Brodmann area 20
Encyclopedia
Human
Brodmann area 20, or BA20, is part of the temporalTemporal lobe
The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....
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...
. The region encompasses most of the ventral temporal cortex, a region believed to play a part in high-level visual processing and recognition memory.
This area is also known as inferior temporal area 20, and it refers to a subdivision of the cytoarchitecturally defined temporal region of cerebral cortex. In the human it corresponds approximately to the inferior temporal gyrus. Cytoarchitecturally it is bounded medially by the ectorhinal area 36 (H), laterally by the middle temporal area 21, rostrally by the temporopolar area 38 (H) and caudally by the occipitotemporal area 37 (H) (Brodmann-1909).
Guenon
Brodmann area 20 is a subdivision of the cerebral cortex of the guenonGuenon
The guenons are the genus Cercopithecus of Old World monkeys. Not all the members of this genus have the word "guenon" in their common names, and because of changes in scientific classification, some monkeys in other genera may have common names that do include the word "guenon"...
defined on the basis of cytoarchitecture. It is cytoarchitecturally homologous
Homology (biology)
Homology forms the basis of organization for comparative biology. In 1843, Richard Owen defined homology as "the same organ in different animals under every variety of form and function". Organs as different as a bat's wing, a seal's flipper, a cat's paw and a human hand have a common underlying...
to the inferior temporal area 20 of the human (Brodmann-1909). Distinctive features (Brodmann-1905): area 20 is similar to area 19 of Brodmann-1909 in the relative abundance of small cell types relative to the number of larger pyramidal cell
Pyramidal cell
Pyramidal neurons are a type of neuron found in areas of the brain including cerebral cortex, the hippocampus, and in the amygdala. Pyramidal neurons are the primary excitation units of the mammalian prefrontal cortex and the corticospinal tract. Pyramidal neurons were first discovered and...
s; a very dense, wide internal granular layer
Granular layer
The term granular layer may refer to:*the granular layer of Tomes, seen in dentin of the teeth. When dry section of the root dentin of teeth are visualized under transmitted light, a granular layer is seen adjacent to cementum.It is believed to be caused by coalescing & looping of terminal portion...
(IV) composed almost exclusively of granule cell
Granule cell
In neuroscience, granule cells refer to tiny neurons that are around 10 micrometres in diameter. Granule cells are found within the granular layer of the cerebellum , the dentate gyrus of the...
s, as in area 18 of Brodmann-1909; a broad, clear internal pyramidal layer (V) with few cells; and a distinct multiform layer (VI). The major differences from areas 18 and 19 are somewhat lesser cell density; absence of a division of the external pyramidal layer (III) into sublayers 3a and 3b; layer V is more clearly distinguished from layer VI and, on average, has a greater density of pyramidal ganglion cell
Ganglion cell
A retinal ganglion cell is a type of neuron located near the inner surface of the retina of the eye. It receives visual information from photoreceptors via two intermediate neuron types: bipolar cells and amacrine cells...
s than in the other areas; layer VI is wider, more diffuse and has fewer cells that are concentrated in the outer part of the layer to produce a denser sublayer 6a and a less dense sublayer 6b.
External links
- For Neuroanatomy of the inferior temporal area 20 visit BrainInfo
- For Neuroanatomy of Brodmann area 20 visit BrainInfo
See also
- Brodmann areaBrodmann areaA Brodmann area is a region of the cerebral cortex defined based on its cytoarchitectonics, or structure and organization of cells.-History:...
- List of regions in the human brain