An abacus in our brain

Human beings are visually oriented creatures; we believe what we see and perceive the world in colour and in three dimensions. As many as a quarter of the nerve cells in our cerebral cortex are involved in dealing with stimuli from our eyes.
This is the reason Serge Dumoulin conducts a lot of research into the processing of visual information. But his curiosity has taken him even further: the visual system is a model for the entire cerebral cortex, and he uses this as a laboratory to develop and test new research methods.
One of his most notable findings to date had nothing to do with the eyes. Many animals have an innate “feel” for quantities. Dumoulin discovered that the nerve cells that are involved in this sense or feeling are laid out in a kind of line in the brains of humans: together they form a sort of abacus in our brains.
Such direct spatial representation in the brains was already recognised in relation to other things, for example our limbs, but not for an abstract mathematical concept such as ‘quantity’.
To find answers to new questions, Dumoulin regularly develops new methods for analysing and interpreting brain scans. Some of these have spread like wildfire: all around the world universities are using his software to process their own research data.

Dumoulin: “I examine people’s brains using modern scanning techniques to see how they work. I especially want to know how the brain perceives the world: how are the visual stimuli from the eyes combined with what is already known about the world? Until recently researchers largely looked at the activity of the brain on two levels. On a microscopic scale, neurophysiologists examined individual nerve cells and with scanning techniques such as MRI or PET we are able to bring the entire brain into focus. In between is a level where different types of nerve cells together form ‘computational processing units’. We suspect that a lot of calculations take place in our brains in such units. That means that they are probably the most important building blocks of the brain. But it is precisely at this level that brain researchers cannot observe a great deal, at least not in living subjects. Until now we have had to make do mostly with operations on animals. Thanks to the Ammodo KNAW Award I can now use an ultramodern 7 Tesla MRI scanner, a scanner that works with a very strong magnetic field. With this I hope to bring into clear focus the computational processing units and their calculations in living subjects.”