Brains of flies and humans quite similar.

• Position: Arthropods

Decisionmaking centers in the brains of insects and mammals share too many similarities to have evolved independently, according to comparative studies led by Nick Strausfeld, professor of neuroscience at the University of Arizona, Tucson. The findings may help better understand the mechanisms underlying diseases like Parkinson's.

The study reveals the deep similarities in how the brain regulates behavior in arthropods (such as flies and crabs) and vertebrates (such as fish, mice, and humans).The findings shed new light on the evolution of the brain and behavior, and may aid understanding of disease mechanisms underlying mental health problems.

Based on their own findings and available literature, Strausfeld and Frank Hirth of the Institute of Psychiatry at King's College London compared the development and function of the central brain regions--the "central complex" in arthropods and the "basal ganglia" in vertebrates. Research suggests that both brain structures derive from embryonic cells at the base of the developing forebrain and, that, despite the major differences between species, their respective constitutions and specifications derive from similar genetic programs.

"When you compare the two structures, you find that they are very similar in terms of how they're organized," points out Strausfeld. "Their development is orchestrated by a whole suite of genes that are homologous between flies and mice, and the behavioral deficits resulting from disturbances in the two systems are remarkably similar as well."

The authors describe that nerve cells in the central complex and the basal ganglia become interconnected and communicate with each other in similar ways, facilitating the regulation of...