A team of scientists from the University of Bologna (Germany) has compared two of the most complex systems in nature: the neural network of our brain and the cosmic network of galaxies in the universe . What have they discovered? Which are incredibly similar. And not only as they look if we compare a human neuron with a cluster of galaxies. There is more.
The study, which sought to look beyond the visual similarities between the human brain and the cosmic web (the structure of filaments, nodes and voids that make up galaxies). Do the two have a deeper connection?
A priori, neurons and galaxies are very different systems, but this research, published in the journal Frontiers in Physics , suggests that they are shaped by similar underlying principles. Thus, it is not that our brain is like a universe or that the universe is a brain of titanic proportions, but that its dynamics are similar.
Coincidences
- The average brain has 69 billion neurons.
- For a long time, the estimate of the number of galaxies in the universe was 100 billion, but now it is estimated that it is 20 times higher.
- About 77% of the mass of the brain is water.
- About 70% of the energetic matter content of the universe is dark energy.
Within both systems, only 30% of their masses are made up of galaxies and neurons. In both, the galaxies and neurons are arranged in long filaments or nodes between the filaments. Finally, within both systems, 70% of the mass or energy distribution is made up of components that play an apparently passive role: water in the brain and dark energy in the observable universe.
Between cosmology and neurosurgery
Despite having a scale difference of about 27 orders of magnitude, the human brain and the composition of the cosmic web show similar levels of complexity and self-organization , according to the researchers.
Using the shared characteristics of the two systems, the researchers compared a simulation of the galaxy network with sections of the cerebral cortex and cerebellum.
“We calculated the spectral density of both systems”, says Franco Vazza, leader of the study. “This is a technique that is often used in cosmology to study the spatial distribution of galaxies.” “Our analysis showed that the distribution of fluctuation within the cerebellum neural network on a scale of 1 micrometer to 0.1 millimeters follows the same progression of the distribution of matter in the cosmic network ,” added the expert “but, by of course, on a larger scale that goes from 5 million to 500 million light years. ” The grouping and the number of connections emanating from each node were also strangely similar.
The researchers also calculated some parameters that characterize both the neural network and the cosmic network: the average number of connections in each node and the tendency to group several connections in relevant central nodes within the network: the cosmic network, based on a sample. from 3,800 to 4,700 nodes, it averaged 3.8 to 4.1 connections per node . The human cortex, for a sample of 1,800 to 2,000 nodes, averaged 4.6 to 5.4 connections per node. In addition, both systems showed a tendency to group connections around central nodes.
“Once again, the structural parameters have identified unexpected levels of agreement. Probably, the connectivity within the two networks evolves following similar physical principles, despite the striking and obvious difference between the physical powers that regulate galaxies and neurons ”, adds Alberto Feletti. “These two complex networks show more similarities than those shared between the cosmic network and a galaxy or a neural network and the interior of a neuronal body.”
Both the universe and our brains are still quite mysterious. The standard model of cosmology has many uncertainties, such as what is dark matter and dark energy. And when it comes to the brain, we are constantly discovering and increasing our understanding of how connections are formed and how the neural network as a whole evolves.
How do they have so much in common? We still don’t have an answer for that.
Referencia: F. Vazza et al, The Quantitative Comparison Between the Neuronal Network and the Cosmic Web, Frontiers in Physics (2020). DOI: 10.3389/fphy.2020.525731
