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

midbrain The midbrain or mesencephalon is the forward-most portion of the brainstem and is associated with vision, hearing, motor control, sleep and wakefulness, arousal (alertness), and temperature regulation. The name comes from the Greek ''mesos'', " ...

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

iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...

in at least two different forms:

hemoglobin Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocyt ...

and

ferritin Ferritin is a universal intracellular 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. It is the primary ' ...

. The structure is located in the

tegmentum The tegmentum (from Latin for "covering") is a general area within the brainstem. The tegmentum is the ventral part of the midbrain and the tectum is the dorsal part of the midbrain. It is located between the ventricular system and distinctive ba ...

of the midbrain 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 () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...

without a significant

corticospinal tract The corticospinal tract is a white matter motor pathway starting at the cerebral cortex that terminates on lower motor neurons and interneurons in the spinal cord, controlling movements of the limbs and trunk. There are more than one million neur ...

, gait is mainly controlled by the red nucleus. However, in primates, where the

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 An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...

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 The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder mak ...

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 limb of the body and a type of digit, an organ of manipulation and sensation found in the hands of most of the Tetrapods, so also with humans and other primates. Most land vertebrates have five fingers ( Pentadactyly). Chambers ...

s is not modified by the functioning of the red nucleus but relies on the

. 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, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the sp ...

but, via its parvocellular part, relay information from the

motor cortex The motor cortex is the region of the cerebral cortex believed to be involved in the planning, 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 In anatomy, the olivary bodies or simply olives (Latin ''oliva'' and ''olivae'', singular and plural, respectively) are a pair of prominent oval structures in the medulla oblongata, the lower portion of the brainstem. They contain the olivary nucl ...

, an important relay center in the

medulla Medulla or Medullary may refer to: Science * Medulla oblongata, a part of the brain stem * Renal medulla, a part of the kidney * Adrenal medulla, a part of the adrenal gland * Medulla of ovary, a stroma in the center of the ovary * Medulla of t ...

Input and output

The red nucleus receives many inputs from the cerebellum (

interposed nucleus The interposed nucleus is part of the deep cerebellar complex and is composed of the globose nucleus and the emboliform nucleus. It is located in the roof (dorsal aspect) of the fourth ventricle, lateral to the fastigial nucleus. It receives i ...

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 The inferior olivary nucleus (ION), is a structure found in the medulla oblongata underneath the superior olivary nucleus.Gado, Thomas A. Woolsey; Joseph Hanaway; Mokhtar H. (2003). The brain atlas a visual guide to the human central nervous syste ...

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 The lateral corticospinal tract (also called the crossed pyramidal tract or lateral cerebrospinal fasciculus) is the largest part of the corticospinal tract. It extends throughout the entire length of the spinal cord, and on transverse section appe ...

. 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:Gray710.png, Transverse section through mid-brain. File:Gray712.png, Transverse section of mid-brain at level of superior colliculi. File:Gray717.png, Coronal section of brain immediately in front of pons. File:Human brain frontal (coronal) section description 2.JPG, Human brain frontal (coronal) section File:Weber's syndrome.svg File:Slide11kk.JPG, Red nucleus File:Slide3HOM.JPG, Cerebral peduncle, optic chasm, cerebral aqueduct. Inferior view. Deep dissection. File:Slide2ERV.JPG, Cerebrum. Inferior view.Deep dissection

References

External links

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

Function

Input and output

See also

Additional images

References

External links