Our brains lose their elasticity as we age, much like our skin, new findings have suggested.
The study from Newcastle University in collaboration with the Federal University of Rio de Janeiro looked at the way the human brain folds, discovering that cortical folding alters with age.
By linking the change in brain folding to the tension on the cerebral cortex, it was discovered that tension on the cortex decreased as people age. The impact was also more noticeable in people with Alzheimer’s disease.
In findings published in the academic journal PNAS, it was found that there are underlying mechanisms affecting brain folding that could be used in order to diagnose brain diseases.
The expansion of the cerebral cortex is the most evident element of mammalian brain evolution and is usually seen alongside rising degrees of folding in the cortical surface, the study explained.
It also found that, in the average adult brain, if the cortex of one side of the brain was unfolded, its surface area would be around 100,000mm2. In previous studies, it was suggested that all brains fold the same way irrespective of size and shape.
Now, these new findings offer systematic research showing that the same rule applies to all humans.
Lead author Dr Yujiang Wang of Newcastle University said: “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.
“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.”
Dr Wang explained that, in people with Alzheimer’s disease, the impact is observed at an earlier age and has a larger effect. He added that the next step will be to see if the changes in folding will be able to spot symptoms of disease.
Is there a difference between male and female brains?
The study also highlighted whether there is a difference between folding in male and female brains, identifying some significant changes.
Between genders, brains are different in size, surface area and the extent of folding. Female brains tend to be slightly less folded than males of the same age. However, it was identified that male and female brains follow the same law.
Individuals with Alzheimer’s disease see significantly different brain folding to those who do not have the condition.
Dr Wang concluded: “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 ageing of the cortex.”