Brodmann area 23 (BA23) is a region in the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...

that lies inside the

posterior cingulate cortex The posterior cingulate cortex (PCC) is the caudal part of the cingulate cortex, located posterior to the anterior cingulate cortex. This is the upper part of the "limbic lobe". The cingulate cortex is made up of an area around the midline of the ...

. It lies between

Brodmann area 30 Brodmann area 30, also known as agranular retrolimbic area 30, is a subdivision of the cytoarchitecturally defined retrosplenial region of the cerebral cortex. In the human it is located in the isthmus of cingulate gyrus. Cytoarchitecturally it ...

and

Brodmann area 31 Brodmann area 31, also known as dorsal posterior cingulate area 31, is a subdivision of the cytoarchitecturally defined cingulate region of the cerebral cortex. In the human, it occupies portions of the posterior cingulate gyrus and medial aspe ...

and is located on the medial wall of the

cingulate gyrus The cingulate cortex is a part of the brain situated in the medial aspect of the cerebral cortex. The cingulate cortex includes the entire cingulate gyrus, which lies immediately above the corpus callosum, and the continuation of this in the ci ...

between the

callosal sulcus The corpus callosum (Latin for "tough body"), also callosal commissure, is a wide, thick nerve tract, consisting of a flat bundle of commissural fibers, beneath the cerebral cortex in the brain. The corpus callosum is only found in placental mam ...

and the

cingulate sulcus The cingulate sulcus is a sulcus (brain fold) on the cingulate cortex in the medial wall of the cerebral cortex. The frontal and parietal lobes are separated from the cingulate gyrus by the cingulate sulcus. It terminates as the marginal sulcus o ...

Human

This area is also known as ventral posterior cingulate area 23. It is a subdivision of the cytoarchitecturally defined

cingulate region Cingulata, part of the superorder Xenarthra, is an order of armored New World placental mammals. Dasypodids and chlamyphorids, the armadillos, are the only surviving families in the order. Two groups of cingulates much larger than extant armad ...

cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of ...

. In the human it occupies most of the

posterior cingulate gyrus The posterior cingulate cortex (PCC) is the caudal part of the cingulate cortex, located posterior to the anterior cingulate cortex. This is the upper part of the "limbic lobe". The cingulate cortex is made up of an area around the midline of the ...

adjacent to the

corpus callosum The corpus callosum (Latin for "tough body"), also callosal commissure, is a wide, thick nerve tract, consisting of a flat bundle of commissural fibers, beneath the cerebral cortex in the brain. The corpus callosum is only found in placental mam ...

. At the caudal extreme it is bounded approximately by the

parieto-occipital sulcus In neuroanatomy, the parieto-occipital sulcus (also called the parieto-occipital fissure) is a deep sulcus in the cerebral cortex that marks the boundary between the cuneus and precuneus, and also between the parietal and occipital lobes. Only ...

. Cytoarchitecturally it is bounded dorsally by the

dorsal posterior cingulate area 31 Brodmann area 31, also known as dorsal posterior cingulate area 31, is a subdivision of the cytoarchitecturally defined cingulate region of the cerebral cortex. In the human, it occupies portions of the posterior cingulate gyrus and medial asp ...

, rostrally by the

ventral anterior cingulate area 24 Brodmann area 24 is part of the anterior cingulate in the human brain. Human In the human this area is known as ventral anterior cingulate area 24, and it refers to a subdivision of the cytoarchitecturally defined cingulate cortex region of cere ...

, and ventrorostrally in its caudal half by the

retrosplenial region The retrosplenial cortex (RSC) is a cortical area in the brain comprising Brodmann areas 29 and 30. It is secondary association cortex, making connections with numerous other brain regions. The region's name refers to its anatomical location imm ...

(Brodmann-1909).

Guenon

Brodmann area 23 is a subdivision of the cerebral cortex 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 ...

defined on the basis of cytoarchitecture. Brodmann regarded it as topographically and cytoarchitecturally homologous to the combined ventral posterior cingulate area 23 and dorsal posterior cingulate

of the human (Brodmann-1909). Distinctive Features (Brodmann-1905): the cortex is relatively thin; smaller cells predominate; the cell density of the

multiform layer The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of ...

(VI) is great, producing a distinct boundary with the 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 distribution ...

; the internal granular layer (IV) is rather well developed; the internal

pyramidal layer A pyramid (from el, πυραμίς ') is a structure whose outer surfaces are triangular and converge to a single step at the top, making the shape roughly a pyramid in the geometric sense. The base of a pyramid can be trilateral, quadrilater ...

(V) contains a dense population of round, medium-sized

ganglion cells {{stack, A ganglion cell is a cell found in a ganglion. Examples of ganglion cells include: * Retinal ganglion cell (RGC) found in the ganglion cell layer of the retina * Cells that reside in the adrenal medulla, where they are involved in the s ...

concentrated at the border with layer IV; layers V and VI are narrow with a distinct mutual boundary.

Macaque

In the

macaque The macaques () constitute a genus (''Macaca'') of gregarious Old World monkeys of the subfamily Cercopithecinae. The 23 species of macaques inhabit ranges throughout Asia, North Africa, and (in one instance) Gibraltar. Macaques are principally ...

the researchers Bonin and Bailey describe an area they term LC which is in agreement with Brodmann area 23. The LC area : ''covers the posterior part of the cingulate gyrus and extends into the cingulate sulcus where, on the inferior wall, it is continuous with the frontal cortex FDL''.

Subdivisions

The area has been subdivided further: In the

(

Macaca fascicularis The crab-eating macaque (''Macaca fascicularis''), also known as the long-tailed macaque and referred to as the cynomolgus monkey in laboratories, is a cercopithecine primate native to Southeast Asia. A species of macaque, the crab-eating macaqu ...

) the following subdivisions have been suggested: * 23i (internal) * 23e (external) * 23v (ventral), the most caudalventral (inferior) portion and with most highly developed layer IV. Another suggestion is for

(

Macaca mulatta The rhesus macaque (''Macaca mulatta''), colloquially rhesus monkey, is a species of Old World monkey. There are between six and nine recognised subspecies that are split between two groups, the Chinese-derived and the Indian-derived. Generally b ...

) * 23a, adjacent to the

thus closest to

. * 23b * 23c Further division of 23b is.H. Shibata, M. Yukie, "Differential thalamic connections of the posteroventral and dorsal posterior cingulate gyrus in the monkey". ''

European Journal of Neuroscience The ''European Journal of Neuroscience'' is a biweekly peer-reviewed scientific journal covering all aspects of neuroscience. It was established in 1989 with Ray Guillery (then at the University of Oxford) as the founding editor-in-chief. The ...

''. * pv23b, posteroventral part for 23b, main thalamic projections from anterior nuclei. * d23b, dorsal part of 23b, weak connections from the anterior nuclei.

References

External links