出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/11/25 10:02:38」(JST)[Wiki en表示]
|thalamus marked (MRI cross-section)|
|Gray's||subject #189 808|
|Components||See List of thalamic nuclei|
|Artery||Posterior cerebral artery and branches|
The thalamus (from Greek θάλαμος, "inner chamber") is a midline symmetrical structure within the brains of vertebrates including humans, situated between the cerebral cortex and midbrain. Its function includes relaying sensory and motor signals to the cerebral cortex, along with the regulation of consciousness, sleep, and alertness. The thalamus surrounds the third ventricle. It is the main product of the embryonic diencephalon.
The thalamus is perched on top of the brainstem, near the center of the brain, with nerve fibers projecting out to the cerebral cortex in all directions. The medial surface of the thalamus constitutes the upper part of the lateral wall of the third ventricle, and is connected to the corresponding surface of the opposite thalamus by a flattened gray band, the Interthalamic adhesion.
Both parts of this structure of the brain in the human are each about the size and shape of a walnut. These are about three centimetres in length, at the widest part 2.5 centimetres across and about 2 centimetres in height (the nut relative to an unshelled nut with the nut-shell join in the horizontal plane).
The two halves of the thalamus 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 thalamus derives its blood supply from four arteries including the polar artery (posterior communicating artery), paramedian thalamic-subthalamic arteries, inferolateral (thalamogeniculate) arteries, and posterior (medial and lateral) choroidal arteries. These are all derived from the vertebrobasilar arterial system except the polar artery.
Some people have the artery of Percheron, which is a rare anatomic variation in which a single arterial trunk arises from the posterior cerebral artery to supply both thalami.
The thalamus is part of a nuclear complex structured of four parts, the hypothalamus, epithalamus, ventral thalamus, and dorsal thalamus.
Derivatives of the diencephalon also include 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.
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. This distinction simplifies the global description of the thalamus.
The thalamus is manifoldly connected to the hippocampus via the mammillo-thalamic tract, this tract comprises the mammilary body and fornix.
The spinothalamic tract is a sensory pathway originating in the spinal cord. It transmits information to the thalamus about pain, temperature, itch and crude touch. There are two main parts: the lateral spinothalamic tract, which transmits pain and temperature, and the anterior (or ventral) spinothalamic tract, which transmits crude touch and pressure.
The thalamus has multiple functions. It may be thought of as a kind of switchboard of information. It is generally believed to act as a relay between a variety of subcortical areas and the cerebral cortex. In particular, every sensory system (with the exception of the olfactory system) includes a thalamic nucleus that receives sensory signals and sends them to the associated primary cortical area. For the visual system, for example, inputs from the retina are sent to the lateral geniculate nucleus of the thalamus, which in turn projects to the primary visual cortex (area V1) in the occipital lobe. The thalamus is believed to both process sensory information as well as relay it—each of the primary sensory relay areas receives strong "back projections" from the cerebral cortex. Similarly the medial geniculate nucleus acts as a key auditory relay between the inferior colliculus of the midbrain and the primary auditory cortex, and the ventral posterior nucleus is a key somatosensory relay, which sends touch and proprioceptive information to the primary somatosensory 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.
The role of the thalamus in the more anterior pallidal and nigral territories in the basal ganglia system disturbances is recognized but still poorly understood. 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 selective. Many different functions are linked to various regions of the thalamus. This is the case for many of the sensory systems (except for the olfactory system), such as the auditory, somatic, visceral, gustatory and visual systems where localized lesions provoke specific sensory deficits. A major role of the thalamus is devoted to "motor" systems. The thalamus is functionally connected to the hippocampus as part of the extended hippocampal system at the thalamic anterior nuclei with respect to spatial memory and spatial sensory datum they are crucial for human episodic memory and rodent event memory. There is support for the hypothesis that thalamic regions connection to particular parts of the mesio-temporal lobe provide differentiation of the functioning of recollective and familiarity memory.
The neuronal information processes necessary for motor control were proposed as a network involving the thalamus as a subcortical motor centre. Through investigations of the anatomy of the brains of primates the nature of the interconnected tissues of the cerebellum to the multiple motor cortices suggested that the thalamus fulfills a key function in providing the specific channels from the basal ganglia and cerebellum to the cortical motor areas. In an investigation of the saccade and antisaccade motor response in three monkeys, the thalamic regions were found to be involved in the generation of antisaccade eye-movement.
