Information about Thalamus
| Brain: Thalamus | ||
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| MRI cross-section of human brain, with thalamus marked. | ||
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| Scheme showing the course of the fibers of the lemniscus; medial lemniscus in blue, lateral in red. | ||
| Latin | thalamus dorsalis | |
| subject #189 808 | ||
| NeuroNames | hier-283 | |
| MeSH | Thalamus | |
For the computer game developer, see Thalamus Ltd.
The thalamus (from Greek θάλαμος = bedroom, chamber, IPA= /ˈθæləməs/) is a pair and symmetric part of the brain. It constitutes the main part of the diencephalon.
Location and topography
In the caudal (tail) to oral (mouth) sequence of neuromeres, the diencephalon is located between the mesencephalon (cerebral peduncule, belonging to the brain stem) and the telencephalon. The diencephalon includes also the dorsally located epithalamus (essentially the habenula and annexes) and the perithalamus (prethalamus formerly described as ventral thalamus) containing the zona incerta and the "reticulate nucleus" (not the reticular, term of confusion). Due to their different ontogenetic origins, the epithalamus and the perithalamus are formally distinguished from the thalamus proper.Phylogenetic modifications are such that this article essentially deals with the human thalamus and may differ in comparison with accounts in non-upper primate species. In normal humans, the two thalami are prominent bulb-shaped masses, about 5.7 cm in length, located obliquely (about 30°) and symmetrically on each side of the third ventricle. The two can adhere on a variable extent in 30% of humans. This adhesio interthalamica (interthalamic adhesion, or massa intermedia) does not contain interthalamic neural connection in our species.
Anatomy
The thalamus comprises a system of lamellae (made up of myelinated fibers) separating different thalamic subparts. Other areas are defined by distinct clusters of neurons, such as the periventricular gray, the intralaminar elements, the "nucleus limitans", and others. These latter structures, different in structure from the major part of the thalamus, have been grouped together into the allothalamus as opposed to the isothalamus (Percheron, 2003).[1] This distinction simplifies the global description of the thalamus.Please see also List of thalamic nuclei.
Arterial supply
The thalamus derives its blood supply from a number of arteries including polar and paramedian arteries, inferolateral (thalamogeniculate) arteries, and posterior (medial and lateral) choroidal arteries.[2] These are all branches of the posterior cerebral artery.Function
The thalamus is known to have multiple functions. Deduced from the design of the isothalamus, it is generally believed to act as a translator for which various "prethalamic" inputs are processed into a form readable by the cortex. The thalamus is believed to relay information selectively to various parts of the cortex, as one thalamic point may reach one or several regions in the cortex.The thalamus also plays an important role in regulating states of sleep and wakefulness. Thalamic nuclei have strong reciprocal connections with the cerebral cortex, forming thalamo-cortico-thalamic circuits that are believed to be involved with consciousness. The thalamus plays a major role in regulating arousal, the level of awareness and activity. Damage to the thalamus can lead to permanent coma.
Many different functions are linked to the system to which thalamic parts belong. This is at first the case for sensory systems (which excepts the olfactory function) auditory, somatic, visceral, gustatory and visual systems where localised lesions provoke particular sensory deficits. A major role of the thalamus is devoted to "motor" systems. This has been and continues to be a subject of interest for investigators. VIm, the relay of cerebellar afferences, is the target of stereotactians particularly for the improvement of tremor. The role of the thalamus in the more anterior pallidal and nigral territories in the basal ganglia system disturbances is recognized but still poorly known. The contribution of the thalamus to vestibular or to tectal functions is almost ignored. The thalamus has been thought of as a "relay" that simply forwards signals to the cerebral cortex. Newer research suggests that thalamic function is more complicated.[3]
Pathology
Cerebrovascular accidents (strokes) can cause thalamic syndrome (Dejerine and Roussy, 1906),[4] which results in a contralateral hemianaesthesia, burning or aching sensation on one half of a body (painful anaesthesia), often accompanied by mood swings. Ischaemia of the territory of the paramedian artery, if bilateral, causes serious troubles including akinetic mutism accompanied or not by oculomotor troubles.Korsakoff's Syndrome, stems from mammillary bodies, mammilothalamic, or thalamic lesions.
