Brodmann area 6 (BA6) is part of the frontal cortex in the

human brain The human brain is the central organ of the human nervous system, and with the spinal cord makes up the central nervous system. The brain consists of the cerebrum, the brainstem and the cerebellum. It controls most of the activities of the ...

. Situated just anterior to the primary motor cortex ( BA4), it is composed of the

premotor cortex The premotor cortex is an area of the motor cortex lying within the frontal lobe of the brain just anterior to the primary motor cortex. It occupies part of Brodmann's area 6. It has been studied mainly in primates, including monkeys and humans ...

and, medially, the

supplementary motor area The supplementary motor area (SMA) is a part of the motor cortex of primates that contributes to the control of movement. It is located on the midline surface of the hemisphere just in front of (anterior to) the primary motor cortex leg representa ...

(SMA). This large area of the frontal cortex is believed to play a role in planning complex, coordinated movements. Brodmann area 6 is also called agranular frontal area 6 in humans because it lacks an internal granular cortical layer (layer IV). It is a subdivision of the cytoarchitecturally defined precentral region of cerebral cortex. In the human brain, it is located on the portions of the

precentral gyrus The precentral gyrus is a prominent gyrus on the surface of the posterior frontal lobe of the brain. It is the site of the primary motor cortex that in humans is cytoarchitecturally defined as Brodmann area 4. Structure The precentral gyrus li ...

that are not occupied by

Brodmann area 4 Brodmann area 4 refers to the primary motor cortex of the human brain. It is located in the posterior portion of the frontal lobe. Brodmann area 4 is part of the precentral gyrus. The borders of this area are: the precentral sulcus in front ( ...

; furthermore, BA6 extends onto the caudal portions of the superior frontal and middle frontal gyri. It extends from the cingulate sulcus on the medial aspect of the hemisphere to the

lateral sulcus In neuroanatomy, the lateral sulcus (also called Sylvian fissure, after Franciscus Sylvius, or lateral fissure) is one of the most prominent features of the human brain. The lateral sulcus is a deep fissure in each hemisphere that separates th ...

on the lateral aspect. It is bounded rostrally by the granular frontal region and caudally by the gigantopyramidal area 4 (Brodmann, 1909).

In animals

Brodmann area 6 is a cytoarchitecturally defined portion of the frontal lobe of the

guenon The guenons (, ) are Old World monkeys of the genus ''Cercopithecus'' (). Not all members of this genus have the word "guenon" in their common names; also, because of changes in scientific classification, some monkeys in other genera may have co ...

. Brodmann-1909 regarded it as topographically and cytoarchitecturally homologous to the human agranular frontal area 6 and noted that, in the monkey, area 4 is larger than area 6, whereas, in the human, area 6 is larger than area 4. Distinctive features (Brodmann-1905): It is thick relative to other cortical areas; the transition from cortex to subcortical

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

is gradual; cell layers are indistinct; and the internal granular layer (IV) is absent.

Image

File:Brodmann area 6 animation small.gif, Animation. File:Brodmann area 6 frontal.jpg, front view. File:Brodmann area 6 lateral.jpg, Lateral view. File:Brodmann area 6 medial.jpg, Medial view.

References

External links

* – agranular frontal area 6 * – Brodmann area 6 {{Prosencephalon 06 Frontal lobe

In animals

Image

See also

References

External links