Human brain frontal (coronal) section
The thalamic complex is composed of the perithalamus (or prethalamus, previously also known as ventral thalamus), the mid-diencephalic organiser (which forms later the zona limitans intrathalamica (ZLI) ) and the thalamus (dorsal thalamus). The development of the thalamus can be subdivide into three steps The thalamus is the largest structure deriving from the embryonic diencephalon, the posterior part of the forebrain situated between the midbrain and the cerebrum.
Early brain development
After neurulation the anlage of the prethalamus and the thalamus is induced within the neural tube. Data from different vertebrate model organisms support a model in which the interaction between two transcription factors, Fez and Otx, are of decisive importance. Fez is expressed in the prethalamus, and functional experiments show that Fez is required for prethalamus formation. Posteriorly, Otx1 and Otx2 abut the expression domain of Fez and are required for proper development of the thalamus.
The formation of the mid-diencephalic organiser (MDO)
At the interface between the expression domains of Fez and Otx, the mid-diencephalic organizer (MDO, also called the ZLI organiser) is induced within the thalamic anlage. The MDO is the central signalling organizer in the thalamus. A lack of the organizer leads to the absence of the thalamus. The MDO matures from ventral to dorsal during development. Members of the SHH family and of the Wnt family are the main principal signals emitted by the MDO.
Besides its importance as signalling center, the organizer matures into the morphological structure of the zona limitans intrathalamica (ZLI).
Maturation and parcellation of the thalamus
After its induction, the MDO starts to orchestrate the development of the thalamic anlage by release of signalling molecules such as Shh. In mice, the function of signaling at the MDO has not been addressed directly due to a complete absence of the diencephalon in Shh mutants.
Studies in chicks have shown that Shh is both necessary and sufficient for thalamic gene induction. In zebrafish, it was shown that the expression of two Shh genes, shh-a and shh-b (formerly described as twhh) mark the MDO 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 MDO/alar plate is sufficient for the maturation of prethalamic and thalamic territory while ventral Shh signals are dispensable.
The exposure to Shh leads to differentiation of thalamic neurons. SHH signaling from the MDO induces a posterior-to-anterior wave of expression the proneural gene Neurogenin1 in the major (caudal) part of the thalamus, and Ascl1 (formerly Mash1) in the remaining narrow stripe of rostral thalamic cells immediately adjacent to the MDO, and in the prethalamus.
This zonation of proneural gene expression leads to the differentiation of glutamatergic relay neurons from the Neurogenin1+ precursors and of GABAergic inhibitory neurons from the Ascl1+ precursors. In fish, selection of these alternative neurotransmitter fates is controlled by the dynamic expression of Her6 the homolog of HES1. Expression of this hairy-like bHLH transcription factor, which represses Neurogenin but is required for Ascl1, is progressively lost from the caudal thalamus but maintained in the prethalamus and in the stripe of rostral thalamic cells. In addition, studies on chick and mice have shown that blocking the Shh pathway leads to absence of the rostral thalamus and substantial decrease of the caudal thalamus. The rostral thalamus will give rise to the reticular nucleus mainly whereby the caudal thalamus will form the relay thalamus and will be further subdivided in the thalamic nuclei.
In humans, a common genetic variation in the promotor region of the serotonin transporter (the SERT-long and -short allele: 5-HTTLPR) has been shown to affect the development of several regions of the thalamus in adults. People who inherit two short alleles (SERT-ss) have more neurons and a larger volume in the pulvinar and possibly the limbic regions of the thalamus. Enlargement of the thalamus provides an anatomical basis for why people who inherit two SERT-ss alleles are more vulnerable to major depression, posttraumatic stress disorder, and suicide.
A cerebrovascular accident (stroke) can lead to the thalamic syndrome, which involves a one-sided burning or aching sensation often accompanied by mood swings. Bilateral ischemia of the area supplied by the paramedian artery can cause serious problems including akinetic mutism, and be accompanied by oculomotor problems. A related concept is thalamocortical dysrhythmia. The occlusion of the artery of Percheron can lead to a bilateral thalamus infarction.
