The red nucleus or nucleus ruber is a structure in the rostral midbrain involved in

motor coordination In physiology, motor coordination is the orchestrated movement of multiple body parts as required to accomplish intended actions, like walking. This coordination is achieved by adjusting kinematic and kinetic parameters associated with each bo ...

. The red nucleus is pale pink, which is believed to be due to the presence of

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

in at least two different forms:

hemoglobin Hemoglobin (haemoglobin, Hb or Hgb) is a protein containing iron that facilitates the transportation of oxygen in red blood cells. Almost all vertebrates contain hemoglobin, with the sole exception of the fish family Channichthyidae. Hemoglobin ...

and

ferritin Ferritin is a universal intracellular and extracellular protein that stores iron and releases it in a controlled fashion. The protein is produced by almost all living organisms, including archaea, bacteria, algae, higher plants, and animals. ...

. The structure is located in the midbrain tegmentum next to the substantia nigra and comprises caudal magnocellular and rostral parvocellular components. The red nucleus and substantia nigra are subcortical centers of the extrapyramidal motor system.

Function

In a

vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...

without a significant corticospinal tract,

gait Gait is the pattern of Motion (physics), movement of the limb (anatomy), limbs of animals, including Gait (human), humans, during Animal locomotion, locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on s ...

is mainly controlled by the red nucleus. However, in primates, where the corticospinal tract is dominant, the rubrospinal tract may be regarded as vestigial in motor function. Therefore, the red nucleus is less important in primates than in many other mammals. Nevertheless, the crawling of babies is controlled by the red nucleus, as is arm swinging in typical 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 limited control over hands, as the rubrospinal tract is more involved in large muscle movement such as that for the arms (but not for the legs, as the tract terminates in the superior thoracic region of the spinal cord). Fine control of the

finger A finger is a prominent digit (anatomy), digit on the forelimbs of most tetrapod vertebrate animals, especially those with prehensile extremities (i.e. hands) such as humans and other primates. Most tetrapods have five digits (dactyly, pentadact ...

s is not modified by the functioning of the red nucleus but relies on the corticospinal tract. The majority of red nucleus axons do not project to the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

but, via its parvocellular part, relay information from the

motor cortex The motor cortex is the region of the cerebral cortex involved in the planning, motor control, control, and execution of voluntary movements. The motor cortex is an area of the frontal lobe located in the posterior precentral gyrus immediately ...

to the cerebellum through the inferior olivary complex, an important relay center in the medulla.

Input and output

The red nucleus receives many inputs from the cerebellum ( interposed nucleus and the lateral cerebellar nucleus) of the ''opposite'' side and an input from the motor cortex of the ''same'' side. The red nucleus has two sets of efferents: * In humans, the majority of the output goes to the bundle of fibers continues through the medial tegmental field toward the inferior olive of the ''same'' side, to form part of a pathway that ultimately influence the cerebellum. *The other output (the rubrospinal projection) goes to the rhombencephalic reticular formation and

of the ''opposite'' side, making up the rubrospinal tract, which runs ventral to the lateral corticospinal tract. As stated earlier, the rubrospinal tract is more important in non-primate species: in primates, because of the well-developed cerebral cortex, the corticospinal tract has taken over the role of the rubrospinal.

Additional images

File:Gray678.png, Schematic representation of the chief ganglionic categories (I to V). File:Gray690.png, Deep dissection of brain-stem. Ventral view. File:Weber's syndrome.svg File:Slide11kk.JPG, Red nucleus

References

External links

*
Diagram at uni-tuebingen.de
{{Authority control Midbrain Brainstem nuclei

Function

Input and output

See also

Additional images

References

External links