Inferior cerebellar peduncle

Inferior cerebellar peduncle
Scheme showing the connections of the several parts of the brain. (Inferior peduncle labeled at bottom right.)
Section of the medulla oblongata at about the middle of the olive. (Inferior peduncle labeled at upper right.
Details
Identifiers
Latin	pedunculus cerebellaris inferior
NeuroNames	hier-778
NeuroLex ID	Inferior cerebellar peduncle
Dorlands /Elsevier	p_10/12622504
TA	A14.1.04.013
FMA	72615
*Anatomical terms of neuroanatomy* [edit on Wikidata]

The upper part of the posterior district of the medulla oblongata is occupied by the inferior cerebellar peduncle (restiform body), a thick rope-like strand situated between the lower part of the fourth ventricle and the roots of the glossopharyngeal and vagus nerves.

Each cerebellar inferior peduncle connects the spinal cord and medulla oblongata with the cerebellum, and comprises the juxtarestiform body and restiform body.

Important fibers running through the inferior cerebellar peduncle include the dorsal spinocerebellar tract and axons from the inferior olivary nucleus, among others.

Function

The inferior cerebellar peduncle carries many types of input and output fibers that are mainly concerned with integrating proprioceptive sensory input with motor vestibular functions such as balance and posture maintenance. It consists of the following fiber tracts entering cerebellum:

Posterior spinocerebellar tract: unconsciouness proprioceptive information from the lower part of trunk and lower limb. This tract originates at the ipsilateral Clarke's nucleus (T1-L1) and travels upward to reach the inferior cerebellar peduncle and synapses within the spinocerebellum (also known as the paleocerebellum).
Cuneocerebellar tract: unconsciousness proprioceptive information from the upper limb and neck. This tract originates at the ipsilateral accessory cuneate nucleus and travels through the inferior cerebellar peduncle to reach the spinocerebellum part of the cerebellum.
Trigeminocerebellar tract: unconsciousness proprioceptive information from the face.
Olivocerebellar tract: "error signal" in movement originates from the cerebral cortex and spinal cord. This tract originates at contralateral inferior olivary nucleus and enters the cerebellum as a climbing fiber.
Vestibulocerebellar tract: vestibular information projects onto the vestibulocerebellum (also known as the archicerebellum).

This peduncle also carries information leaving cerebellum: from the Purkinje cells to the vestibular nuclei in the dorsal brainstem located at the junction between the pons and medulla oblongata.

Additional images

Upper part of medulla spinalis and hind- and mid-brains; posterior aspect, exposed in situ.
Superficial dissection of brain-stem. Lateral view.
Dissection of brain-stem. Lateral view.
Deep dissection of brain-stem. Lateral view.
Dissection of brain-stem. Dorsal view.
Diagram showing the course of the arcuate fibers.
Dissection showing the course of the cerebrospinal fibers.
Cross section of lower pons showing part of the inferior cerebellar peduncle (#8) labeled at the upper left.
Cerebellum. Inferior surface.
Cerebellum. Inferior surface.
Cerebellum. Inferior surface.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

External links

Atlas image: n2a5p2 at the University of Michigan Health System
Atlas image: n2a7p4 at the University of Michigan Health System
Illustration and text: cere/text/p1/icp.htm at the University of Wisconsin-Madison Medical school

Anatomy of the medulla

Grey matter

Cranial nuclei

afferent:	Solitary nucleus tract Dorsal respiratory group Gustatory nucleus Vestibular nuclei Lateral Medial Inferior

efferent:	Hypoglossal nucleus Nucleus ambiguus Dorsal nucleus of vagus nerve Inferior salivatory nucleus

Dorsal

Ventral

White matter

Dorsal	Sensory Sensory decussation Medial lemniscus Juxtarestiform body Ascending dorsal longitudinal fasciculus Medial longitudinal fasciculus Motor Descending dorsal longitudinal fasciculus Medial longitudinal fasciculus

Ventral	Descending tracts Olivocerebellar tract Rubro-olivary tract

Surface

Front	Pyramid decussation Anterior median fissure Anterolateral sulcus Olive Inferior olivary nucleus

Back	Posterior median sulcus Posterolateral sulcus Area postrema Vagal trigone Hypoglossal trigone Medial eminence Inferior cerebellar peduncle

Grey

Anatomy of the cerebellum

Surface

Lobes	Anterior lobe Posterior lobe Horizontal fissure Flocculonodular lobe Flocculus Nodule Primary fissure

Medial/lateral	Vermis: anterior Central lobule Culmen Lingula posterior Folium Tuber Uvula Vallecula of cerebellum Hemisphere: anterior Alar central lobule posterior Biventer lobule Cerebellar tonsil

