Cerebral Cortex

The cerebral cortex is an outer layer of tissue organized into two cerebral hemispheres and composed of four distinct lobes.

The cerebral cortex is the thin layer of the brain that covers the outer portion (1.5mm to 5mm) of the cerebrum. It is covered by the meninges and often referred to as gray matter. The cortex is gray because nerves in this area lack the insulation that makes most other parts of the brain appear to be white.

Brodman Areas

One of the pioneers in the study of brain anatomy, Korbinian Brodmann (1868-1918) classified the cerebral cortex into 52 sections, known as Brodmann Areas

Brodmann areas are a system to divide the cerebral cortex according to cytoarchitectural organization, and are, despite controversy, still very widely used as a standardized nomenclature which is superimposed on the somewhat variable gyral and sulcal anatomy.

The classification relies on the fact that the human cortex is composed of six cellular layers, the density and architecture of which vary from region to region. These patterns are visible under the light microscope

They are numbered sequentially, although some regions have been subsequently subdivided and other are only present in non-human primates.

The list below states how areas relate to functional areas and/or gyral landmarks.

Brodmann areas 1, 2 & 3: primary somatosensory cortex (postcentral gyrus)

Brodmann area 4: primary motor cortex (precentral gyrus)

Brodmann area 5: somatosensory association cortex (superior parietal lobule)

Brodmann area 6: premotor cortex and supplementary motor cortex

Brodmann area 7: visuo-motor coordination (superior parietal lobule)

Brodmann area 8: frontal eye fields

Brodmann area 9: dorsolateral prefrontal cortex

Brodmann area 10: anterior prefrontal cortex

Brodmann area 11 & 12: orbitofrontal area (orbital gyri, gyrus rectus, rostral gyrus and part of superior frontal gyrus)

Brodmann area 13 & 16: insular cortex

Brodmann area 17: primary visual cortex (V1)

Brodmann area 18: secondary visual cortex (V2)

Brodmann area 19: associative visual cortex (V3, V4 & V5)

Brodmann area 20: inferior temporal gyrus

Brodmann area 21: middle temporal gyrus

Brodmann area 22: superior temporal gyrus (including Wernicke area)

Brodmann area 23, 24, 28 to 33: cingulate cortex

Brodmann area 25: subgenual area

Brodmann area 26: ectosplenial portion of the retrosplenial region of the cerebral cortex

Brodmann area 27: piriform cortex

Brodmann area 34: dorsal entorhinal cortex

Brodmann area 35 & 36: perirhinal cortex & ectorhinal area

Brodmann area 37: fusiform gyrus

Brodmann area 38: temporal pole

Brodmann area 39: angular gyrus

Brodmann area 40: supramarginal gyrus

Brodmann area 41 & 42: primary auditory cortex (Heschl gyrus)

Brodmann area 43: primary gustatory cortex

Brodmann area 44: part of Broca area (pars opercularis, part of the inferior frontal gyrus)

Brodmann area 45: part of Broca area (pars triangularis, part of the inferior frontal gyrus)

Brodmann area 46: dorsolateral prefrontal cortex

Brodmann area 47: pars orbitalis, part of the inferior frontal gyrus

Brodmann area 48: retrosubicular area

Brodmann area 52: parainsular area