Red nucleus
Encyclopedia
The red nucleus is a structure in the rostral midbrain involved in motor coordination
. It comprises a caudal magnocellular
and a rostral parvocellular
part.
, gait
is mainly controlled by the red nucleus.
However, where the corticospinal tract
is dominant, the rubrospinal tract
may be considered to be vestigial. Therefore, here the red nucleus is less important in motor functions than in many other mammals. However, the crawling
of babies is controlled by the red nucleus, as is arm-swinging in normal walking. The red nucleus may play an additional role in controlling muscles of the shoulder
and upper arm via projections of its magnocellular part. In humans the red nucleus also has sparse control over hands, as the rubrospinal tract
is more involved in large muscle movement such as that for arms (but not the legs, as the tract terminates in the superior thoracic region of the spinal cord). Fine control of the fingers is not modified by the functioning of the red nucleus (rather it relies on the corticospinal tract
). The majority of red nucleus axons do not project to the spinal cord
, but instead (via its parvocellular part) relay information from the motor cortex
to the cerebellum
through the inferior olivary complex- an important relay center in the medulla
.
(interposed nucleus
and lateral cerebellar nucleus) and an input from the ipsilateral motor cortex.
It sends efferent axon
s (the rubrospinal projection) to the contralateral half of the rhombencephalic
reticular formation
and spinal cord
. These efferent
axons cross just ventral to the anterior tegmental decussation and descend through the midbrain to the spinal cord, where the rubrospinal tract
which they make up runs ventral to the lateral corticospinal tract
in the lateral funiculus
. Second bundle of fibers continues ipsilaterally through the medial tegmental
field towards inferior olive
.
Motor coordination
thumb|right|Motor coordination is shown in this animated sequence by [[Eadweard Muybridge]] of himself throwing a diskMotor coordination is the combination of body movements created with the kinematic and kinetic parameters that result in intended actions. Such movements usually smoothly and...
. It comprises a caudal magnocellular
Magnocellular red nucleus
The magnocellular red nucleus is located in the rostral midbrain and is involved in motor coordination. Together with the parvocellular red nucleus, it makes up the red nucleus....
and a rostral parvocellular
Parvocellular red nucleus
The parvocellular red nucleus is located in the rostral midbrain and is involved in motor coordination. Together with the magnocellular red nucleus, it makes up the red nucleus....
part.
Function
In animals without a significant corticospinal tractCorticospinal tract
The corticospinal or pyramidal tract is a collection of axons that travel between the cerebral cortex of the brain and the spinal cord....
, gait
Gait
Gait is the pattern of movement of the limbs of animals, including humans, during locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on speed, terrain, the need to maneuver, and energetic efficiency...
is mainly controlled by the red nucleus.
However, where the corticospinal tract
Corticospinal tract
The corticospinal or pyramidal tract is a collection of axons that travel between the cerebral cortex of the brain and the spinal cord....
is dominant, the rubrospinal tract
Rubrospinal tract
The rubrospinal tract is a part of the nervous system. It is a part of the lateral indirect extra-pyramidal tract.-Function:In humans, the rubrospinal tract is one of several major motor control pathways. It is smaller and has fewer axons than the corticospinal tract, suggesting that it is less...
may be considered to be vestigial. Therefore, here the red nucleus is less important in motor functions than in many other mammals. However, the crawling
Crawling (human)
Babies usually learn to crawl before they develop walking skills.Crawls can refer to the specific gait or to any gait involving the arms and legs.Crawling is used mainly:...
of babies is controlled by the red nucleus, as is arm-swinging in normal walking. The red nucleus may play an additional role in controlling muscles of the shoulder
Shoulder
The human shoulder is made up of three bones: the clavicle , the scapula , and the humerus as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder make up the shoulder joints. The major joint of the shoulder is the glenohumeral joint, which...
