Interposed nucleus

Structure in cerebellum that modulates muscle stretch reflexes of proximal limb muscles.
Interposed nucleus
Details
Identifiers
Latinnucleus interpositus anterior, nucleus interpositus posterior
NeuroLex IDnlx_anat_20081242
Anatomical terms of neuroanatomy
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The interposed nuclei are the globose and emboliform nucleus or either side, collectively.[1] It is located in the roof (dorsal aspect) of the fourth ventricle, lateral to the fastigial nucleus.

The interposed nucleus is responsible for coordinating agonist/antagonist muscle pairs, and therefore a lesion in this area causes tremor.

Anatomy

The interposed nucleus is located in the paravermis of the cerebellum.[citation needed]

The interposed nucleus is smaller than the dentate but larger than the fastigial nucleus.[citation needed]

Afferents

The interposed nuclei receives Purkine cell terminal afferents from the paravermal cortex of the spinocerebellum, as well as collaterals of cerebellar afferents from the restiform body and anterior spinocerebellar tract.[1]

It receives input from the ipsilateral posterior external arcuate fibers (cuneocerebellar tract) and the dorsal spinocerebellar tract, which originate in the accessory cuneate nucleus and the posterior thoracic nucleus, respectively.[citation needed]

Efferents

Afferents from the interposed nuclei leave the cerebellum through the brachium conjunctivum of the superior cerebellar peduncle. They project to:[1]

  • contralateral (magnocellular division of) the red nucleus (→ rubrospinal tract). The red nucleus is the main target of tne interposed nuclei.[1]
  • ipsilateral ventral lateral nucleus of thalamus (→ premotor cortex and primary motor cortex → lateral corticospinal tract).[1]

The rubrospinal and lateral corticospinal tracts are subsequently involved in control of the distal musculature of the extremities.[1]

Function

Functionally, it modulates muscle stretch reflexes of proximal limb muscles. The cerebellar interpositus nucleus is also required in delayed Pavlovian conditioning.[2]

References

  1. ^ a b c d e f Patestas, Maria A.; Gartner, Leslie P. (2016). A Textbook of Neuroanatomy (2nd ed.). Hoboken, New Jersey: Wiley-Blackwell. p. 292. ISBN 978-1-118-67746-9.
  2. ^ Clark, Robert E.; Zhang, Andrew A.; Lavond, David G. (1992). "Reversible lesions of the cerebellar interpositus nucleus during acquisition and retention of a classically conditioned behavior". Behavioral Neuroscience. 106 (6): 879–888. doi:10.1037/0735-7044.106.6.879. PMID 1335267.

External links

  • https://web.archive.org/web/20080405060224/http://www.lib.mcg.edu/edu/eshuphysio/program/section8/8ch6/s8ch6_30.htm
  • http://www.neuroanatomy.wisc.edu/cere/text/P5/interp.htm
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