In the

human brain The human brain is the central organ (anatomy), organ of the nervous system, and with the spinal cord, comprises the central nervous system. It consists of the cerebrum, the brainstem and the cerebellum. The brain controls most of the activi ...

, the superior cerebellar peduncle (brachium conjunctivum) is one of the three paired cerebellar peduncles of bundled

fibers Fiber (spelled fibre in British English; from ) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often inco ...

that connect the

cerebellum The cerebellum (: cerebella or cerebellums; Latin for 'little brain') is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as it or eve ...

to the

brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is conti ...

. The superior cerebellar peduncle connects to the

midbrain The midbrain or mesencephalon is the uppermost portion of the brainstem connecting the diencephalon and cerebrum with the pons. It consists of the cerebral peduncles, tegmentum, and tectum. It is functionally associated with vision, hearing, mo ...

. It consists mainly of efferent fibers, the cerebellothalamic tract that runs from a

cerebellar hemisphere The cerebellum consists of three parts, a median and two lateral, which are continuous with each other, and are substantially the same in structure. The median portion is constricted, and is called the vermis, from its annulated appearance which ...

to the contralateral

thalamus The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...

, and the cerebellorubral tract that runs from a cerebellar hemisphere to the

red nucleus The red nucleus or nucleus ruber is a structure in the rostral midbrain involved in motor coordination. The red nucleus is pale pink, which is believed to be due to the presence of iron in at least two different forms: hemoglobin and ferritin. ...

. It also contains afferent tracts, most prominent of which is the

ventral spinocerebellar tract The spinocerebellar tracts are nerve tracts originating in the spinal cord and terminating in the same side ( ipsilateral) of the cerebellum. The two main tracts are the dorsal spinocerebellar tract, and the ventral spinocerebellar tract. Both of ...

. Other afferent tracts are the ventral trigeminal tract, tectocerebellar fibers, and noradrenergic fibers from the

locus coeruleus The locus coeruleus () (LC), also spelled locus caeruleus or locus ceruleus, is a nucleus in the pons of the brainstem involved with physiological responses to stress and panic. It is a part of the reticular activating system in the reticular ...

. The superior peduncle emerges from the upper and medial parts of the

white matter White matter refers to areas of the central nervous system that are mainly made up of myelinated axons, also called Nerve tract, tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distr ...

of each cerebellar hemisphere and is placed under cover of the upper part of the cerebellum.

Structure

Superior cerebellar peduncles are connected together by the superior medullary velum, which can be followed upward as far as the inferior colliculi, under which they disappear. Below, they form the upper lateral boundaries of the

fourth ventricle The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ...

, but as they ascend they converge on the dorsal aspect of the ventricle and thus assist in forming its roof.

Decussation

The decussation of superior cerebellar peduncle is the crossing of fibers of the superior cerebellar peduncle across the midline, and is located at the level of the inferior colliculi. It comprises the cerebellothalamic tract, which arises from the

dentate nucleus The dentate nucleus refer to a pair of deep cerebellar nuclei deep within the white matter of the cerebellum of the brain with a dentate – tooth-like or serrated – edge. The dentate forms the largest pathway between the cerebellum and the r ...

(therefore also known as dentatothalamic tract), as well as the cerebellorubral tract, which arises from the

globose This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary ...

and emboliform nuclei and project to the

contralateral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

to eventually become the

rubrospinal tract The rubrospinal tract is one of the descending tracts of the spinal cord. It is a motor control pathway that originates in the red nucleus. It is a part of the lateral indirect extrapyramidal tract. The rubrospinal tract fibers are efferent ne ...

. It is also known as horseshoe-shaped commissure of Wernekinck. It is important as an anatomical landmark, as lesions above it cause contralateral cerebellar signs, while lesions below it cause ipsilateral cerebellar signs.

Additional images

Image:Gray677.png, Scheme showing the connections of the several parts of the brain. Image:Gray682.png, Superficial dissection of brain-stem. Lateral view. Image:Gray701.png, Axial section of the pons, at its dorsal (superior) part. Image:Gray707.png, Sagittal section through right cerebellar hemisphere. The right olive has also been cut sagittally. Image:Gray745.png, Dissection showing the course of the cerebrospinal fibers. Image:Gray792.png, Upper part of medulla spinalis and hind- and mid-brains; posterior aspect, exposed in situ.

References

External links

* * * https://web.archive.org/web/20080518232033/http://isc.temple.edu/neuroanatomy/lab/atlas/micn/ * http://www.neuroanatomy.wisc.edu/Bs97/TEXT/P18/sum.htm
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