Vertebrate brain theory

The endbrain of vertebrates consists of the mostly paired endbrain nuclei and the two endbrain hemispheres as well as numerous fibrous tracts and commissures.

In each hemisphere, the olfactory bulb is located at the anterior end. The corpus striatum, which is part of the basal ganglion system, is located ventrally. In humans it consists of the caudatus nucleus, the putamen and the globus pallidus. On the outside is the cortex, which is formed by four brain lobes: frontal lobe, temporal lobe, parietal lobe and occipital lobe.

The temporal lobe contains the hippocampus. Together with the amygdala, the habenulae and the mammillary bodies, it forms the limbic system.

The structure of the endbrain of reptiles and birds is different from that of mammals.

The endbrain consists of a large number of substructures that were formed at different times in the evolutionary development of vertebrates. A hierarchically structured system can be identified from the signalling pathways. The mammalian cerebral cortex is the most recent development in the long chain of evolutionary developments.