Development
The thalamic complex is composed of the perithalamus (or prethalamus, previously also known as ventral thalamus), the zona limitans intrathalamica (ZLI) and the thalamus (dorsal thalamus).[5][6]The ZLI is a transverse boundary located between the perithalamus and the functional distinct thalamus. Besides its morphological characteristics, it bears the hallmarks of a signalling centre. Fate mapping experiments in chicks have shown that the ZLI is cell lineage restricted at its boundaries and therefore can be termed a true developmental compartment in the forebrain.[7]
Besides morphological characteristics, the ZLI is the only structure in the alar plate of the neural tube that expresses signaling molecules.[8]
In mice, the function of Shh (Sonic Hedgehog) signaling at the ZLI has not been addressed directly due to a complete absence of the diencephalon in Shh mutants.[9]
Studies in chicks have shown that Shh is both necessary and sufficient for thalamic gene induction.[10]
In zebrafish, it was shown that the expression of two Shh genes, shh-a and shh-b (formerly described as twhh) mark the ZLI territory, and that Shh signaling is sufficient for the molecular differentiation of both the prethalamus and the thalamus but is not required for their maintenance and Shh signaling from the ZLI/alar plate is sufficient for the maturation of prethalamic and thalamic territory while ventral Shh signals are dispensable.[11]
References
1. ^ Percheron, G. (2003) "Thalamus". In Paxinos, G. and May, J.(eds). The human nervous system. 2d Ed. Elsevier. Amsterdam. pp.592-675
2. ^ Percheron, G. (1982) The arterial supply of the thalamus. In Schaltenbrand and Walker, A.E.(eds) Stereotaxy of the human brain. Thieme . Stuttgart. pp.218-232
3. ^ [1]
4. ^ Dejerine, J. and Roussy. G.(1906) Le syndrome thalamique. Rev. Neurol. 14: 521-532
5. ^ Kuhlenbeck, H. (1937). The ontogenetic development of diencephalic centres in the bird's brain (chick) and comparison with the reptilian and mammalian diencephalon. J. Comp. Neurol. 66
6. ^ Shimamura, K., Hartigan, D. J., Martinez, S., Puelles, L. and Rubenstein, J. L. (1995). Longitudinal organization of the anterior neural plate and neural tube. Development 121,3923 -3933.
7. ^ Zeltser, L. M., Larsen, C. W. and Lumsden, A. (2001). A new developmental compartment in the forebrain regulated by Lunatic fringe. Nat. Neurosci. 4, 683-684.
8. ^ Puelles, L. and Rubenstein, J. L. (2003). Forebrain gene expression domains and the evolving prosomeric model. Trends Neurosci. 26,469 -476.
9. ^ Ishibashi, M. and McMahon, A. P. (2002). A sonic hedgehog-dependent signalling relay regulates growth of diencephalic and mesencephalic primordia in the early mouse embryo. Development 129,4807 -4819.
10. ^ Kiecker, C. and Lumsden, A. (2004). Hedgehog signalling from the ZLI regulates diencephalic regional identity. Nat. Neurosci. 7,1242 -1249.
11. ^ Scholpp S, Wolf O, Brand M, Lumsden A. Hedgehog signalling from the zona limitans intrathalamica orchestrates patterning of the zebrafish diencephalon'. Development. 2006 Mar;133(5):855-64[2]
2. ^ Percheron, G. (1982) The arterial supply of the thalamus. In Schaltenbrand and Walker, A.E.(eds) Stereotaxy of the human brain. Thieme . Stuttgart. pp.218-232
3. ^ [1]
4. ^ Dejerine, J. and Roussy. G.(1906) Le syndrome thalamique. Rev. Neurol. 14: 521-532
5. ^ Kuhlenbeck, H. (1937). The ontogenetic development of diencephalic centres in the bird's brain (chick) and comparison with the reptilian and mammalian diencephalon. J. Comp. Neurol. 66
6. ^ Shimamura, K., Hartigan, D. J., Martinez, S., Puelles, L. and Rubenstein, J. L. (1995). Longitudinal organization of the anterior neural plate and neural tube. Development 121,3923 -3933.
