Human Brains Show More Parallel Traffic Than Animal Brains
In a groundbreaking study comparing the communication networks of human brains with those of macaques and mice, researchers from the Ecole Polytechnique Federale de Lausanne (EPFL) have made a remarkable discovery. The study reveals that only human brains have the ability to transmit information through multiple parallel pathways, shedding new light on mammalian evolution.
Lead author Alessandra Griffa, a senior postdoctoral researcher at EPFL, used travel metaphors to explain brain communication networks. She likened brain signals to roads with multiple stops along the way. While previous research has focused on the structural connectivity pathways of neuronal fibers, Griffa wanted to explore how information is actually transmitted.
To accomplish this, the researchers analyzed open-source diffusion and functional magnetic resonance imaging (fMRI) data from humans, macaques, and mice. They reconstructed brain road maps using the diffusion scans and examined the areas that lit up along each pathway in the fMRI scans, indicating the relay of neural information.
By applying information and graph theory to the multimodal MRI data, the researchers uncovered new insights. They discovered that in non-human brains, information was sent along a single pathway, whereas in human brains, there were multiple parallel pathways between the same source and target. Interestingly, these parallel pathways were as unique as fingerprints and could potentially be used for individual identification.
Griffa explains, Such parallel processing in human brains has been hypothesized, but never observed before at a whole-brain level.
The researchers’ model not only simplifies the understanding of brain communication networks but also opens up new avenues for research in evolution and computational neuroscience. The study suggests that parallel information streams in human brains enable multiple representations of reality and the performance of abstract functions unique to humans.
While these hypotheses require further testing, Griffa anticipates future exploration of computational and cognitive abilities. The researchers aim to investigate whether parallel information transmission may confer resilience to brain networks, potentially playing a role in neurorehabilitation after brain injury or preventing cognitive decline in age-related pathologies.
This study lays the groundwork for investigating the relationship between parallel information streams, cognitive abilities, and neurodegenerative processes, Griffa explains.
The findings have significant implications beyond neuroscience. The expansion of human brain volume over time corresponds to more complex connectivity patterns. Understanding how parallel information processing contributes to human intelligence could provide valuable insights into the evolution of mammalian brains.
The study, titled Evidence for increased parallel information transmission in human brain networks compared to macaques and mice, was published in the journal Nature Communications.
With this breakthrough discovery, scientists now have a clearer understanding of the unique communication networks in the human brain. The research not only contributes to our knowledge of mammalian evolution but also paves the way for future investigations into cognition, neurorehabilitation, and cognitive decline.
