Evolutionary Development of Neural Systems in Vertebrates and Beyond

Abstract

The emerging field of “neuro-evo-devo” is beginning to reveal how the molecular and neural substrates that underlie brain function are based on variations in evolutionarily ancient and conserved neurochemical and neural circuit themes. Comparative work across bilaterians is reviewed to highlight how early neural patterning specifies modularity of the embryonic brain, which lays a foundation on which manipulation of neurogenesis creates adjustments in brain size. Small variation within these developmental mechanisms contributes to the evolution of brain diversity. Comparing the specification and spatial distribution of neural phenotypes across bilaterians has also suggested some major brain evolution trends, although much more work on profiling neural connections with neurochemical specificity across a wide diversity of organisms is needed. These comparative approaches investigating the evolution of brain form and function hold great promise for facilitating a mechanistic understanding of how variation in brain morphology, neural phenotypes, and neural networks influences brain function and behavioral diversity across organisms.

Keywords::

• behavior
• brain development
• brain evolution
• evo-devo
• neuroanatomy

ACKNOWLEDGMENTS

The author thanks Hans Hofmann and Steve Phelps for their mentorship, Luke McGowan for helpful discussions, and Adam Dewan and Deena Walker for thoughtful comments on the manuscript.

Declaration of interest: The author reports no conflicts of interest. The author alone is responsible for the content and writing of the paper.

L.A.O. is supported by the NIGMS National Centers for Systems Biology grant 5P50GM068763.