The lamprey is a jawless fish and it has the simplest neural framework of the spinal cord, hindbrain, and midbrain. The lamprey also has a diencephalon and a telencephalon, which has many subdivisions found in mammals. This means all vertebrate brains seem to have these regions. Looking at differences in the brain between the lamprey and mammals can help us find out how different parts of the brain have evolved. 

Studying the Lamprey

This diagram of the main classes of vertebrates represents the different paths of evolution taking place simultaneously and separately. 

University of California, Davis

Comparisons between modern and ancient species can reveal important information about brain evolution (i.e., general trends of increasing brain size amongst vertebrates over time), including how it may relate to behavior. 

• Endocasts 
• Studying Present-Day Species 

Methods of Measuring Brain Evolution 

Breedlove, S. & Watson, N. (2017). Behavioral neuroscience, eighth edition. Oxford University Press.

Behavioral Neuroscience 8th Edition

A cast of the cranial cavity of a fossil skull that can point to the general size and shape of its brain, but does not offer specific details of it. 

Endocasts

Some modern species' brains still maintain anatomical similarities to those of their ancestors, allowing for more a thorough analysis of these features,  especially of internal structures (i.e., nuclei, fiber tracts, connections between neurons). 

Learn Before

Related

Learn After