Scientists have successfully shown that the intricate and distinctive twists and turns of the brain are caused by outer growth that occurs quicker then inner brain growth and crumples down on itself.
Simple modeling of the brain folding
Using a two layer gel model of the brain, scientists have recreated the shape of the human brain owing two an expansion in the outer layer of their model once the outer layer was bathed in a solvent solution. The groups findings were recently published in the Journal Nature Physics.
Scientists for years have postulated that the unique brain “shape” occurs owing to biochemical signals that tell the brain to expand and contract. Others have argued that the shape is due to stronger connections in certain areas of the brain.
“There have been several hypotheses, but the challenge has been that they are difficult to test experimentally,” said Tuomas Tallinen, a soft matter physicist at the University of Jyväskylä in Finland who co-authored the research along with Jun Young Chung of Harvard University.
“I think it’s very significant… that we can actually recreate the folding process using this quite simple, physical model.”
Folding in the human brain generally doesn’t occur until around 22 weeks and explains the researchers modeling of a fetal brain.
The researchers used an MRI and recreated the results by creating a mold with a 3D printer after which they filled it with silicon gel. It was after this point where they coated it with a 1mm thick “cortex” and observed the transformation after the introduction of the solvent bath.
Brain folding – Just put it in a jar and add solvent
“When I put the model into the solvent, I knew there should be folding but I never expected that kind of close pattern compared to human brain,” said Dr. Chung.
“It looks like a real brain.”
“In this paper we use real brain geometries, and we reproduce a developmental setting,” Dr Tallinen explained. “We can study how brain geometry affects folding and creates the kind of arrangements of folds that we see in human brains.”
“The things that we saw in our model will inevitably happen in real brains as well, just as a consequence of this simple expansion. But there could be some other biological factors that modulate this process,” he continued noting that there model didn’t negate prior hypothesis that explained brain shapes as a biochemical reaction or strong connections in certain areas.
The researchers plan to continue their work in a hope that its continuation will help others look at conditions caused by the brain’s failure to fold properly.