Brodmann area 10
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Brodmann area 10 (BA10, frontopolar prefrontal cortex, rostrolateral prefrontal cortex, or anterior prefrontal cortex) is the anterior-most portion of the
prefrontal cortex In mammalian brain anatomy, the prefrontal cortex (PFC) covers the front part of the frontal lobe of the cerebral cortex. The PFC contains the Brodmann areas BA8, BA9, BA10, BA11, BA12, BA13, BA14, BA24, BA25, BA32, BA44, BA45, BA46, ...
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 ...
. BA10 was originally defined broadly in terms of its cytoarchitectonic traits as they were observed in the brains of cadavers, but because modern
functional imaging Functional imaging (or physiological imaging) is a medical imaging technique of detecting or measuring changes in metabolism, blood flow, regional chemical composition, and absorption. As opposed to structural imaging, functional imaging center ...
cannot precisely identify these boundaries, the terms anterior prefrontal cortex, rostral prefrontal cortex and frontopolar prefrontal cortex are used to refer to the area in the most anterior part of the frontal cortex that approximately covers BA10—simply to emphasize the fact that BA10 does not include ''all'' parts of the prefrontal cortex. BA10 is the largest cytoarchitectonic area in the human brain. It has been described as "one of the least well understood regions of the human brain". Present research suggests that it is involved in
strategic Strategy (from Greek στρατηγία ''stratēgia'', "art of troop leader; office of general, command, generalship") is a general plan to achieve one or more long-term or overall goals under conditions of uncertainty. In the sense of the "art ...
processes in memory recall and various
executive functions In cognitive science and neuropsychology, executive functions (collectively referred to as executive function and cognitive control) are a set of cognitive processes that are necessary for the cognitive control of behavior: selecting and succe ...
. During
human evolution Human evolution is the evolutionary process within the history of primates that led to the emergence of ''Homo sapiens'' as a distinct species of the hominid family, which includes the great apes. This process involved the gradual development of ...
, the functions in this area resulted in its expansion relative to the rest of the brain.


Anatomy


Size

The volume of the human BA10 is about 14 cm3 and constitutes roughly 1.2% of total brain volume. This is twice what would be expected in a
hominoid Apes (collectively Hominoidea ) are a clade of Old World simians native to sub-Saharan Africa and Southeast Asia (though they were more widespread in Africa, most of Asia, and as well as Europe in prehistory), which together with its sister g ...
with a human-sized brain. By comparison, the volume of BA10 in
bonobo The bonobo (; ''Pan paniscus''), also historically called the pygmy chimpanzee and less often the dwarf chimpanzee or gracile chimpanzee, is an endangered great ape and one of the two species making up the genus '' Pan,'' the other being the comm ...
s is about 2.8 cm3, and makes up only 0.74% of its brain volume. In each hemisphere, area 10 contains an estimated 250 million neurons.


Location

BA10 is a subdivision of the cytoarchitecturally defined frontal region of cerebral cortex. It occupies the most rostral portions of the
superior frontal gyrus In neuroanatomy, the superior frontal gyrus (SFG, also marginal gyrus) is a gyrus – a ridge on the brain's cerebral cortex – which makes up about one third of the frontal lobe. It is bounded laterally by the superior frontal sulcus. The su ...
and the
middle frontal gyrus The middle frontal gyrus makes up about one-third of the frontal lobe of the human brain. (A ''gyrus'' is one of the prominent "bumps" or "ridges" on the surface of the human brain.) The middle frontal gyrus, like the inferior frontal gyrus an ...
. In humans, on the medial aspect of the hemisphere it is bounded ventrally by the superior rostral sulcus. It does not extend as far as 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 ...
. Cytoarchitecturally it is bounded dorsally by the granular frontal area 9, caudally by the middle frontal area 46, and ventrally by the orbital area 47 and by the
rostral area 12 Brodmann area 12 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. It occupies the most rostral portion of the frontal lobe. Brodmann-1909 did not regard it as homologous, either topographically or cy ...
or, in an early version of Brodmann's cortical map (Brodmann-1909), the prefrontal
Brodmann area 11 Brodmann area 11 is one of Korbinian Brodmann, Brodmann's Cell biology, cytologically defined Brodmann area, regions of the brain. It is in the orbitofrontal cortex which is above the orbit (anatomy), eye sockets (orbitae). It is involved in decis ...
-1909. Area 10 lies underneath the air filled
frontal sinus The frontal sinuses are one of the four pairs of paranasal sinuses that are situated behind the brow ridges. Sinuses are mucosa-lined airspaces within the bones of the face and skull. Each opens into the anterior part of the corresponding middle na ...
of the skull, which has limited
electrophysiology Electrophysiology (from Greek , ''ēlektron'', "amber" etymology of "electron"">Electron#Etymology">etymology of "electron" , ''physis'', "nature, origin"; and , '' -logia'') is the branch of physiology that studies the electrical properties of b ...
research until 2009.


