The large debate over how were developed the creases on the brain has finally got to rest. Researchers have concluded that those wrinkles can be explained by physics. Those deep folds were nature’s solution to fitting a large brain into a small skull.
The team reproduced the evolution of the brain from the foetal age by using magnetic resonance images to build a 3D-printed layered gel model of the developing smooth fetal brain, then, they immersed it in a solvent that provoked the outer layers to swell relative to the core, simulating cortical growth.
The simulation showed how the growth put the outer layer into mechanical compression and lead to the creases or wrinkles similar to those in normal brains, according to the published study in Nature.
The experiments did not end there, they also kept proving their conclusion by building a numerical simulation of the brain modelled that started with the same initial geometry, and showed that it could also produced the folded characteristic that was proven before in a realistic developmental course, this time in a computer-base lapse.
Although many previous established determinants control the growing of the cortex, the size, shape, placement and orientation of the folds are due to iterations and variations of an elementary mechanical instability which is caused by the early fetal brain geometry, the authors added.
This means that the brain starts as a clean slave and goes evolving into a larger and more developed brain that was stated by the early established geometry in the fetus. These finding could be an important support to breakthroughs in diagnosing, treating and preventing a range of neurological disorders, thinks Ellen Kuhl from the Stanford University’s department of bioengineering.
Other species have folded brains like chimpanzees, dolphins, elephants and pigs, but the human’s brain in the wrinkliest of them all.
40 years ago scientist from Harvard proposed the physical explanation to the creases, but it was not proven until now by the team from the United States and Europe.
Source: Nature Physics