Cerebral cortex

Cerebral cortex

The cerebral cortex is the extensive outer layer of gray matter of the cerebral hemispheres, largely responsible for higher brain functions, including sensation, voluntary muscle movement, thought, reasoning, and memory. The human brain's wrinkled texture results in substantially more cortex than is present in other brains of similar size.

Cerebral cortex is typically 1-4mm thick.

Table of contents

1 Laminar pattern
2 Classification
3 Related topics

Laminar pattern

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

Molecular layer
External granular layer
External pyramidal layer
Internal granular layer
Internal pyramidal layer
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.

Auxilliary 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