Relation to frontal pole

In humans the frontal pole area of the prefrontal cortex includes not only area 10 but part of BA 9. BA 10 also extends beyond the pole area into its ventromedial side. In
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 ...
monkeys, the pole area is filled by BA 12 (and its BA 10 is found in the orbital prefrontal region).


Cytoarchitecture

In humans the six cortical layers of area 10 have been described as having a "remarkably homogeneous appearance". All of them are readily identified. Relative to each other, layer I is thin to medium in width making up 11% of the depth of area 10. Layer II is thin and contains small granular and pyramidal medium to dark staining cells (in terms of Nissl staining) which colors
RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...
and DNA. The widest layer is III. Its pyramidal neurons are smaller nearer the above layer II than the below layer IV. Like layer II its cells are medium to dark. Layers II and III make up 43% of the cortex depth. Layer IV has clear borders with layers III above and V below and it is thin. Its cells are pale to medium in staining. Layer V is wide and contains two distinct sublayers, Va and Vb. The density of cells Va is greater than in Vb and have darker staining. Layers IV and V make up 40% of cortical thickness. Layer VI below layer V and above the white matter contains dark pyramidal and fusiform neurons. It contributes 6% of area 10 thickness. Area 10 differs from the adjacent Brodmann 9 in that the latter has a more distinct layer Vb and more prominent layer II. Neighbouring Brodmann area 11 compared to area 10 has a thinner layer IV with more prominent layers Va, Vb and II. Area 10 in humans has the lowest neuron density among primate brains. It is also unusual in that its neurons have particularly extensive
dendritic Dendrite derives from the Greek word "dendron" meaning ( "tree-like"), and may refer to: Biology *Dendrite, a branched projection of a neuron *Dendrite (non-neuronal), branching projections of certain skin cells and immune cells Physical * Dendr ...
arborization and are highly dense with
dendritic spines A dendritic spine (or spine) is a small membranous protrusion from a neuron's dendrite that typically receives input from a single axon at the synapse. Dendritic spines serve as a storage site for synaptic strength and help transmit electrical si ...
. This situation has been suggested to enable integration of inputs from multiple areas.


Subareas

BA 10 is divided into three sub-areas, 10p, 10m and 10r. 10p occupies the frontal pole while the other two cover the ventromedial part of the prefrontal cortex. Area 10m has thin layers II and IV and a more prominent layer V. In contrast, area 10r has a prominent layer II and a thicker layer IV. Large pyramidal cells are also present in 10r layer III and even more so in area 10p. But it is noted that the "differences between the three areas are gradual, however, and it is difficult to draw sharp boundaries between them". Medial frontopolar (Area 10m) cortex also contains fewer parvalbumin- and calbindin-immunoreactive neurons relative to other frontal lobe regions, especially Area 14 in orbitofrontal cortex and Area 46 in PFC.


Connections

Research upon primates suggests that area 10 has inputs and output connections with other higher-order association cortex areas particularly in the prefrontal cortex while having few with primary sensory or motor areas. Its connections through the
extreme capsule The extreme capsule (Latin: capsula extrema) is a series of nerve tracts between the claustrum and the insular cortex. It is also described as a thin capsule of white matter as association fibres. The extreme capsule is separated from the external ...
link it to the auditory and multisensory areas of the
superior temporal sulcus The superior temporal sulcus (STS) is the sulcus separating the superior temporal gyrus from the middle temporal gyrus in the temporal lobe of the brain. A sulcus (plural sulci) is a deep groove that curves into the largest part of the brain, ...
. They also continue in the
medial longitudinal fasciculus The medial longitudinal fasciculus (MLF) is an area of crossed over tracts, on each side of the brainstem. These bundles of axons are situated near the midline of the brainstem. They are made up of both ascending and descending fibers that ari ...
in the white matter of the superior temporal gyrus areas on the superior temporal gyrus (areas TAa, TS2, and TS3) and nearby multisensory areas on the upper bank of the superior temporal sulcus (TPO). Another area connected through the extreme capsule is the ventral region of the insula. Connections through the cingulate fasciculus link area 10 to the
anterior Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
,
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 ...
, and
retrosplenial cortex 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 ...
. The
uncinate fasciculus The uncinate fasciculus is a white matter association tract in the human brain that connects parts of the limbic system such as the temporal pole, anterior parahippocampus, and amygdala in the temporal lobe with inferior portions of the frontal l ...
connects it with the
amygdala The amygdala (; plural: amygdalae or amygdalas; also '; Latin from Greek, , ', 'almond', 'tonsil') is one of two almond-shaped clusters of nuclei located deep and medially within the temporal lobes of the brain's cerebrum in complex verteb ...
, temporopolar
proisocortex Proisocortex or pro-isocortex is one of two subtypes of cortical areas in the areas belonging to the neocortex. The other subtype is termed the true isocortex. Proisocortical areas are transitional areas placed between areas of true isocortex and ...
and anterior most part of the superior temporal gyrus. There are no connections to the
parietal cortex The parietal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus. The parietal lobe integrates sensory informa ...
,
occipital cortex The occipital lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The name derives from its position at the back of the head, from the Latin ''ob'', "behind", and ''caput'', "head". The occipital lobe is the vi ...
nor
inferotemporal cortex The inferior temporal gyrus is one of three gyri of the temporal lobe and is located below the middle temporal gyrus, connected behind with the inferior occipital gyrus; it also extends around the infero-lateral border on to the inferior surface ...
Its connections have been summarized as "it seems not to be interconnected with ‘downstream’ areas in the way that other prefrontal areas are. .. it is the only prefrontal region that is predominantly (and possibly exclusively) interconnected with supramodal cortex in the PFC, anterior temporal cortex and cingulate cortex." It has been proposed that due to this connectivity that it can "play a major role in the highest level of integration of information coming from visual, auditory, and somatic sensory systems to achieve amodal, abstract, conceptual interpretation of the environment .. and may be the anatomical basis for the suggested role of the rostral prefrontal cortex in influencing abstract information processing and the integration of the outcomes of multiple cognitive operations".


