People with a higher IQ (intelligence quotient) are more likely to have fewer connections between neurons in the outer layer of the brain , according to a recent study published in the journal Nature .
While previous research suggested that bigger brains are in fact smarter, a closer look at the microstructural architecture of our thinking organ suggests that it’s not just about more brain cells, but about a more efficient connection. That is, the reason some people are so smart is because they have fewer neural connections but are much more efficient than others.
Thus, the international team of neurologists used a non-invasive technique known as multilayer diffusion tensor imaging in MRI , to get an idea of the density and ramifications of gray matter within the brains of some 260 male volunteers. and women-.
Each participant in the experiment also took a culturally fair complex reasoning test, producing a variety of scores ranging from 7 to 27 correct answers out of a total of 28 possible.
By piecing together the imaging data with the test scores, the researchers found that those with higher analytical abilities not only had more brain cells, but also tended to have fewer branching between neurons in their cerebral cortex.
They then turned to a database of nearly 500 neural maps within the Human Connectome Project and found the same pattern of higher IQ and lower neural interconnectivity.
At first, it may seem contradictory to us, but it seems that the additional neurons do not transmit more information between them.
In fact, previous research had shown that despite having more neurons to share brain function, smarter brains tend not to work as hard, showing less metabolic activity when subjected to an IQ test, compared with those who ‘struggle’ to obtain high scores.
This observation has led to the development of the neural efficiency hypothesis, which suggests that the analytical power of nerve cell clusters is not trying to push them further, but rather to connect them in a way that minimizes stress. More efficiently.
“Intelligent brains are characterized by a thin but efficient network of neurons. This makes it possible to achieve a high level of thinking with the least possible neuronal activity”, explains neurologist Erhan Genç from Ruhr Bochum University (Germany).
Clearly, the brain is an organ as complicated as it is incredible, and understanding in detail how individual units can interact to solve problems as efficiently as possible could point the way to improving the technology that mimics them.
It may not help us all become geniuses, but it does give us new information about the wiring of the brain at the microstructural level.
Reference: Erhan Genç et al. Diffusion markers of dendritic density and arborization in gray matter predict differences in intelligence, Nature Communications (2018). DOI: 10.1038 / s41467-018-04268-8
