Spinotectal tract | |
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Details | |
Identifiers | |
Latin | tractus spinotectalis |
TA98 | A14.1.02.224 A14.1.04.141 |
TA2 | 6107 |
FMA | 73968 |
Anatomical terminology |
The spinotectal tract and/or spinomesencephalic tract (also spinotectal fibers, spinomesencephalic fibers,[1] spinotectal fasciculus, or spino-quadrigeminal system of Mott[2]) is one of the ascending tracts in the anterolateral system of the spinal cord that is involved in processing of pain and visceral sensations.[3] The tract is involved in the processing of pain sensation, and reflex turning of the head and trunk in the direction of painful stimuli.[1] It projects contralaterally to the midbrain tectum.
Sources may distinguish between a distinct spinotectal tract which projects to the visual reflex system, and spinomesencephalic tract which projects to structures involved in pain processing.[1]
Anatomy
[edit]The ST/SM tract mostly consists of myelinated fibers. It conveys stimuli from disparate sensory afferents (low/high threshold, small/large receptive fields, wide dinamic range).[4]
Origin
[edit]The ST/SM tract arises mostly in the laminae I and V (but, to a lesser extent, also laminae IV and VI-VIII) of the spinal cord.[4] It arises in same region of the spinal cord grey matter as the spinothalamic tracts.[3]
Course
[edit]It mostly crosses over (decussates) to ascend contralaterally, but uncrossed ipsilaterally ascending fibers are prominent in the upper cervical levels.[4]
In the spinal cord, it ascends in its anterolateral quadrant - alongside the spinothalamic tract and spinoreticular tracts.[4]
Projections
[edit]Note: rightward arrows indicate subsequent functionally relevant "downstream" projections/pathways of some targets of the ST/SM tract.
- Periaqueductal gray (PAG) → nucleus raphe magnus and gigantocellular reticular nucleus of the reticular formation of the medulla oblongata (enkephalinergic excitatory synapse) - modulates nociception through the serotonergic-opioid peptide descending pain-inhibiting system.[1] Stimulation of the area of PAG into which the ST/SM tract elicits excruciating pain.[4]
- Nuclei of the reticular formation[3]
- Mesencephalic raphe nuclei - modulate nociception through the serotonergic-enkephalinergic opioid peptide descending pain-inhibiting system.[1]
- Parabrachial nucleus → amygdala (the latter being involved in processing affective responses).[1]
- Superior colliculus → tectospinal tract (mediates reflex movement of the head and eyes in the direction of origin of a noxious sensation).[1]
- Pretectum[1]
- Nucleus of Darkschewitsch[4]
- Interstitial nucleus of Cajal[4]
See also
[edit]References
[edit]- ^ a b c d e f g h Patestas, Maria A.; Gartner, Leslie P. (2016). A Textbook of Neuroanatomy (2nd ed.). Hoboken, New Jersey: Wiley-Blackwell. pp. 112, 203–204, 224–225. ISBN 978-1-118-67746-9.
- ^ Gray, Henry (1918). Gray's Anatomy (20th ed.). p. 762.
- ^ a b c Kiernan, John A.; Rajakumar, Nagalingam (2013). Barr's The Human Nervous System: An Anatomical Viewpoint (10th ed.). Philadelphia: Wolters Kluwer Lippincott Williams & Wilkins. p. 74. ISBN 978-1-4511-7327-7.
- ^ a b c d e f g Standring, Susan (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice (42th ed.). New York: Elsevier. pp. 433.e1, 458.e1. ISBN 978-0-7020-7707-4. OCLC 1201341621.
External links
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