Brodmann area 13

Brodmann area 13
Frontal cortex of Sapajus sp. BA13 is shown in the diagram at right (orbital surface).
Identifiers
NeuroNames	hier-1009
NeuroLex ID	Brodmann area 13
FMA	68610
Anatomical terms of neuroanatomy []

Brodmann area 13 is a subdivision of the cerebral cortex as defined on the 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.

Located in the anterior part of the insular cortex, Brodmann area 13 shares with other parts of the insular cortex a wide molecular layer (I) and very wide multiform layer (VI).

The external granular layer (II) is relatively dense. The external lamina pyramidalis externa (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 cells, 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 (VICl), which Brodmann considered a likely extension of layer VI beyond the extreme capsule (VICe) (Brodmann-1905).