Brodmann area 13
Encyclopedia
Brodmann area 13 is a subdivision of the cerebral 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...

 as defined on the guenon
Guenon
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"...

 monkey and on the basis of cytoarchitecture. Brodmann area 13 is found in humans, however it seems to act as a bridge between the lateral and medial layers of the brain. Thus it is sometimes misidentified as not being a Brodmann area.

Location

Located in the posterior of the insular cortex
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...

, Brodmann area 13 shares with other parts of the insular cortex
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...

 a wide molecular layer (I) and very wide multiform layer (VI).

Layers

The external 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...

 (II) is relatively dense. The external lamina pyramidalis externa
Lamina pyramidalis externa
Lamina pyramidalis externa is layer 3, or the external pyramidal layer of cortex cerebri....

 (III) has a central stripe of less cellular density that separates two sublayers, IIIa and IIIb. The internal granular layer (IV) is sufficiently wide and dense to separate clearly sublayer IIIb from layer V. The boundary between layers V and VI is defined by larger 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, more pyramidal in shape, in layer V giving way to smaller, more spindle-shaped cells that become denser and more homogeneous deeper in layer VI. Often the spindle cells are arrayed horizontally as in the claustrum
Claustrum
The claustrum, which is suspected to be present in all mammals, is a fairly thin vertical curved sheet of subcortical gray matter...

(VICl), which Brodmann considered a likely extension of layer VI beyond the extreme capsule (VICe) (Brodmann-1905).

External links

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