Korsakoff's syndrome stems from damage to the mammillary body, the mammillothalamic fasciculus or the thalamus.
Fatal familial insomnia is a hereditary prion disease in which degeneration of the thalamus occurs, causing the patient to gradually lose his ability to sleep and progressing to a state of total insomnia, which invariably leads to death.
- Primate basal ganglia system
- List of regions in the human brain
- Thalamus (non primate)
- List of thalamic nuclei
- Thalamic stimulator
|This section looks like an image gallery. Wikipedia policy discourages galleries of random images of the article subject; please improve or remove the section accordingly, moving freely licensed images to Wikimedia Commons if not already hosted there. (February 2012)|
Images are circa 1858.
The left optic nerve and the optic tracts.
Coronal section of lateral and third ventricles.
Dissection showing the ventricles of the brain.
Section of brain showing upper surface of temporal lobe.
Horizontal section of right cerebral hemisphere.
Mesal aspect of a brain sectioned in the median sagittal plane.
Schematic representation of the chief ganglionic categories (I to V).
Scheme showing the course of the fibers of the lemniscus; medial lemniscus in blue, lateral in red.
Deep dissection of brain-stem. Lateral view.
Deep dissection of brain-stem. Ventral view.
Coronal section of brain immediately in front of pons.
Coronal section of brain through intermediate mass of third ventricle.
- Harper - index & University of Washington Faculty Web Server & Search engine search page + Perseus Project tufts.edu Retrieved 2012-02-09
- Sherman, S. (2006). "Thalamus". Scholarpedia 1 (9): 1583. doi:10.4249/scholarpedia.1583.
- S. M. Sherman & Ray Guillery -ISBN 0-12-305460-5 → Elsevier B.V [Retrieved 2012-02-10][page needed]
- Percheron, G. (1982). "The arterial supply of the thalamus". In Schaltenbrand; Walker, A. E.. Stereotaxy of the human brain. Stuttgart: Thieme. pp. 218–32.
- Herrero, María-Trinidad; Barcia, Carlos; Navarro, Juana (2002). "Functional anatomy of thalamus and basal ganglia". Child's Nervous System 18 (8): 386. doi:10.1007/s00381-002-0604-1.
- Jones Edward G.(2007) "The Thalamus" Cambridge Uni. Press[page needed]
- Percheron, G. (2003). "Thalamus". In Paxinos, G.; May, J.. The human nervous system (2nd ed.). Amsterdam: Elsevier. pp. 592–675.
- Carlesimo, GA; Lombardi, MG; Caltagirone, C (2011). "Vascular thalamic amnesia: A reappraisal". Neuropsychologia 49 (5): 777–89. doi:10.1016/j.neuropsychologia.2011.01.026. PMID 21255590.
- Steriade, Mircea; Llinás, Rodolfo R. (1988). "The Functional States of the Thalamus and the Associated Neuronal Interplay". Physiological Reviews 68 (3): 649–742. PMID 2839857. http://physrev.physiology.org/content/68/3/649.extract.
- Leonard, Abigail W. (August 17, 2006). "Your Brain Boots Up Like a Computer". LiveScience. http://www.livescience.com/980-brain-boots-computer.html.
- Stein, Thor; Moritz, Chad; Quigley, Michelle; Cordes, Dietmar; Haughton, Victor; Meyerand, Elizabeth (2000). "Functional Connectivity in the Thalamus and Hippocampus Studied with Functional MR Imaging". American Journal of Neuroradiology 21 (8): 1397–401. PMID 11003270. http://www.ajnr.org/cgi/pmidlookup?view=long&pmid=11003270.
- Aggleton, John P.; Brown, Malcolm W. (1999). "Episodic memory, amnesia, and the hippocampal–anterior thalamic axis". Behavioral and Brain Sciences 22 (3): 425–44; discussion 444–89. doi:10.1017/S0140525X99002034. PMID 11301518.
- Aggleton, John P.; O'Mara, Shane M.; Vann, Seralynne D.; Wright, Nick F.; Tsanov, Marian; Erichsen, Jonathan T. (2010). "Hippocampal-anterior thalamic pathways for memory: Uncovering a network of direct and indirect actions". European Journal of Neuroscience 31 (12): 2292–307. doi:10.1111/j.1460-9568.2010.07251.x. PMC 2936113. PMID 20550571. //www.ncbi.nlm.nih.gov/pmc/articles/PMC2936113/.