7. ^ Zeltser, L. M., Larsen, C. W. and Lumsden, A. (2001). A new developmental compartment in the forebrain regulated by Lunatic fringe. Nat. Neurosci. 4, 683-684.
8. ^ Puelles, L. and Rubenstein, J. L. (2003). Forebrain gene expression domains and the evolving prosomeric model. Trends Neurosci. 26,469 -476.
9. ^ Ishibashi, M. and McMahon, A. P. (2002). A sonic hedgehog-dependent signalling relay regulates growth of diencephalic and mesencephalic primordia in the early mouse embryo. Development 129,4807 -4819.
10. ^ Kiecker, C. and Lumsden, A. (2004). Hedgehog signalling from the ZLI regulates diencephalic regional identity. Nat. Neurosci. 7,1242 -1249.
11. ^ Scholpp S, Wolf O, Brand M, Lumsden A. Hedgehog signalling from the zona limitans intrathalamica orchestrates patterning of the zebrafish diencephalon'. Development. 2006 Mar;133(5):855-64[2]
See also
- Primate basal ganglia system
- Regions in the human thalamus
- Thalamus (non primate)
- List of thalamic nuclei
Additional images
Schematic representation of the chief ganglionic categories (I to V). | Deep dissection of brain-stem. Lateral view. | Deep dissection of brain-stem. Ventral view. | Mesal aspect of a brain sectioned in the median sagittal plane. |
Dissection showing the ventricles of the brain. | Coronal section of brain immediately in front of pons. | Coronal section of brain through intermediate mass of third ventricle. | Coronal section of lateral and third ventricles. |
) Section of brain showing upper surface of temporal lobe. | ) Horizontal section of right cerebral hemisphere. | The left optic nerve and the optic tracts. | ) Parts of the thalamus |
) Projections of the thalamus | ) Parts of the thalamus | ) Thalamus |
External links
Magnetic resonance imaging (MRI), formerly referred to as magnetic resonance tomography (MRT) and, in scientific circles and as originally marketed by companies such as General Electric, nuclear magnetic resonance imaging (NMRI) or NMR zeugmatography imaging
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A lemniscus (Greek for ribbon[1]) can refer to:
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- In mathematics, a lemniscate
- In anatomy, a part of the brain, such as the medial lemniscus or lateral lemniscus
References
1.
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The medial lemniscus, also known as Reil's band or Reil's ribbon, is a pathway in the brainstem that carries sensory information from the gracile and cuneate nuclei to the thalamus.
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The lateral lemniscus is a tract of axons in the brainstem that carries information about sound from the cochlear nucleus to various brainstem nuclei and ultimately the contralateral inferior colliculus of the midbrain.
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Latin}}}
Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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NeuroNames is a system of nomenclature for the human and/or macaque brain.
It is maintained by the University of Washington and is a part of a tool called "BrainInfo". BrainInfo helps one identify structures in the brain.
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It is maintained by the University of Washington and is a part of a tool called "BrainInfo". BrainInfo helps one identify structures in the brain.
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Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
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Thalamus Ltd (also known as Thalamus) was a British computer game developer that published titles for a number of 8-bit and 16-bit platforms during the late 1980s and early 1990s.
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Official language of: Greece
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Writing system: Greek alphabet
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Official language of: Greece
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recognised as minority language in parts of:
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The diencephalon is the region of the brain that includes the thalamus, hypothalamus, epithalamus, prethalamus or subthalamus and pretectum. It is derived from the prosencephalon. The diencephalon is located at the midline of the brain, above the mesencephalon of the brain stem.
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Neuromeres are transient segments during the early development of the human brain. Around the fifth week of biological development, there are 15 visible neuromeres.
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In biological anatomy, the mesencephalon (or midbrain) is the middle of three vesicles that arise from the neural tube that forms the brain of developing animals. Caudally the mesencephalon adjoins the pons (metencephalon) and rostrally it adjoins the diencephalon
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The cerebral peduncle, by most classifications, is everything in the mesencephalon except the tectum. The region includes the midbrain tegmentum, crus cerebri, substantia nigra and pretectum. The peduncles are also known as the crus cerebri.
