Neuroscientists propose a new model for how the brain works. According to this model, it is not the individual brain regions that matter, but their connections. This new view provides a better understanding of how and why brains differ between individuals. The researchers’ paper is published today in a special issue of Science.
Our right hemisphere is for creativity and our left hemisphere for logical thinking. But this idea, which stems from a classical view of how our brains work, is actually an urban myth. According to this view, our brain has several brain regions, each with a specific function. Although this ‘modular’ view of the brain has lost its relevance, it can still be found in many textbooks.
According to Stephanie Forkel, a neuroscientist at Radboud University, and Michel Thiebaut de Schotten, a neuroscientist at the University of Bordeaux, we need to look at how the brain works differently. The functions of the brain are not confined to individual brain regions, but emerge from exchanges between them.
Necessary for speech and reading
“Look at language, for example,” says Forkel. “The result here is more than just the sum of its parts. To communicate, you need to quickly understand what is being said in a certain context and take into account the emotional intentions of the person you are talking to. If the brain worked in a modular fashion, it would not allow us to make all these language-related calculations in such a short time.”
According to neuroscientists, connections can amplify or attenuate brain signals and determine brain structure and function. There is a strong link between the connectivity patterns of brain regions and their activity during cognitive tasks. Based on brain connections, it is possible to predict where in the brain a function will occur. “If you look at a child’s brain before they learn to read and write, you see that the white matter, which is made up of neural pathways, is already connected to the ‘classic’ reading region,” says Forkel.
Brain differences
Another major gap in the classical modular view of the brain is the inability to explain the variation between individuals. “Everyone’s brain is different, and it’s nothing like the textbook brain that we all know. This is something I realized when I was studying the brains of cadavers. Too often in neuroimaging research, participants’ brains are made to fit a standardized brain and the diversity between people is not taken into account. This is now a big issue in neuroscience,” says Stephanie Forkel.
With this new network approach, scientists can model the differences between our brains in the light of evolution, for example. “If you look at white matter, you see that the old parts of our brains (the ‘reptilian’ brain) are more or less the same. The more recently evolved parts show more variability between people. This puts the evolution of the brain in a new context.”
