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a brief treatise on a subject of interest; published in the form of a booklet (同)pamphlet
an extended area of land (同)piece of land, piece of ground, parcel of land, parcel
a system of body parts that together serve some particular purpose
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the act of drawing a plan or diagram or outline
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広大な土地(地域),(土地・海・空などの)広がり《+of+名》 / (器官の)管,(神経の)索
(おもに宗教・政治などの宣伝用の)小冊子,パンフレット
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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/03/09 09:47:28」(JST)

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The spinothalamic tract (also known as anterolateral system or the ventrolateral system) is a sensory pathway from the skin to the thalamus. From the ventral posterolateral nucleus in the thalamus, sensory information is relayed upward to the somatosensory cortex of the postcentral gyrus.

The spinothalamic tract consists of two adjacent pathways: anterior and lateral. The anterior spinothalamic tract carries information about crude touch. The lateral spinothalamic tract conveys pain and temperature.

In the spinal cord, the spinothalamic tract has somatotopic organization. This is the segmental organization of its cervical, thoracic, lumbar, and sacral components, which is arranged from most medial to most lateral respectively.

The pathway decussates at the level of the spinal cord, rather than in the brainstem like the posterior column-medial lemniscus pathway and corticospinal tract.

Structure

There are two main parts of the spinothalamic tract (STT):

The lateral spinothalamic tract transmits pain and temperature.
The anterior spinothalamic tract (or ventral spinothalamic tract) transmits crude touch and firm pressure.

The spinothalamic tract, like the dorsal column-medial lemniscus tract, uses three neurons to convey sensory information from the periphery to conscious level at the cerebral cortex.

Pseudounipolar neurons in the dorsal root ganglion have axons that lead from the skin into the dorsal spinal cord where they ascend or descend one or two vertebral levels via Lissauer's tract and then synapse with secondary neurons in either the substantia gelatinosa of Rolando or the nucleus proprius. These secondary neurons are called tract cells.

The axons of the tract cells cross over (decussate) to the other side of the spinal cord via the anterior white commissure, and to the anterolateral corner of the spinal cord (hence the spinothalamic tract being part of the anterolateral system). Decussation usually occurs 1-2 spinal nerve segments above the point of entry. The axons travel up the length of the spinal cord into the brainstem, specifically the rostral ventromedial medulla.

Traveling up the brainstem, the tract moves dorsally. The neurons ultimately synapse with third-order neurons in several nuclei of the thalamus—including the medial dorsal, ventral posterior lateral, and ventral posterior medial nuclei. From there, signals go to the cingulate cortex, the primary somatosensory cortex, and insular cortex respectively.

Function

The types of sensory information transmitted via the spinothalamic tract are described as affective sensation. This means that the sensation is accompanied by a compulsion to act. For instance, an itch is accompanied by a need to scratch, and a painful stimulus makes us want to withdraw from the pain.

There are two sub-systems identified:

Direct (for direct conscious appreciation of pain)
Indirect (for affective and arousal impact of pain). Indirect projections include
- Spino-Reticulo-Thalamo-Cortical (part of the ascending reticular arousal system, aka ARAS)
- Spino-Mesencephalic-Limbic (for affective impact of pain).

Clinical significance

In contrast to the axons of second-order neurons in posterior column-medial lemniscus pathway, the axons of second-order neurons in the spinothalamic tracts cross at every segmental level in the spinal cord. This fact aids in determining whether a lesion is in the brain or the spinal cord. With lesions in the brain stem or higher, deficits of pain perception, touch sensation, and proprioception are all contralateral to the lesion. With spinal cord lesions, however, the deficit in pain perception is contralateral to the lesion, whereas the other deficits are ipsilateral. See Brown-Séquard syndrome.

Unilateral lesions usually cause contralateral anaesthesia (loss of pain and temperature). Anaesthesia will normally begin 1-2 segments below the level of lesion, affecting all caudal body areas. This is clinically tested by using pin pricks.

