Brodmann area 6

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[edit] Human

Brodmann area 6, or BA6, is part of the frontal cortex in the human brain. Situated just anterior to the primary motor cortex (BA4), it is sometimes called the premotor cortex. The medial part of BA6 is also referred to as the supplementary motor area, or SMA. This large area of the frontal cortex is believed to play a role in the planning of complex, coordinated movements.

Brodmann area 6 is also called agranular frontal area 6 in humans because it lacks in 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 which are not occupied by the gigantopyramidal area 4; 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 on the lateral aspect. Cytoarchitecturally it is bounded rostrally by the granular frontal region and caudally by the gigantopyramidal area 4 (Brodmann, 1909).

[edit] Guenon

Brodmann area 6 is a cytoarchitecturally defined portion of the frontal lobe of the guenon. 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, while 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 is gradual; cell layers are indistinct; and the internal granular layer (IV) is absent.

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[edit] See also

Telencephalon (cerebrum, cerebral cortex, cerebral hemispheres) - edit

primary sulci/fissures: medial longitudinal, lateral, central, parietoöccipital, calcarine, cingulate

frontal lobe: precentral gyrus (primary motor cortex, 4), precentral sulcus, superior frontal gyrus (6, 8), middle frontal gyrus (46), inferior frontal gyrus (Broca's area, 44-pars opercularis, 45-pars triangularis), prefrontal cortex (orbitofrontal cortex, 9, 10, 11, 12, 47)

parietal lobe: postcentral sulcus, postcentral gyrus (1, 2, 3, 43), superior parietal lobule (5), inferior parietal lobule (39-angular gyrus, 40), precuneus (7), intraparietal sulcus

occipital lobe: primary visual cortex (17), cuneus, lingual gyrus, 18, 19 (18 and 19 span whole lobe)

temporal lobe: transverse temporal gyrus (41-42-primary auditory cortex), superior temporal gyrus (38, 22-Wernicke's area), middle temporal gyrus (21), inferior temporal gyrus (20), fusiform gyrus (36, 37)

limbic lobe/fornicate gyrus: cingulate cortex/cingulate gyrus, anterior cingulate (24, 32, 33), posterior cingulate (23, 31),
isthmus (26, 29, 30), parahippocampal gyrus (piriform cortex, 25, 27, 35), entorhinal cortex (28, 34)

subcortical/insular cortex: rhinencephalon, olfactory bulb, corpus callosum, lateral ventricles, septum pellucidum, ependyma, internal capsule, corona radiata, external capsule

hippocampal formation: dentate gyrus, hippocampus, subiculum

basal ganglia: striatum (caudate nucleus, putamen), lentiform nucleus (putamen, globus pallidus), claustrum, extreme capsule, amygdala, nucleus accumbens

Some categorizations are approximations, and some Brodmann areas span gyri.