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The brain stem is the lower part of the brain, adjoining and structurally continuous with the spinal cord. Most sources consider the pons, medulla oblongata, and midbrain all to be part of the brainstem.
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The diencephalon is the region of the brain that includes the thalamus, hypothalamus, epithalamus, prethalamus or subthalamus and pretectum. It is derived from the prosencephalon. The diencephalon is located at the midline of the brain, above the mesencephalon of the brain stem.
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The epithalamus is a dorsal posterior segment of the diencephalon (a segment in the middle of the brain also containing the hypothalamus and the thalamus) which includes the habenula, the stria medullaris and the pineal body.
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The prethalamus (formerly described as ventral thalamus) or subthalamus is part of the diencephalon and therefore part of the brain.
Developmental biologist prefer the term prethalamus, as it can be genetically defined (Puelles and Rubenstein, 2003), whereas (human)
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Developmental biologist prefer the term prethalamus, as it can be genetically defined (Puelles and Rubenstein, 2003), whereas (human)
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The zona incerta is a small region of gray matter that is part of the subthalamus.
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Anatomy
This nucleus is located medially to the internal capsule, ventral to the thalamus, and is contiguous with the Thalamic reticular nucleus...... Click the link for more information.
Ontogeny (also ontogenesis or morphogenesis) describes the origin and the development of an organism from the fertilized egg to its mature form. Ontogeny is studied in developmental biology.
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Interthalamic adhesion (massa intermedia, middle commissure, gray commissure).
In non-human mammals it is a large structure. In humans this mass averages about 1 cm.
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In non-human mammals it is a large structure. In humans this mass averages about 1 cm.
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Myelin is an electrically insulating phospholipid layer that surrounds the axons of many neurons. It is an outgrowth of glial cells: Schwann cells supply the myelin for peripheral neurons while oligodendrocytes supply it to those of the central nervous system.
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axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body or soma.
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Anatomy
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Neurons (also known as neurones and nerve cells) are electrically excitable cells in the nervous system that process and transmit information. In vertebrate animals, neurons are the core components of the brain, spinal cord and peripheral nerves.
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The Allothalamus is a division used by some researchers in describing the thalamus.[1].
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Paramedian formation
This or periventricular formation lies along the wall of the third ventricle...... Click the link for more information.
The isothalamus is a division used by some researchers in describing the thalamus.[1].
The isothalamus constitutes 90% or more of the thalamus, and despite the variety of functions it serves, follows a simple organizational scheme.
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The isothalamus constitutes 90% or more of the thalamus, and despite the variety of functions it serves, follows a simple organizational scheme.
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Nuclear groups of the thalamus include:
This traditional list does not fit in several places with human thalamic anatomy
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This traditional list does not fit in several places with human thalamic anatomy
- anterior nuclear group
- anteroventral nucleus
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In human anatomy, the posterior cerebral artery is the blood vessel that supplies oxygenated blood to the posterior aspect of the brain (occipital lobe). It arises from the basilar artery and connects with the ipsilateral middle cerebral artery and internal carotid artery via the
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Sleep is the state of natural rest observed throughout the animal kingdom, in all mammals and birds, and in many reptiles, amphibians, and fish.
In humans, other mammals, and many other animals that have been studied — such as fish, birds, ants, and fruit-flies —
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In humans, other mammals, and many other animals that have been studied — such as fish, birds, ants, and fruit-flies —
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Consciousness is a characteristic of the mind generally regarded to comprise qualities such as subjectivity, self-awareness, sentience, sapience, and the ability to perceive the relationship between oneself and one's environment.
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Coma
Classifications and external resources
ICD-10 R 40.2
ICD-9 780.01
In medicine, a coma (from the Greek κῶμα koma, meaning deep sleep) is a profound state of unconsciousness.
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Classifications and external resources
ICD-10 R 40.2
ICD-9 780.01
In medicine, a coma (from the Greek κῶμα koma, meaning deep sleep) is a profound state of unconsciousness.
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