Latin pedunculus cerebri NeuroNames hier-478 Dorlands
/Elsevier p_10/12622555 | MeSH A08.186.211.132.659 NeuroLex ID Central peduncle | |
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The cerebral peduncles are structures at the front of the midbrain which arise from the front of the pons and contain the large ascending (sensory) and descending (motor) nerve 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 cerebral peduncle, by most classifications, is everything in the mesencephalon except the tectum. 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.
Contents
The cerebral peduncles are located on either side of the mid brain and are the most anterior part of the midbrain, and 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. 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.
Structure
The descending upper fibers from the internal capsule continue on through the midbrain and are then seen as the fibers in the cerebral peduncles. 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. The cortico-bulbar and cortico-spinal fibers are found in the middle third of the cerebral peduncle. The cortico-spinal tract exits the internal capsule and is seen in the mid portion of the cerebral peduncles.
Cranial nerves
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.