Grey matter

Deep cerebellar nuclei	Dentate interposed Emboliform Globose Fastigial

Cerebellar cortex	Molecular layer Stellate cell Basket cell Purkinje cell layer Purkinje cell Bergmann glia cell = Golgi epithelial cell Granule cell layer Golgi cell Granule cell Unipolar brush cell Fibers: Mossy fibers Climbing fiber Parallel fiber

White matter

Internal	Arbor vitae

Peduncles	Inferior (medulla): Dorsal spinocerebellar tract Olivocerebellar tract Cuneocerebellar tract Juxtarestiform body (Vestibulocerebellar tract) Trigeminocerebellar fibers Middle (pons): Pontocerebellar fibers Superior (midbrain): Ventral spinocerebellar tract Dentatothalamic tract

Brain and spinal cord: neural tracts and fasciculi

Sensory/
ascending

PCML

1°:	Pacinian corpuscle/Meissner's corpuscle → Posterior column (Gracile fasciculus/Cuneate fasciculus) → Gracile nucleus/Cuneate nucleus

2°:	→ sensory decussation/arcuate fibers (Posterior external arcuate fibers, Internal arcuate fibers) → Medial lemniscus/Trigeminal lemniscus → Thalamus (VPL, VPM)

3°:	→ Posterior limb of internal capsule → Postcentral gyrus

Anterolateral/
pain

Fast/lateral	1° (Free nerve ending → A delta fiber) → 2° (Anterior white commissure → Lateral and Anterior Spinothalamic tract → Spinal lemniscus → VPL of Thalamus) → 3° (Postcentral gyrus) → 4° (Posterior parietal cortex) 2° (Spinomesencephalic tract → Superior colliculus of Midbrain tectum)

Slow/medial	1° (Group C nerve fiber → Spinoreticular tract → Reticular formation) → 2° (MD of Thalamus) → 3° (Cingulate cortex)

Motor/
descending

Pyramidal

flexion: Primary motor cortex → Posterior limb of internal capsule → Decussation of pyramids → Corticospinal tract (Lateral, Anterior) → Neuromuscular junction

Extrapyramidal

flexion:	Primary motor cortex → Genu of internal capsule → Corticobulbar tract → Facial motor nucleus → Facial muscles

flexion:	Red nucleus → Rubrospinal tract

extension:	Vestibulocerebellum → Vestibular nuclei → Vestibulospinal tract

extension:	Vestibulocerebellum → Reticular formation → Reticulospinal tract

Midbrain tectum → Tectospinal tract → muscles of neck

Basal ganglia

direct:	1° (Motor cortex → Striatum) → 2° (GPi) → 3° (Lenticular fasciculus/Ansa lenticularis → Thalamic fasciculus → VL of Thalamus) → 4° (Thalamocortical radiations → Supplementary motor area) → 5° (Motor cortex)

indirect:	1° (Motor cortex → Striatum) → 2° (GPe) → 3° (Subthalamic fasciculus → Subthalamic nucleus) → 4° (Subthalamic fasciculus → GPi) → 5° (Lenticular fasciculus/Ansa lenticularis → Thalamic fasciculus → VL of Thalamus) → 6° (Thalamocortical radiations → Supplementary motor area) → 7° (Motor cortex)

nigrostriatal pathway:	Pars compacta → Striatum

Cerebellar

Afferent

Vestibular nuclei → Vestibulocerebellar tract → ICP → Cerebellum → Granule cell

Pontine nuclei → Pontocerebellar fibers → MCP → Deep cerebellar nuclei → Granule cell

Inferior olivary nucleus → Olivocerebellar tract → ICP → Hemisphere → Purkinje cell → Deep cerebellar nuclei

Efferent

Dentate nucleus in Lateral hemisphere/pontocerebellum → SCP → Dentatothalamic tract → Thalamus (VL) → Motor cortex

Interposed nucleus in Intermediate hemisphere/spinocerebellum → SCP → Reticular formation, or → Cerebellothalamic tract → Red nucleus → Thalamus (VL) → Motor cortex

Fastigial nucleus in Flocculonodular lobe/vestibulocerebellum → Vestibulocerebellar tract → Vestibular nuclei

Bidirectional:
Spinocerebellar

Unconscious proprioception	lower limb → 1° (muscle spindles → DRG) → 2° (Posterior thoracic nucleus → Dorsal/posterior spinocerebellar tract → ICP → Cerebellar vermis) upper limb → 1° (muscle spindles → DRG) → 2° (Accessory cuneate nucleus → Cuneocerebellar tract → ICP → Anterior lobe of cerebellum)

Reflex arc	lower limb → 1° (Golgi tendon organ) → 2° (Ventral/anterior spinocerebellar tract→ SCP → Cerebellar vermis) upper limb → 1° (Golgi tendon organ) → 2° (Rostral spinocerebellar tract → ICP → Cerebellum)

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Inferior cerebellar peduncle

Function

See also

Additional images

References

External links