Cerebral cortex

The cerebral cortex is the extensive outer layer of gray matter of the cerebral hemispheres, and is involved in higher brain functions, including sensation, voluntary muscle movement, thought, reasoning, and memory. The grooves between the Gyri (known as sulci) on the brain's surface results in much of the cortex being buried; over 60% of the cerebral cortex in primates is buried and not visible from the surface.

Cerebral cortex is typically 2-4mm thick.

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

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 Neocortex that corresponds to isocortex.
• Archicortex
• Microgyrus
• frontal lobe
• temporal lobe
• parietal lobe
• occipital lobe
• limbic lobe
• List of regions in the human brain