Brodmann area 45
Encyclopedia
Brodmann area 45 is part of the frontal
cortex
in the human brain
. Situated on the lateral surface, inferior to BA9
and adjacent to BA46
.
This area is also known as pars triangular (of the inferior frontal gyrus). In the human, it occupies the triangular part of inferior frontal gyrus
(H) and, surrounding the anterior horizontal limb of lateral sulcus
(H), a portion of the orbital part of inferior frontal gyrus (H). Bounded caudally by the anterior ascending limb of lateral sulcus (H), it borders on the insula
in the depth of the lateral sulcus.
Cytoarchitectonically it is bounded caudally by the opercular area 44
(BA44), rostrodorsally by the middle frontal area 46
(BA46) and ventrally by the orbital area 47
(BA47) (Brodmann-1909).
, a region which is active in semantic
tasks, such as semantic decision tasks (determining whether a word represents an abstract or a concrete entity) and generation tasks (generating a verb
associated with a noun
).
The precise role of BA45 in semantic tasks remains controversial. For some researchers, its role would be to subserve semantic retrieval or semantic working memory processes. Under this view, BA44 and BA45 would together guide recovery of semantic information and evaluate the recovered information with regards to the criterion appropriate to a given context. A slightly modified account of this view is that activation of BA45 is needed only under controlled semantic retrieval, when strong stimulus-stimulus associations are absent. For other researchers, BA45's role is not restricted to semantics per se, but to all activities which require task-relevant representations from among competing representations.
Frontal lobe
The frontal lobe is an area in the brain of humans and other mammals, located at the front of each cerebral hemisphere and positioned anterior to the parietal lobe and superior and anterior to the temporal lobes...
cortex
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...
in the human brain
Human brain
The human brain has the same general structure as the brains of other mammals, but is over three times larger than the brain of a typical mammal with an equivalent body size. Estimates for the number of neurons in the human brain range from 80 to 120 billion...
. Situated on the lateral surface, inferior to BA9
Brodmann area 9
-Human:Brodmann area 9, or BA9, is part of the frontal cortex in the human brain. It contributes to the dorsolateral prefrontal cortex.-Guenon:The term Brodmann area 9 refers to a cytoarchitecturally defined portion of the frontal lobe of the guenon...
and adjacent to BA46
Brodmann area 46
Brodmann area 46, or BA46, is part of the frontal cortex in the human brain. It is between BA10 and BA45.BA46 is known as middle frontal area 46. In the human brain it occupies approximately the middle third of the middle frontal gyrus and the most rostral portion of the inferior frontal gyrus...
.
This area is also known as pars triangular (of the inferior frontal gyrus). In the human, it occupies the triangular part of inferior frontal gyrus
Inferior frontal gyrus
The inferior frontal gyrus is a gyrus of the frontal lobe . It is labelled gyrus frontalis inferior, its Latin name...
(H) and, surrounding the anterior horizontal limb of lateral sulcus
Lateral sulcus
-External links:* * * http://www.uams.edu/radiology/education/residency/diagnostic/pdf/sylvian_cistern_RSNA2003.pdf...
(H), a portion of the orbital part of inferior frontal gyrus (H). Bounded caudally by the anterior ascending limb of lateral sulcus (H), it borders on the insula
Insular cortex
In each hemisphere of the mammalian brain the insular cortex is a portion of the cerebral cortex folded deep within the lateral sulcus between the temporal lobe and the frontal lobe. The cortical area overlying it towards the lateral surface of the brain is the operculum...
in the depth of the lateral sulcus.
Cytoarchitectonically it is bounded caudally by the opercular area 44
Brodmann area 44
Brodmann area 44, or BA44, is part of the frontal cortex in the human brain. Situated just anterior to premotor cortex and on the lateral surface, inferior to BA9....
(BA44), rostrodorsally by the middle frontal area 46
Brodmann area 46
Brodmann area 46, or BA46, is part of the frontal cortex in the human brain. It is between BA10 and BA45.BA46 is known as middle frontal area 46. In the human brain it occupies approximately the middle third of the middle frontal gyrus and the most rostral portion of the inferior frontal gyrus...
(BA46) and ventrally by the orbital area 47
Brodmann area 47
Brodmann area 47, or BA47, is part of the frontal cortex in the human brain. Curving from the lateral surface of the frontal lobe into the ventral frontal cortex. It is below areas BA10 and BA45, and beside BA11....
(BA47) (Brodmann-1909).
Functions
Together with BA 44 it comprises Broca's areaBroca's area
Broca's area is a region of the hominid brain with functions linked to speech production.The production of language has been linked to the Broca’s area since Pierre Paul Broca reported impairments in two patients. They had lost the ability to speak after injury to the posterior inferior frontal...
, a region which is active in semantic
Semantics
Semantics is the study of meaning. It focuses on the relation between signifiers, such as words, phrases, signs and symbols, and what they stand for, their denotata....
tasks, such as semantic decision tasks (determining whether a word represents an abstract or a concrete entity) and generation tasks (generating a verb
Verb
A verb, from the Latin verbum meaning word, is a word that in syntax conveys an action , or a state of being . In the usual description of English, the basic form, with or without the particle to, is the infinitive...
associated with a noun
Noun
In linguistics, a noun is a member of a large, open lexical category whose members can occur as the main word in the subject of a clause, the object of a verb, or the object of a preposition .Lexical categories are defined in terms of how their members combine with other kinds of...
).
The precise role of BA45 in semantic tasks remains controversial. For some researchers, its role would be to subserve semantic retrieval or semantic working memory processes. Under this view, BA44 and BA45 would together guide recovery of semantic information and evaluate the recovered information with regards to the criterion appropriate to a given context. A slightly modified account of this view is that activation of BA45 is needed only under controlled semantic retrieval, when strong stimulus-stimulus associations are absent. For other researchers, BA45's role is not restricted to semantics per se, but to all activities which require task-relevant representations from among competing representations.