Cerebrum

from ancient Greek: tele (τῆλε) - distant, egkephalos (ἐγκέφαλος) - brain
Synonym: telencephalon
German: Großhirn

1 Definition

The cerebrum forms the largest part of the human brain and is the most sophisticated structure of the central nervous system. It is responsible for many thought and action processes that differentiate humans from other living beings.

2 External structure

The cerebrum cranially borders the calvarium (skullcap) and caudally sits in the anterior and middle cranial fossa. The interhemispheric fissure (longitudinal fissure) separates the two hemispheres of the brain. The hemispheres can further be divided into four lobes each that are named for the cranial bones that they lie beneath:

• Frontal lobe (lobus frontalis)
• Parietal lobe (lobus parietalis)
• Temporal lobe (lobus temporalis)
• Occipital lobe (lobus occipitalis)

The surface of the cerebrum is deeply grooved which increases surface area. The most prominent of the resulting furrows (sulci) and ridges (gyri) that can be seen from the outside are:

• Central sulcus (central fold) which separates the frontal from the parietal lobe
• Lateral sulcus which separates the frontal and parietal lobe from the temporal lobe.

3 Internal structure

3.1 Cerebral cortex (cortex cerebri), gray matter

The cerebral cortex can be divided into three segments that developed at different evolutionary (phylogenetic) stages:

• Paleocortex
• Archicortex
• Neocortex

Histologically, two parts can be distinguished that each consist of multiple layers:

• Allocortex (hippocampal formation), from outside to inside:
  • Molecular layer (lamina molecularis)
  • Layer of pyramid cells (lamina pyramidalis)
  • A polymorphic layer (lamina multiformis)

• Isocortex, from outside to inside:
  • Molecular layer (lamina molecularis)
  • External granular layer (lamina granularis externa)
  • External pyramidal layer (lamina pyramidalis externa)
  • Internal granular layer (lamina granularis interna)
  • Internal pyramidal layer (lamina pyramidalis interna)
  • A polymorphic layer (lamina multiformis)

Also according to histological features, the cerebral cortex was divided into 52 so-called Brodmann areas by German anatomist Korbinian Brodmann.

3.2 Underlying white matter

The white matter underlying the cortex mainly contains nerve tracts.

3.3 Basal ganglia

The basal ganglia (cerebral nuclei) consist of:

• Striatum, which can be subdivided into:
  • Caudate nucleus
  • Putamen
• Globus pallidus (dorsal pallidium)

4 Histology

How do you like our new histology feature? Tell us what you think!

5 Internet resources

• Atlas of the human brain