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Cerebral cortex is typically 2-4mm thick.

1 Laminar pattern

The standard areas of cortex (isocortex) is characterized as having six distinct layers. From outside inward:

1. Molecular layer
2. External granular layer
3. External pyramidal layer
4. Internal granular layer
5. Internal pyramidal layer
6. Fusiform layer

However, there are no actual borders between the layers, and neurons cross layer boundaries with their dendrites and axons trees all over. The pyramidal cells (the majority of the neurons) span at least three layers, and in many cases all the layers. Thus it is not obvious that the layers have any functional significance.

2 Classification

Based on the differencies in lamination the cerebral cortex can be classified into two major groups:

• Isocortex (homotypical cortex), the part of the cortex with six layers.
• Allocortex (heterotypical cortex) with variable number of layers, e.g., olfactory cortex and hippocampus.

Auxiliary classes are:

• Mesocortex , classification between isocortex and allocortex where layers 2, 3 and 4 are merged.
• Proisocortex, Brodmann areas 24 , 25 , 32 .
• Periallocortex is cortical areas adjacent to allocortex .

Based on supposed developmental differencies the following classification also appears:

• Neocortex that corresponds to isocortex.
• Archicortex
• Paleocortex

In addition, cortex may be classified on the basis of gross topographical conventions into the following:

• Temporal Cortex
• Parietal Cortex
• Frontal Cortex
• Occipital Cortex
• Limbic Cortex
• Insular Cortex

3 Related topics

• Microgyrus
• frontal lobeThe frontal lobe is an area in the brains of vertebrates. Located at the front of each cerebral hemisphere, frontal lobes are positioned in front of (anterior to) the parietal lobes. The temporal lobes are located beneath and behind the frontal lobes.
• temporal lobeThe temporal lobe is part of the cerebrum. It lies at the side of the brain, beneath the lateral or Sylvian fissure. Seen in profile, the human brain looks something like a boxing glove. The temporal lobe is where the thumb would be. Behind (posterior to)
• parietal lobeThe parietal lobe is a lobe in the brain. It is positioned above (superior to) the occipital lobe and behind (posterior to) the frontal lobe. Anatomy The central sulcus separates the parietal lobe from the frontal lobe, and the parieto-occipital sulcus se
• occipital lobeThe occipital lobes are the visual processing center of mammalian brains. The primary visual area is Brodmann area 17, located in the interior portion of the occipital lobe at the calcarine sulcus and sometimes continuing onto the surface of the lobe.
• limbic lobe
• List of regions in the human brainHuman brain image constructed from computer scan data Brain brainstem myelencephalon medulla oblongata medullary pyramids metencephalon pons fourth ventricle cerebellum cerebellar vermis cerebellar hemispheres anterior lobe posterior lobe flocculonodular