and upper arm via projections of its magnocellular part. In humans the red nucleus also has sparse control over hands, as the rubrospinal tract
Rubrospinal tract
The rubrospinal tract is a part of the nervous system. It is a part of the lateral indirect extra-pyramidal tract.-Function:In humans, the rubrospinal tract is one of several major motor control pathways. It is smaller and has fewer axons than the corticospinal tract, suggesting that it is less...
is more involved in large muscle movement such as that for arms (but not the legs, as the tract terminates in the superior thoracic region of the spinal cord). Fine control of the fingers is not modified by the functioning of the red nucleus (rather it relies on the corticospinal tract
Corticospinal tract
The corticospinal or pyramidal tract is a collection of axons that travel between the cerebral cortex of the brain and the spinal cord....
). The majority of red nucleus axons do not project to the spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
, but instead (via its parvocellular part) relay information from the motor cortex
Motor cortex
Motor cortex is a term that describes regions of the cerebral cortex involved in the planning, control, and execution of voluntary motor functions.-Anatomy of the motor cortex :The motor cortex can be divided into four main parts:...
to the cerebellum
Cerebellum
The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...
through the inferior olivary complex- an important relay center in the medulla
Medulla
Medulla refers to the middle of something and derives from the Latin word for marrow. Its anatomical uses include:* Medulla oblongata, a part of the brain stem* Renal medulla, a part of the kidney* Adrenal medulla, a part of the adrenal gland...
.
Input and output
The red nucleus receives many inputs from the contralateral cerebellumCerebellum
The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...
(interposed nucleus
Interposed nucleus
The interposed nucleus is a deep nucleus of the cerebellum and is composed of the globose nuclei and the emboliform nuclei. It is located in the roof of the fourth ventricle, lateral to the fastigial nucleus...
and lateral cerebellar nucleus) and an input from the ipsilateral motor cortex.
It sends efferent axon
Axon
An axon is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body or soma....
s (the rubrospinal projection) to the contralateral half of the rhombencephalic
Rhombencephalon
The rhombencephalon is a developmental categorization of portions of the central nervous system in vertebrates.The rhombencephalon can be subdivided in a variable number of transversal swellings called rhombomeres...
reticular formation
Reticular formation
The reticular formation is a part of the brain that is involved in actions such as awaking/sleeping cycle, and filtering incoming stimuli to discriminate irrelevant background stimuli...
and spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
. These efferent
Efferent
Efferent is an anatomical term with the following meanings:*Conveying away from a center, for example the efferent arterioles conveying blood away from the Bowman's capsule in the kidney. Opposite to afferent....
axons cross just ventral to the anterior tegmental decussation and descend through the midbrain to the spinal cord, where the rubrospinal tract
Rubrospinal tract
The rubrospinal tract is a part of the nervous system. It is a part of the lateral indirect extra-pyramidal tract.-Function:In humans, the rubrospinal tract is one of several major motor control pathways. It is smaller and has fewer axons than the corticospinal tract, suggesting that it is less...
which they make up runs ventral to the lateral corticospinal tract
Lateral corticospinal tract
The lateral corticospinal tract is the largest part of the corticospinal tract...
in the lateral funiculus
Lateral funiculus
The most lateral of the bundles of the anterior nerve roots is generally taken as a dividing line that separates the antero-lateral region into two parts, viz., an anterior funiculus, between the anterior median fissure and the most lateral of the anterior nerve roots; and a lateral funiculus,...
. Second bundle of fibers continues ipsilaterally through the medial tegmental
Tegmentum
The tegmentum is a general area within the brainstem. It is located between the ventricular system and distinctive basal or ventral structures at each level...
field towards inferior olive
Inferior olivary nucleus
The inferior olivary nucleus is the largest nucleus situated in the olivary body, part of the medulla oblongata.-Function:It is closely associated with the cerebellum, meaning that it is involved in control and coordination of movements, sensory processing and cognitive tasks likely by encoding the...
.
External links
- Diagram at Stanford UniversityStanford UniversityThe Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...
- Diagram at uni-tuebingen.de
