Cerebral peduncle
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| Cerebral peduncle | |
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Superficial dissection of brain-stem. Ventral view. ("Cerebral peduncle" visible in red at center-right.)
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Section through superior colliculus showing path of oculomotor nerve. (Crus cerebri labeled at lower left.)
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| Details | |
| Latin | pedunculus cerebri |
| Identifiers | |
| MeSH | A08.186.211.132.659 |
| NeuroNames | hier-478 |
| NeuroLex ID | Central peduncle |
| Dorlands /Elsevier |
p_10/12622555 |
| TA | Lua error in Module:Wikidata at line 744: attempt to index field 'wikibase' (a nil value). |
| TH | {{#property:P1694}} |
| TE | {{#property:P1693}} |
| FMA | {{#property:P1402}} |
| Anatomical terms of neuroanatomy
[[[d:Lua error in Module:Wikidata at line 863: attempt to index field 'wikibase' (a nil value).|edit on Wikidata]]]
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Mainly, the three common areas that give rise to the cerebral peduncles are the cortex, the spinal cord and the cerebellum.[1] The cerebral peduncle, by most classifications, is everything in the mesencephalon except the tectum.[citation needed] The region includes the midbrain 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 crus cerebri or the pes pedunculi.
The cerebral peduncles are located on either side of the mid brain and are the most anterior part of the midbrain, they act as the connectors between the rest of the midbrain and the thalamic nuclei and thus the cerebrum. As a whole, the cerebral peduncles assists in refining motor movements, learning of new motor skills, and converting proprioceptive information into balance and posture maintenance.[2][3] The cerebral peduncles consist of three cerebellar peduncles on each side of the mid brain, which act as connections between the cerebellum and the brainstem. The axon fiber bundles that act as the connections can either perform input or output tasks depending on the type of signal they receive. These are the three input and output tracts of the cerebellum: superior (brachium conjunctivum), middle (brachium pontis), and inferior (restiform body) cerebellar peduncles. Important fiber tracts that run through the cerebral peduncles are: cortico-spinal, cortico-pontine, and cortico-bulbar tracts.
Damage to the cerebral peduncles results in unrefined motor skills, imbalance, and lack of proprioception.[4]
Contents
Structure
The descending fibers from the internal capsule continue on through the midbrain and are then seen as the fibers in the cerebral peduncles.[5] The superior, middle, and inferior cerebral peduncles connect the brain stem to the cerebellum. The superior peduncle connects the cerebellum to the midbrain, while the middle peduncle connects the pons to the cerebellum. The middle peduncle is the largest of the peduncles.[6] The inferior peduncle connects the medulla to the cerebellum. In terms of input and output signals, the middle and inferior peduncles are the primary peduncles for input information. While output from the cerebellum is via the superior peduncle.[6] The superior peduncle also connects the interposed nuclei to the red nucleus, as well as the dentate nucleus to the ventral lateral nucleus of the thalamus which relays to the cerebral motor cortex.[6]
| Superior peduncle (brachium conjunctivum) | Middle peduncle (brachium pontis) | Inferior peduncle (restiform body) |
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| Coordination of the arms and legs, as well as transportation of information from the cerebellum to the midbrain and pons. Acts primarily as output from the cerebellum. | Originates at the pontine nuclei. There are three types of nervous tissue: superior, inferior, and deep. Connects the pons to the cerebellum, assists in the intention for motor control. Largest of the peduncles, acts primarily as an input to the cerebellum. | Responsible for proprioceptive information. Accomplishes this by connecting the cerebellum to the medulla. Acts primarily as an input to the cerebellum. |
Fiber tracts
The contralateral red nucleus is the origin for the rubrospinal tract whose main function is to influence limb flexor muscles. The superior cerebellar peduncle facilitates the connection between the interposed nuclei and the red nucleus. The pontine nuclei exclusively connect to the cerebellum via the middle peduncle forming the cortico- pontine tract.[6] The cortico-pontine fibers are found in the outer and inner third of the cerebral peduncle, these are the cortical input to the pontine nuclei.[8] The cortico-bulbar and cortico-spinal fibers are found in the middle third of the cerebral peduncle.[9] The cortico-spinal tract exits the internal capsule and is seen in the mid portion of the cerebral peduncles.
Cranial nerves
Cranial nerve 5 (trigeminal nerve) is attached along the middle cerebral peduncle. Cranial nerve 3 (oculomotor nerve) appears ventrally between the two cerebral peduncles in the interpeduncular fossa. Cranial nerve 4 (trochlear nerve) wraps around the lowest part of the cerebral peduncle.[10]
Additional images
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Scheme showing the connections of the several parts of the brain.
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Deep dissection of brain-stem. Lateral view.
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Dissection showing the projection fibers of the cerebellum.
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Median sagittal section of brain.
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The left optic nerve and the optic tracts.
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Upper part of medulla spinalis and hind- and mid-brains; posterior aspect, exposed in situ.
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Human brainstem anterior view
See also
References
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