First Published in August 2017
Neuronal and galaxy networks are remarkably similar, according to an astrophysicist and neuroscientist team. Both structures are also more alike to each other than either one is to the interior of a neuronal body or the interior of a galaxy, respectively.
Franco Vazza and Alberto Feletti describe the similarities in a recent article on Nautilus, which include:
- The observable universe contains 100 billion galaxies, while the human brain contains about the same number of neurons and non-neuronal cells.
- Visually, a computer simulation of the cosmic web and a cross-section of brain tissue have a similar structure of filaments (neurofilaments or condensed ordinary and dark matter) embedded with bodies (cells or galaxies). The cosmic web consists of all the stars, gas and dark matter in the universe.
- Both networks have similar power spectrum analyses: this measures the fluctuations of a structure, or as the researchers describe: “it tells us how many high-frequency and low-frequency notes make the peculiar spatial melody of each image.”
- The cosmic web and human brain have a similar complexity. This is estimated by measuring the size of the smallest computer program that could predict the behavior of a network. For cosmic networks, this is 1 to 10 petabytes — or million gigabytes — of data. The memory capacity of the human brain is around 2.5 petabytes. In other words, “the entire life experience of a person can also be encoded into the distribution of galaxies in our universe,” write the researchers.
In comparing these two structures, the researchers faced a number of challenges, such as:
- Differing sources of data: telescopes and simulations for galaxy networks; versus electron microscopy, immunohistochemistry, and functional magnetic resonance for neuronal networks.
- Vastly different scales: a neuronal network fits inside your head, but the cosmic web — a structure made up of all of the universe’s galaxies — stretches across tens of billions of light-years.
- While computer simulations of the evolution of the cosmic web have been carried out, none have been performed for the human brain. In lieu of that, the researchers estimated the complexity of the brain based on its intelligence and cognition.
The researchers also found that the power spectra of the cosmic web and the human brain are not fractal. Fractal patterns show up in other complex systems, such as tree branches, clouds and water turbulence. The non-fractal nature of the cosmic web and brain suggests that they may be “scale-dependent, self-organized structures.”
But does this imply something more profound about the nature of these emergent networks? Given the small number of samples and the different measurements required for the cosmic web versus the brain, the researches are hesitant to speculate further.
To understand more, a dynamic analysis of these systems would be needed — this would show how information flows across both spatial scales and time. This type of analysis is already available for the cosmic web, but more sophisticated computer simulations of the brain are needed.
Efforts like these, write the researchers “will help us fill in some of these details and understand whether the universe is even more surprising than we thought.”