- Burgess, Neil; Maguire, Eleanor A; O'Keefe, John (2002). "The Human Hippocampus and Spatial and Episodic Memory". Neuron 35 (4): 625–41. doi:10.1016/S0896-6273(02)00830-9. PMID 12194864.
- Evarts, E V; Thach, W T (1969). "Motor Mechanisms of the CNS: Cerebrocerebellar Interrelations". Annual Review of Physiology 31: 451–98. doi:10.1146/annurev.ph.31.030169.002315. PMID 4885774.
- Orioli, PJ; Strick, PL (1989). "Cerebellar connections with the motor cortex and the arcuate premotor area: An analysis employing retrograde transneuronal transport of WGA-HRP". The Journal of comparative neurology 288 (4): 612–26. doi:10.1002/cne.902880408. PMID 2478593.
- Asanuma et al. 1983; et al[verification needed]
- Kurata, K (2005). "Activity properties and location of neurons in the motor thalamus that project to the cortical motor areas in monkeys". Journal of neurophysiology 94 (1): 550–66. doi:10.1152/jn.01034.2004. PMID 15703228.
- http://www.optomotorik.de/blicken/anti-rev.htm[full citation needed]
- Kunimatsu, J; Tanaka, M (2010). "Roles of the primate motor thalamus in the generation of antisaccades". The Journal of neuroscience 30 (14): 5108–17. doi:10.1523/JNEUROSCI.0406-10.2010. PMID 20371831.
- Kuhlenbeck, Hartwig (1937). "The ontogenetic development of the diencephalic centers in a bird's brain (chick) and comparison with the reptilian and mammalian diencephalon". The Journal of Comparative Neurology 66: 23. doi:10.1002/cne.900660103.
- Shimamura, K; Hartigan, DJ; Martinez, S; Puelles, L; Rubenstein, JL (1995). "Longitudinal organization of the anterior neural plate and neural tube". Development 121 (12): 3923–33. PMID 8575293.
- Scholpp, Steffen; Lumsden, Andrew (2010). "Building a bridal chamber: Development of the thalamus". Trends in Neurosciences 33 (8): 373–80. doi:10.1016/j.tins.2010.05.003. PMC 2954313. PMID 20541814. //www.ncbi.nlm.nih.gov/pmc/articles/PMC2954313/.
- Hirata, T.; Nakazawa, M; Muraoka, O; Nakayama, R; Suda, Y; Hibi, M (2006). "Zinc-finger genes Fez and Fez-like function in the establishment of diencephalon subdivisions". Development 133 (20): 3993–4004. doi:10.1242/dev.02585. PMID 16971467.
- Jeong, J.-Y.; Einhorn, Z.; Mathur, P.; Chen, L.; Lee, S.; Kawakami, K.; Guo, S. (2007). "Patterning the zebrafish diencephalon by the conserved zinc-finger protein Fezl". Development 134 (1): 127–36. doi:10.1242/dev.02705. PMID 17164418.
- Acampora, D; Avantaggiato, V; Tuorto, F; Simeone, A (1997). "Genetic control of brain morphogenesis through Otx gene dosage requirement". Development 124 (18): 3639–50. PMID 9342056.
- Scholpp, S.; Foucher, I.; Staudt, N.; Peukert, D.; Lumsden, A.; Houart, C. (2007). "Otx1l, Otx2 and Irx1b establish and position the ZLI in the diencephalon". Development 134 (17): 3167–76. doi:10.1242/dev.001461. PMID 17670791.
- Puelles, L; Rubenstein, JL (2003). "Forebrain gene expression domains and the evolving prosomeric model". Trends in neurosciences 26 (9): 469–76. doi:10.1016/S0166-2236(03)00234-0. PMID 12948657.
- Ishibashi, M; McMahon, AP (2002). "A sonic hedgehog-dependent signaling relay regulates growth of diencephalic and mesencephalic primordia in the early mouse embryo". Development 129 (20): 4807–19. PMID 12361972.
- Kiecker, C; Lumsden, A (2004). "Hedgehog signaling from the ZLI regulates diencephalic regional identity". Nature Neuroscience 7 (11): 1242–9. doi:10.1038/nn1338. PMID 15494730.
