Pontine nuclei

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Pontine nuclei
Lower pons horizontal KB.svg
Cross section through the lower pons showing the pontine nuclei (#22) and the pontocerebellar fibers emerging from them to become the middle cerebellar peduncle
Details
Identifiers
Latin nuclei pontis
NeuroNames 617
NeuroLex ID birnlex_1516
TA98 A14.1.05.202
TA2 5926
FMA 72512
Anatomical terms of neuroanatomy

The pontine nuclei (or griseum pontis) are all the neurons of the ventral pons. Corticopontine fibres project from the primary motor cortex to the ipsilateral pontine nucleus; pontocerebellar fibers then relay the information to the contralateral cerebellum via the middle cerebellar peduncle.

Contents

They are involved in motor function: the pontine nuclei are involved in adjusting movements according to their outcome (movement error correction), and are therefore important in learning motor skills.[ citation needed ]

Anatomy

The pontine nuclei encompass all of the about 20 million neurons scattered throughout the basilar part of pons. [1] The pontine nuclei nuclei extend caudally into the medulla oblongata as the arcuate nucleus which is functionally homologous with the pontine nuclei.[ citation needed ]

Afferents

Corticopontine fibres arise primarily from the neocortex layer V of the premotor, somatosensory, non-striate visual, posterior parietal, and cingulate cerebral cortex; there are also a few fibers originating from the prefrontal, temporal, and striate cortex. [1]

Pontine nuclei also receive afferents from the lateral geniculate nucleus, superior colliculus, pretectal nuclei, hypothalamus, medial mammillary nucleus, cerebellum trigeminal nuclei, dorsal column nuclei, locus coeruleus, periaqueductal gray, raphe nuclei, and reticular formation. [1]

Efferents

Pontocerebellar fibers are the sole efferent pathway of the pontine nuclei. The fibers mostly decussate within the pons to pass through the (contralateral) middle cerebellar peduncle to terminate in the contralateral cerebellum as mossy fibers; they form terminal synapses in the cerebellar cortex, but also issue collaterals to the cerebellar nuclei. [1]

Neurophysiology

Likely, all of the neurons of the pontine nuclei are glutaminergic. [1]

See also

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<span class="mw-page-title-main">Pons</span> Part of the brainstem in humans and other bipeds

The pons is part of the brainstem that in humans and other mammals, lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum.

<span class="mw-page-title-main">Brainstem</span> Posterior part of the brain, adjoining and structurally continuous

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<span class="mw-page-title-main">Cerebral peduncle</span> Stalks that attach the cerebrum to the brainstem

The cerebral peduncles are the two stalks that attach the cerebrum to the brainstem. They are structures at the front of the midbrain which arise from the ventral pons and contain the large ascending (sensory) and descending (motor) tracts that run to and from the cerebrum from the pons. Mainly, the three common areas that give rise to the cerebral peduncles are the cerebral cortex, the spinal cord and the cerebellum. The region includes the tegmentum, crus cerebri and pretectum. By this definition, the cerebral peduncles are also known as the basis pedunculi, while the large ventral bundle of efferent fibers is referred to as the cerebral crus or the pes pedunculi.

<span class="mw-page-title-main">Internal capsule</span> White matter structure situated in the inferomedial part of each cerebral hemisphere of the brain

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<span class="mw-page-title-main">Inferior cerebellar peduncle</span>

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<span class="mw-page-title-main">Dentate nucleus</span> Nucleus in the centre of each cerebellar hemisphere

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<span class="mw-page-title-main">Fastigial nucleus</span> Grey matter nucleus in the cerebellum

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<span class="mw-page-title-main">Flocculus</span>

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<span class="mw-page-title-main">Middle cerebellar peduncle</span> Structure in the brain connecting the pons to the cerebellum

The middle cerebellar peduncle is one of three paired cerebellar peduncles connecting the brainstem to the cerebellum. The connection is from the pons. It connects the pons to the cerebellum, with fibres originating from the pontine nuclei, and travelling to the opposite cerebellar hemisphere. It is supplied by the anterior inferior cerebellar artery (AICA) and branches from the basilar artery. It conveys information from the cerebrum and the pons to the cerebellum.

The projection fibers consist of efferent and afferent fibers uniting the cortex with the lower parts of the brain and with the spinal cord. In human neuroanatomy, bundles of axons called tracts, within the brain, can be categorized by their function into association fibers, projection fibers, and commissural fibers.

<span class="mw-page-title-main">Frontopontine fibers</span> Frontal lobe

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The reticulotegmental nucleus, tegmental pontine reticular nucleus is an area within the floor of the pons, in the brain stem. This area is known to affect the cerebellum with its axonal projections.

<span class="mw-page-title-main">Basilar part of pons</span>

The basilar part of pons, also known as basis pontis, or basilar pons, is the ventral part of the pons in the brainstem; the dorsal part is known as the pontine tegmentum.

<span class="mw-page-title-main">Pontocerebellar fibers</span>

The pontocerebellar fibers are the second-order neuron fibers of the corticopontocerebellar tracts that cross to the other side of the pons and run within the middle cerebellar peduncles, from the pons to the contralateral cerebellum. They arise from the pontine nuclei as the second part of the corticopontocerebellar tract, and decussate (cross-over) in the pons before passing through the middle cerebellar peduncles to reach and terminate in the contralateral posterior lobe of the cerebellum (neocerebellum). It is part of a pathway involved in the coordination of voluntary movements.

<span class="mw-page-title-main">Central tegmental tract</span>

The central tegmental tract is a structure in the midbrain and pons. It is situated in the central portion of the reticular formation. It contains:

<span class="mw-page-title-main">Corticopontine fibers</span> Projections from the cerebral cortex to the pontine nuclei

Corticopontine fibers are projections from layer V of the cerebral cortex to the pontine nuclei of the ventral pons. They represent the first link in a cortico-cerebello-cortical pathway mediating neocerebellar control of the motor cortex. The pathway is especially important for voluntary movements.

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The Anatomy of the Cerebellum can be viewed at three levels. At the level of gross anatomy, the cerebellum consists of a tightly folded and crumpled layer of cortex, with white matter underneath, several deep nuclei embedded in the white matter, and a fluid-filled ventricle in the middle. At the intermediate level, the cerebellum and its auxiliary structures can be broken down into several hundred or thousand independently functioning modules or compartments known as microzones. At the microscopic level, each module consists of the same small set of neuronal elements, laid out with a highly stereotyped geometry.

References

  1. 1 2 3 4 5 Standring, Susan (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice (42th ed.). New York: Elsevier. pp. 451–452. ISBN   978-0-7020-7707-4. OCLC   1201341621.