Evolution

Katerina Semendeferi and colleagues has suggested that "During hominid evolution, area 10 underwent a couple of .. changes: one involves a considerable increase in overall size, and the other involves a specific increase in connectivity, especially with other higher-order association areas." Cranial endocasts taken from the inside of the skull of ''
Homo floresiensis ''Homo floresiensis'' also known as "Flores Man"; nicknamed "Hobbit") is an extinct species of small archaic human that inhabited the island of Flores, Indonesia, until the arrival of modern humans about 50,000 years ago. The remains of an i ...
'' show an expansion in the frontal polar region suggesting enlargement in its Brodmann's area 10.


Function

Although this region is extensive in humans, its function is poorly understood. Koechlin & Hyafil have proposed that processing of 'cognitive branching' is the core function of the frontopolar cortex. Cognitive branching enables a previously running task to be maintained in a pending state for subsequent retrieval and execution upon completion of the ongoing one. Many of our complex behaviors and mental activities require simultaneous engagement of multiple tasks, and they suggest the anterior prefrontal cortex may perform a domain-general function in these scheduling operations. Thus, the frontopolar cortex shares features with the
central executive Baddeley's model of working memory is a model of human memory proposed by Alan Baddeley and Graham Hitch in 1974, in an attempt to present a more accurate model of primary memory (often referred to as short-term memory). Working memory splits prim ...
in
Baddeley's model of working memory Baddeley's model of working memory is a model of human memory proposed by Alan Baddeley and Graham Hitch in 1974, in an attempt to present a more accurate model of primary memory (often referred to as short-term memory). Working memory splits pri ...
. However, other hypotheses have also been proffered, such as those by Burgess ''et al.''. These also take into consideration the influence of the limbic system, to which the frontopolar cortex is connected through the ventromedial prefrontal cortex. A 2006 meta-analysis found that the rostral prefrontal cortex was involved in working memory, episodic memory and multiple-task coordination. This area has also been implicated in decision making prior to the decision being available to conscious awareness Soon, Brass, Heinze and Haynes, 2008. Nature Neuroscience


Images

File:Brodmann area 10 animation small.gif, Animation. File:Brodmann area 10 frontal.jpg, front view. File:Brodmann area 10 lateral.jpg, Lateral view. File:Brodmann area 10 medial.jpg, Medial view.


See also

*
Brodmann area A Brodmann area is a region of the cerebral cortex, in the human or other primate brain, defined by its cytoarchitecture, or histological structure and organization of cells. History Brodmann areas were originally defined and numbered by the ...
*
Cytoarchitectonics of the cerebral cortex Cytoarchitecture (Greek '' κύτος''= "cell" + '' ἀρχιτεκτονική''= "architecture"), also known as cytoarchitectonics, is the study of the cellular composition of the central nervous system's tissues under the microscope. Cytoarchi ...
*
List of regions in the human brain The human brain anatomical regions are ordered following standard neuroanatomy hierarchies. Functional, connective, and developmental regions are listed in parentheses where appropriate. Hindbrain (rhombencephalon) Myelencephalon * Med ...
*
Prefrontal cortex In mammalian brain anatomy, the prefrontal cortex (PFC) covers the front part of the frontal lobe of the cerebral cortex. The PFC contains the Brodmann areas BA8, BA9, BA10, BA11, BA12, BA13, BA14, BA24, BA25, BA32, BA44, BA45, BA46, ...


References


External links

* - "frontopolar area 10" * - "Brodmann area 10"
Brede Database Brodmann area 10

BrainMaps Area 10 Of Prefrontal Cortex


{{DEFAULTSORT:Brodmann Area 10 10 Frontal lobe