The folding characterising our brain changes with age, says a new study published in the journal Proceedings of the National Academy of Sciences. This change might be linked with Alzheimer’s disease.
Ageing comes hand in hand with unpleasant experiences that youthfulness would never know. We go through a plethora of changes as we age, and our brain is certainly not left out in this downward spiral. Truth is, it’s not just the skin that sags, but the brain too.
A team from UK’s Newcastle University working in collaboration with Brazil’s Federal University spotted modifications in brain folding (cortical folding) with age.
“One of the key features of a mammalian brain is the grooves and folds all over the surface— a bit like a walnut —but until now no-one has been able to measure this folding in a consistent way,” says Dr Yujiang Wang, who thus set out to find out.
This change was then linked with a decreasing tension in a region of the brain called the cerebral cortex.
“By mapping the brain folding of over 1,000 people, we have shown that our brains fold according to a simple universal law. We also show that a parameter of the law, which is interpreted as the tension on the inside of the cortex, decreases with age,” says Dr Wang.
Cortical folding is said to be the same in mammals, irrespective of size and shape. It, thus, follows a universal law. The same law has been shown to apply within a species in the new study: Dr Wang explains that their findings demonstrate that this law can be used to study changes in the human brain.
“From this, we identified a parameter that decreases with age, which we interpret as changing the tension on the cortical surface. It would be similar to the skin. As we age, the tension drops and the skin starts to slacken,” says Dr Wang.
“It has long been known that the size and thickness of the cortex changes with age but the existence of a general law for folding shows us how to combine these quantities into a single measure of folding that can then be compared between genders, age groups and disease states.”
Cortical folding changes in the same manner in both males and females. However, male and female brains are of different sizes, surface areas, and degrees of folding. While the same law is maintained for both, the female brain is less folded than that of its counterpart.
“This indicates that for the first time, we have a consistent way of quantifying cortical folding in humans,” says Dr Wang.
The findings also show that the change in brain folding is significantly different for patients of Alzheimer’s disease.
She adds: “More work is needed in this area but it does suggest that the effect Alzheimer’s disease has on the folding of the brain is akin to premature aging of the cortex.”
Alzheimer’s patients are known to have a greater decrease in the tension in the cerebral cortex.
“In Alzheimer’s disease, this effect is observed at an earlier age and is more pronounced. The next step will be to see if there is a way to use the changes in folding as an early indicator of disease.”