Anterolateral system

In the nervous system, the anterolateral system (ALS) is an ascending pathway that conveys pain,^[1] temperature (protopathic sensation), and crude touch from the periphery to the brain. It comprises three main pathways:

Name	Destination	Function
spinothalamic tract (lateral and anterior)	thalamus	important in the localization of painful or thermal stimuli
spinoreticular tract	reticular formation	causes alertness and arousal in response to painful stimuli
spinotectal tract	tectum	orients the eyes and head towards the stimuli

References

^ "Chapter 25:Neural Mechanisms of Cardiac Pain: The Anterolateral System". Retrieved 2009-11-26.

External links

UpToDate Contents

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English Journal

Excitotoxic injury to thoracolumbar gray matter alters sympathetic activation and thermal pain sensitivity.

Vierck CJ, King CD, Berens SA, Yezierski RP.SourceDepartment of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, 32610, USA, vierck@mbi.ufl.edu.
Experimental brain research. Experimentelle Hirnforschung. Experimentation cerebrale.Exp Brain Res.2013 Aug 8. [Epub ahead of print]
Studies of humans, monkeys and rodents have implicated combined gray and white matter damage as important for development of chronic pain following spinal cord injury (SCI). Below-level chronic pain and hyperalgesia following injury to the spinal white matter, including the spinothalamic tract (STT)
PMID 23925342

Bilateral transient changes in thalamic nucleus ventroposterior lateralis after thoracic hemisection in the rat.

Liang L, Mendell LM.SourceDepartment of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York.
Journal of neurophysiology.J Neurophysiol.2013 Aug;110(4):942-51. doi: 10.1152/jn.00998.2012. Epub 2013 Jun 5.
We made simultaneous bilateral recordings of unit activity in the nucleus ventroposterior lateralis (VPL) in intact rats and after acute and chronic left thoracic hemisection. We observed an immediate bilateral decline in multireceptive units, reflecting a loss of nociceptive input on the lesion sid
PMID 23741041

Neural processing of itch.

Akiyama T, Carstens E.SourceUniversity of California, Davis, Department of Neurobiology, Physiology & Behavior, 1 Shields Avenue, Davis, CA 95616, United States.
Neuroscience.Neuroscience.2013 Jul 24. pii: S0306-4522(13)00617-9. doi: 10.1016/j.neuroscience.2013.07.035. [Epub ahead of print]
While considerable effort has been made to investigate the neural mechanisms of pain, much less effort has been devoted to itch, at least until recently. However, itch is now gaining increasing recognition as a widespread and costly medical and socioeconomic issue. This is accompanied by increasing
PMID 23891755

Japanese Journal

Updated Neurophysiology of Itch

Ikoma Akihiko
Biological and Pharmaceutical Bulletin 36(8), 1235-1240, 2013
… The unique physiological features of histamine-sensitive C-fibers and spinothalamic tract neurons support the hypothesis of itch specific pathway, whereas subsequent studies on cowhage-induced itch have provided evidence against it, suggesting the presence of multiple neural pathways for itch. …
NAID 130003361503

顔面をふくまない半身の温痛覚障害のみを呈した延髄外側梗塞の67歳男性例

柏村陽子,川井元晴,小笠原淳一 [他],古賀道明,根来清,神田隆
臨床神経学 49(5), 262-266, 2009-05-01
NAID 10024899499

Central nervous control of micturition and urine storage

SUGAYA Kimio,NISHIJIMA Saori,MIYAZATO Minoru,OGAWA Yoshihide
日本平滑筋学会機関誌 41(3), 117-132, 2005-06-00
… One is the dorsal system and the other is the spinothalamic tract. … Afferents to the PMC ascend in the spinotegmental tract, which run through the lateral funiculus of the spinal cord. …
NAID 110002950124

「脊髄視床路」

Spinothalamic tract
	Spinothalamic tracts are grouped, in blue at bottom right.
	Diagram of the principal fasciculi of the spinal cord. (Anterior and posterior spinothalamic fasciculus is labeled at bottom left.)
Details
Identifiers
Latin	Tractus spinothalamicus
NeuroNames	ancil-114
TA	A14.1.04.138
FMA	72644
	Anatomical terms of neuroanatomy [edit on Wikidata]