In the vastness of the known universe we can admire stars of gargantuan proportions and galaxies that whirl in sidereal space. These universal phenomena can nothing in the presence of the most complex object of the Universe. A study may have unveiled one of the mysteries of the human brain.
The secrets that surround this prodigious organ are multiple and, among them, one of the most studied phenomena concerns the processes of brain folding, mechanisms that lead to the formation of typical ridge-shaped structures.
A biomechanical and computer research team analysed the mechanisms peculiar to the folding, generating simulations and mappings of the brain, in order to understand its complexity and exploit such knowledge to progress in the diagnosis of diseases related to brain development, such as lisscephaly and
Considering the brain’s ecostructure, it can be divided into two layers. The outer part, the cerebral cortex, is made up of grey matter folded and sprayed by blood vessels and dense billions of neurons. The inner portion of the brain is composed of the intricate network of nerve fibers, called myelinized axons.
Scientists have proposed several hypotheses to explain the dynamics of the folding phenomena, although the most accredited by experimental findings remains that known as differential tangential growth.
According to this hypothesis, the outer layer of the brain tends to grow at an accelerated rate compared to the inner one. This dynamic is caused by the processes of development of the neurons themselves and such a difference in growth generates a series of forces of compression on the outer portion of the brain, causing its bending.
To understand the process, one must think of the external layer’s attempt to expand, while the internal layer is blocked, preventing excessive expansion. Given the forces involved and the impossibility for the outer layer to expand beyond a certain limit, the only way to stabilize the structure is to take a folded form, maximizing the surface-volume ratio.
The structure thus constituted allows the development of a greater amount of neurons, packing them efficiently and decreasing the distance between them. It is precisely because of this neuronal density that the perfect biological machine consumes so much energy.
In addition, thanks to the simulations carried out, it has emerged that the same axons seem involved in the regulation of the folding. The ridges tend to form in areas characterized by the high number of axons, while the grooves are located in areas with low density of axons. This suggests the crucial importance of such neuronal structures in brain development.
In case the folding processes follow abnormal trends, pathological conditions such as schizophrenia and loutism are introduced. The more these anomalies are accentuated, the more serious the conditions are.
One of these is known as lisscephaly (smooth brain), a pathology that results in the absence of brain folds and leads to death within 10 years.
At the opposite end of the abnormal spectrum, we find polymicrogyria, a condition in which the outer layer, resulting in thinner, causes a supernumber of folds. Here too, neurological problems, such as seizures, paralysis and brain retardation, are present.
The researchers conclude that, thanks to the development of artificial intelligence, it will be possible to create much more in-depth imaging and mapping models, so as to uncover the secrets hidden in the meandering of our brain.
If you are interested in the most complex organ in nature, here are the eight things you didn’t know about the brain.