The human brain is one of the most mysterious and most complex structures in nature and we are not even close to fully understanding the way it works. Now, a team of researchers has come to a discovery that could bring one step closer to this goal.
Using complex computer models, the research team from the Blue Brain Project has found that the brain is, in fact, a complex combination of ‘multi-dimensional’ geometrical structures and spaces.
As the director of Blue Brain Project, professor Henry Markram, says, in just a small speck of the brain, there can be found tens of millions of multi-dimensional structures that can go up to eleven dimensions.
“We found a world that we had never imagined,” he explained to Wired. These structures are formed when more neurons connect together to form structures called cliques. The bigger the number of neurons, the higher the dimension of the structure.
In order to understand the function of the complex brain network, you need to try to associate it with some familiar objects in order to understand what it does. “Without it, all you see is a mess of ‘trees’ i.e. neurons firing at what appears to be random patterns,” says Ran Levi from Aberdeen University who is also part of the research team.
“What we did is we took the complex structure of the brain network and mapped it to this universe, thus picking up very precisely defined high dimensional objects that give us a key to understanding structure and function,” he explains.
Using algebraic topology, the team modeled the structures within a virtual brain on a computer after which they carried out experiments on real brain tissue to test and compare the results.
In the presence of a stimulus, the team observed the assembly of progressively higher-dimensional cliques and holes (or cavities) in between the cliques. “The appearance of high-dimensional cavities when the brain is processing information means that neurons in the network react to stimuli in an extremely organized manner,” explained Levi.
“The progression of activity through the brain resembles a multi-dimensional sandcastle that materializes out of the sand and then disintegrates.”
“It is as if the brain reacts to a stimulus by building then razing a tower of multi-dimensional blocks, starting with rods (1D), the planks (2D), then cubes (3D), and then more complex geometries with 4D, 5D, etc.”
However, as professor Cees van Leeuwen, from KU Leuven, Belgium, notes, in terms of space, these structures don’t exceed the limit of the three dimensions – the higher dimensions are outside the realm of physics and are more mathematical.
The research team’s next step is to explore the practical roles that these structures play in the brain. This discovery could lead to unraveling the mystery of where the brain stores its memories.
Markram speculates that the higher-dimensional cavities could, in fact, be the storing place of memories.