- Scholpp, S.; Wolf, O; Brand, M; Lumsden, A (2006). "Hedgehog signalling from the zona limitans intrathalamica orchestrates patterning of the zebrafish diencephalon". Development 133 (5): 855–64. doi:10.1242/dev.02248. PMID 16452095.
- Scholpp, S.; Delogu, A.; Gilthorpe, J.; Peukert, D.; Schindler, S.; Lumsden, A. (2009). "Her6 regulates the neurogenetic gradient and neuronal identity in the thalamus". Proceedings of the National Academy of Sciences 106 (47): 19895–900. doi:10.1073/pnas.0910894106. PMC 2775703. PMID 19903880. //www.ncbi.nlm.nih.gov/pmc/articles/PMC2775703/.
- Vue, Tou Yia; Bluske, Krista; Alishahi, Amin; Yang, Lin Lin; Koyano-Nakagawa, Naoko; Novitch, Bennett; Nakagawa, Yasushi (2009). "Sonic Hedgehog Signaling Controls Thalamic Progenitor Identity and Nuclei Specification in Mice". Journal of Neuroscience 29 (14): 4484–97. doi:10.1523/JNEUROSCI.0656-09.2009. PMC 2718849. PMID 19357274. //www.ncbi.nlm.nih.gov/pmc/articles/PMC2718849/.
- Young, Keith A.; Holcomb, Leigh A.; Bonkale, Willy L.; Hicks, Paul B.; Yazdani, Umar; German, Dwight C. (2007). "5HTTLPR Polymorphism and Enlargement of the Pulvinar: Unlocking the Backdoor to the Limbic System". Biological Psychiatry 61 (6): 813–8. doi:10.1016/j.biopsych.2006.08.047. PMID 17083920.
- Dejerine, J.; Roussy, G. (1906). "Le syndrome thalamique". Revue Neurologique 14: 521–32.
- Gray, H. & Carter, H. V. (1858), Anatomy Descriptive and Surgical, London: John W. Parker and Son, Retrieved (16 October 2011) [2012-02-10] → 
|Wikimedia Commons has media related to: Thalamus|
- BrainMaps at UCDavis thalamus
全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.
- 1. ラクナ梗塞 lacunar infarcts
- 2. 感覚消失患者へのアプローチ approach to the patient with sensory loss
- 3. 後方循環系の脳血管症候群 posterior circulation cerebrovascular syndromes
- 4. 視床下部下垂体軸 hypothalamic pituitary axis
- 5. クライネ・レビン症候群（反復性過眠症） kleine levin syndrome recurrent hypersomnia
- Morphology and morphometry of the human embryonic brain: A three-dimensional analysis.
- Shiraishi N,Katayama A,Nakashima T,Yamada S,Uwabe C,Kose K,Takakuwa T
- NeuroImage 115, 96-103, 2015-04-28
- … The anatomical positions of the COR were mostly consistent with the formation of the basal ganglia, thalamus, and pyramidal tract. …
- NAID 120005619798
- 佐々木 拓也,中山 貴博,北村 美月,角田 幸雄,今福 一郎
- 臨床神経学 advpub(0), 2015
- 症例は55歳女性である．7年前に左顔面の異常感覚と右視床病変を生じたが自然消失した．1年前より右上下肢運動障害と両側基底核病変が出現・増悪した．続いて左後頭葉病変が新出し視神経炎も併発した．経過中，ステロイド反応性のぶどう膜炎を2度発症した．長期にわたる増悪寛解型の経過より当初は多発性硬化症などの炎症性疾患を考えたが，ステロイド治療の効果が不十分だったため脳生検を施行し，びまん性大細胞型B細胞性リ …
- NAID 130005087473
- 山本 昌昭
- Neuro-Oncologyの進歩 22(1), 9-18, 2015
- … He devised a treatment which, instead of stereotactic surgery in which infection and/or hemorrhage inevitably occurred at certain incidences, cross-fired ionizing beams from multiple directions to produce a small lesion in deep brain structures, e.g., the thalamus, basal ganglia and so on, with no risk of such complications. …
- NAID 130005075307
|拡張検索||「autoimmune hypothalamus hypophyseal inflammation」|
- 図：N.105 B.41 KL.719