Previous research has suggested that the way in which these folds arise follows a universal law across species, meaning that they all fold in the same way, irrespective of the shape and size of the cortex.
However, it was yet to be determined whether this law also applies to the morphological diversity of different individuals in a single species, in particular with respect to factors, such as age, sex, and disease," note the study authors, led by Dr. Yujiang Wang of Newcastle University in the United Kingdom.
To find out whether folding of the cerebral cortex is universal in humans, Dr. Wang and team used magnetic resonance imaging (MRI) to map the brain folds of more than 1,000 healthy adults.
The results - published in the Proceedings of the National Academy of Sciences - revealed that cortical brain folding in humans does follow a "simple universal law."
However, the team found that as we age, cortical folding changes. Specifically, the researchers found that tension on the inside of the cerebral cortex reduces.
It would be similar to the skin, explains Dr. Wang. As we age, the tension drops and the skin starts to slacken.
The researchers also identified gender differences in cortical folding among men and women of the same age, the cerebral cortex of women showed slightly less folding.