Grey Matter of the Cortex
Korbinian Brodmann described in 1909 areas of the cerebral cortex on the basis of cytoarchitectural criteria. Areas differ in cell-types, layering and cell distribution, resulting in 52 Brodmann Areas.
Examples: Brodmann Area 3,1,2 Primary Somatosensory Cortex S1, Brodmann Area 17 Primary Visual Cortex V1.
Cerebral Convolutions: Species Differences
- Gyrencephalic (Human, Elephant).
- Lissencephalic (Rabbit, Mouse) (No gyrus structures).
Lissencephaly in Humans is due to a defective migration during early to mid-gestation (12^th^ to 24^th^ weeks), leading to impaired development of gyri and sulci.
White Matter: Macroscopic
- Association Fibers (Green) link cortical areas of the same hemisphere. Arcuate fibers run over short distances, long-distance association fibers have names, such as the Superior and Inferior Longitudinal Bundle/Fasciculus, the Cingulum and Uncinate Bundle.
- Commissural Fibers (Red) link areas of the two hemispheres (Corpus Callosum, Anterior Commissure, Posterior Commissure).
- Projecting Fibers (Blue) link the cortex with subcortical areas of the brain and the spinal cord (e.g., Internal Capsule).
White Matter: Microscopic
- Oligodendrocytes
- Microglia
- Astrocytes