a few along the midline and extended between other nuclei project rather diffusely to upper cortical layers, including layer 1; rather little is known of these latter, diffusely-projecting nuclei, and they are not further considered in this account (for further details, see Sherman and Guillery, 2006; Jones, 2006). The remaining thalamic relay nuclei each innervates one or a small number of cortical areas. Indeed, all information reaching cortex passes through thalamus, and thus thalamus sits in a strategic position for brain processing. The major role of thalamus is to gate and otherwise modulate the flow of information to cortex. For example, visual information from the retina is not sent directly to visual cortex but instead is relayed through the lateral geniculate nucleus of the thalamus. In the macaque monkey, there are roughly 1x10^6 geniculate relay cells (Williams and Rakic, 1988), but in primary visual cortex there are roughly 1.6x10^8 neurons (O'Kusky and Colonnier, 1982), which is typical of thalamocortical relationships. Thus thalamus represents the final bottleneck of information flow before it gets into cortex. In other words, to modify information flow for processes of attention and other behavioral requirements, it is more efficient to do this at the level of thalamus before it reaches cortex. While there is still much to learn about the cell and circuit properties of thalamus in this role, what we do know supports this general view of thalamic function. For further details of thalamus, see Jones (2006) and Sherman and Guillery (2006). Adapted from [S. Murray Sherman (2006), Scholarpedia, 1(9):1583](http://www.scholarpedia.org/article/Thalamus). Subcortical brain region consisting of paired gray matter bodies in the dorsal diencephalon and forming part of the lateral wall of the third ventricle of the brain. The thalamus represents the major portion of the diencephalon and is commonly divided into cellular aggregates known as nuclear groups.(MeSH). The dorsal topographic division of the interbrain. The macrodissected adult human thalamus was clearly illustrated by Vesalius in 1543 and the term as defined here was introduced by His in 1893. It includes the traditional epithalamus, dorsal thalamus, and ventral thalamus of Herrick (1910, pp. 494, 498). Also see Kuhlenbeck (1927, Ch. 9) and Jones (1985, p. 87). |
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| ID |
http://purl.obolibrary.org/obo/UBERON_0001897 |
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| contributes to morphology of | ||
| database_cross_reference |
MIAA:0000109 galen:Thalamus neuronames:300 VHOG:0000657 PBA:128013014 AAO:0010483 TAO:0001215 BIRNLEX:954 MAT:0000109 EFO:0000910 EMAPA:17540 CALOHA:TS-1031 BTO:0001365 SCTID:244433007 UMLS:C0039729 Wikipedia:Thalamus NCIT:C12459 ZFA:0001215 BAMS:TH BAMS:Th DHBA:10390 DMBA:16376 EV:0100195 GAID:656 HBA:4392 MA:0000179 MBA:549 |
|
| definition |
The thalamus is a paired subcortical brain structure joined at the midline and sitting very near the center of the brain. In the human, each half is roughly the size and shape of a walnut. There are two major components. First is the dorsal thalamus, which is comprised of roughly 15 nuclei with relay cells that project to the cerebral cortex. (By "cortex" in this account, we mean "[neocortex](http://www.knowledge-space.org/wiki/UBERON:0001950).") Second is the ventral thalamus, the major portion of which is the thalamic reticular nucleus, which sits like a shield flush against the lateral surface of the dorsal thalamus; reticular cells are GABAergic and project into the dorsal thalamus to inhibit relay cells. The other cellular component of thalamus, in addition to relay and reticular cells, is interneurons, which are also GABAergic, sit amongst the relay cells, and inhibit them. Generally, the relay cell to interneuron ratio is between 3 and 4 to one. An exception is found the mouse and rat, in which interneurons are essentially missing from all thalamic nuclei except the lateral geniculate nucleus (Arcelli et al, 1997). Most of the relay nuclei topographically innervate the middle layers of cortex, but a few along the midline and extended between other nuclei project rather diffusely to upper cortical layers, including layer 1; rather little is known of these latter, diffusely-projecting nuclei, and they are not further considered in this account (for further details, see Sherman and Guillery, 2006; Jones, 2006). The remaining thalamic relay nuclei each innervates one or a small number of cortical areas. Indeed, all information reaching cortex passes through thalamus, and thus thalamus sits in a strategic position for brain processing. The major role of thalamus is to gate and otherwise modulate the flow of information to cortex. For example, visual information from the retina is not sent directly to visual cortex but instead is relayed through the lateral geniculate nucleus of the thalamus. In the macaque monkey, there are roughly 1x10^6 geniculate relay cells (Williams and Rakic, 1988), but in primary visual cortex there are roughly 1.6x10^8 neurons (O'Kusky and Colonnier, 1982), which is typical of thalamocortical relationships. Thus thalamus represents the final bottleneck of information flow before it gets into cortex. In other words, to modify information flow for processes of attention and other behavioral requirements, it is more efficient to do this at the level of thalamus before it reaches cortex. While there is still much to learn about the cell and circuit properties of thalamus in this role, what we do know supports this general view of thalamic function. For further details of thalamus, see Jones (2006) and Sherman and Guillery (2006). Adapted from [S. Murray Sherman (2006), Scholarpedia, 1(9):1583](http://www.scholarpedia.org/article/Thalamus). |
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| delineatedBy | ||
| depiction |
http://upload.wikimedia.org/wikipedia/commons/c/ce/Brain_chrischan_thalamus.jpg |
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| external_definition |
Part of the diencephalon consisting of a mass of connecting fibers which relay sensory information to the cerebral cortex.[AAO] One of a pair of large oval nervous structures made of gray matter and forming most of the lateral walls of the third ventricle of the brain and part of the diencephalon. [TFD][VHOG] |
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| has exact synonym |
wider thalamus |
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| has_broad_synonym |
Th thalamus |
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| has_obo_namespace |
uberon |
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| has_related_synonym |
thalamus opticus thalamencephalon thalami |
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| has_relational_adjective |
thalamic |
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| homology_notes |
(...) the brain regions of tetrapods, the structures they contain, and their basic organizational features are the same as in fishes.[well established][VHOG] |
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| id |
UBERON:0001897 |
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| in lateral side of | ||
| in_subset |
http://purl.obolibrary.org/obo/uberon/core#human_reference_atlas http://purl.obolibrary.org/obo/uberon/core#efo_slim http://purl.obolibrary.org/obo/uberon/core#vertebrate_core |
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| label |
dorsal plus ventral thalamus |
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| notation |
UBERON:0001897 |
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| part_of | ||
| prefLabel |
dorsal plus ventral thalamus |
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| present_in_taxon | ||
| treeView | ||
| mutually_spatially_disjoint_with | ||
| subClassOf |