Brodmann area 45
Brodmann area 45 (BA45), 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).
Functions
Together with BA 44 it comprises Broca's area, a region which is active in semantic tasks, such as semantic decision tasks (does this word represent an abstract or concrete entity?) and generation tasks (generate a verb associated to 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 [1][2]. 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 [3]. 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 [4].
References
- ^ Gabrieli et al. (1998). "The role of left prefrontal cortex in language and memory". PNAS 95: 906–913.
- ^ Buckner, R. (1996). "Contributions of specific prefrontal brain areas to long-term memory retrieval". Psychonomic Bulletin and Review 3: 149–158.
- ^ Wagner, A. D. (2002). Cognitive control and episodic memory: Contributions from prefrontal cortex. L. R. Squire & D. L. Schacter (Eds.). Neuropsychology of Memory (3rd ed.), pp. 174-192. New York: Guilford Press
- ^ Thompson-Schill et al. (1999). "Effects of repetition and competition on activity of left prefrontal cortex during word generation". Neuron 23: 513–522.
See also
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Brain: telencephalon (cerebrum, cerebral cortex, cerebral hemispheres) |
| Primary sulci/fissures |
Medial longitudinal, Lateral, Central, Parietoöccipital, Calcarine, Cingulate, Callosal Collateral fissure |
| Frontal lobe |
Precentral gyrus (Primary motor cortex, 4), Precentral sulcus, Superior frontal gyrus/Frontal eye fields (6, 8, 9), Middle frontal gyrus (46), Inferior frontal gyrus (44-Pars opercularis, 45-Pars triangularis), Orbitofrontal cortex (10, 11, 12, 47) |
| Parietal lobe |
Somatosensory cortex (Primary (1, 2, 3, 43), Secondary (5)), Precuneus (7m), Parietal lobules (Arcuate fasciculus/Superior (7l), Inferior (40)), Angular gyrus (39), Intraparietal sulcus, Marginal sulcus |
| Occipital lobe |
Primary visual cortex (17), Cuneus, Lingual gyrus, 18, 19 - Lateral occipital sulcus |
| Temporal lobe |
Primary auditory cortex (41, 42), Superior temporal gyrus (38, 22), Middle temporal gyrus (21), Inferior temporal gyrus (20), Fusiform gyrus (37) Medial temporal lobe (Amygdala, Hippocampus, Parahippocampal gyrus (27, 28, 34, 35, 36) |
| Cingulate cortex/gyrus |
Subgenual area (25), anterior cingulate (24, 32, 33), Posterior cingulate (23, 31), Retrosplenial cortex (26, 29, 30), Supracallosal gyrus |
| white matter tracts |
Corpus callosum (Splenium, Genu, Rostrum, Tapetum), Septum pellucidum, Internal capsule, Corona radiata, External capsule, Olfactory tract, Fornix (Commissure of fornix), Anterior commissure, Posterior commissure Terminal stria Superior and Inferior longitudinal fasciculus, uncinate fasciculus, cingulum, Inferior occipitofrontal fasciculus |
| Basal ganglia |
Striatum (Putamen,Caudate nucleus, Nucleus accumbens), Globus pallidus, Claustrum, Subthalamic nucleus, Substantia nigra |
| Other |
Insular cortex Olfactory bulb, Anterior olfactory nucleus Septal nuclei Basal optic nucleus of Meynert |
| Some categorizations are approximations, and some Brodmann areas span gyri. |
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