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 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 body part involved i ...

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

iron Iron () is a chemical element with symbol Fe (from la, ferrum) 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, right in ...

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 (erythrocyte ...

and ferritin. The structure is located in the tegmentum of the midbrain next to the

substantia nigra The substantia nigra (SN) is a basal ganglia structure located in the midbrain that plays an important role in reward and movement. ''Substantia nigra'' is Latin for "black substance", reflecting the fact that parts of the substantia nigra a ...

and comprises caudal magnocellular and rostral parvocellular components. The red nucleus and substantia nigra are subcortical centers of the

extrapyramidal motor system In anatomy, the extrapyramidal system is a part of the motor system network causing involuntary actions. The system is called ''extrapyramidal'' to distinguish it from the tracts of the motor cortex that reach their targets by traveling through ...

Function

In a

vertebrate Vertebrates () comprise all animal taxon, taxa within the subphylum Vertebrata () (chordates with vertebral column, backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the ...

without a significant corticospinal tract, gait is mainly controlled by the red nucleus. However, in

primates Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter includin ...

, where the corticospinal tract is dominant, the

rubrospinal tract The rubrospinal tract is a part of the nervous system. It is a part of the lateral indirect extra-pyramidal tract. Structure In the midbrain, it originates in the magnocellular red nucleus, crosses to the other side of the midbrain, and descend ...

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 m ...

and upper arm via projections of its magnocellular part. In humans, the red nucleus also has limited control over hands, as the

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 1 ...

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, 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 spin ...

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 The cerebellum (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 or even larger. In humans, the cere ...

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

Input and output

The red nucleus receives many inputs from the

( 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

. *The other output (the rubrospinal projection) goes to the rhombencephalic

reticular formation The reticular formation is a set of interconnected nuclei that are located throughout the brainstem. It is not anatomically well defined, because it includes neurons located in different parts of the brain. The neurons of the reticular formation ...

and

of the ''opposite'' side, making up the

, which runs ventral to the lateral corticospinal tract. As stated earlier, the rubrospinal tract is more important in non-primate species: in

, 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