Identifying The Genes Behind Brain Folding

Gyrification, or brain folding, is a delicate crucial process that characterizes the shape and folds of our brain matter. Although it is well known that brain folding is essential to how healthy brains grow and work, only now have researchers been able to identify the genes linked with the development of both inward and outward folds in the grey matter of the human brain. 

Misfolding has a direct relationship with neurological disorders like anorexia, epilepsy, and autism. The process is also affected by premature birth and fetal growth restriction. While recent data shows that the grey matter in the developing brain expands faster than white matter, creating a mechanical instability that leads to brain folding, previous brain folding studies focused largely on white matter, overlooking gray matter. 

This time, the team of Swiss and Australian researchers focused on sheep brains because of the developmental similarities it shares with the human brain.  The team examined genetic and microstructural differences in future grey matter, the cortical plate, and in the parts of the brain just beneath the "hills" and "valleys" in order to identify patterns in expression. 

 "We found some genes have higher expression in regions that fold outward and lower expression in regions that fold inwards. Other genes reverse this pattern. Together, these genetic expression patterns might explain why the cortical folding pattern is so consistent between individuals of the same species,” says researcher Sebastian Quezada Rojas, lead author of the paper published in Cerebral Cortex.

These results bring scientists closer to fully understanding the science behind brain folding, providing genetic insights as to how and why it happens. "We believe the regions that fold outward and inward are programmed to behave differently, and the shape of the neurons affects the way these areas fold. Untangling these connections will be [the] focus of the next stage of this research," Quezada Rojas says.