Building Bigger Brains

A distinctive feature of the human brain is its greatly-expanded neocortex, a section of the brain’s outer layer, or cerebral cortex. Its size is thought to be linked to the human-specific gene ARHGAP11B, and to be caused by the proliferation of a particular type of neural progenitor cells, the basal radial glia (bRG). Putting ARHGAP11B into mouse embryos causes an expansion of their neocortex, but mice have too few bRG to adequately investigate their role. By contrast, ferret brains (pictured, with neocortical neurons in green) possess a larger neocortex and more bRG. Introducing ARHGAP11B into ferret embryos leads to greater numbers of bRG, giving rise to neurons for longer during development, and ultimately producing more neurons in the brain’s upper layers. Our uniquely-large neocortex is involved in our most sophisticated cognitive skills, so investigating its developmental origin is one way of exploring the complex biological underpinnings of human intelligence.

Written by Emmanuelle Briolat

Emmanuelle Briolat

Writer

A researcher specialising in visual signals in Lepidoptera, camouflage and the effects of light pollution, Emmanuelle’s writing covers a range of topics, from biomedical research to children’s books about moth defences.

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• Image by Nereo Kalebic and Carlotta Gilardi
• Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
• Image originally published under a Creative Commons Licence (BY 4.0)
• Research published in eLife, November 2018