One of the mysteries of the human brain concerns why the surface is wrinkled into ‘ridges’ and ‘trenches’. We covered some of the theories a couple of weeks ago but a new study in the Journal of Biomechanics suggests a completely different take – the rippled surface protects against the effects of head injury.
The research team created a 3D computer model of the brain taken from an MRI brain scan (top) and then generated a second model (bottom) but with the sulci (the ‘trenches’) smoothed out.
They then took each model and simulated a few smacks upside the head from different directions. As well as ‘striking’ the head head on, the researchers also simulated blows causing ‘rotation’.
This is where the brain moves as if it is pivoting around a point. For example, if you look straight on and loll your head from side to side, your brain is following the path of a ‘coronal rotation’. These sorts of blows are known to be a particular cause of tears in the white matter, your brain’s ‘cabling’.
It turns out that a brain with sulci on the surface suffers significantly less strain when the head is struck. And this isn’t just for areas near the surface.
So it seems that having a wrinkly brain may be a good protective measure for when your head has to bounce off a hard surface.