Thanks to a mouse viewing segments from 'The Matrix,' Scientists have developed the most extensive functional map of a brain so far - an illustration depicting how 84,000 neurons connect as they transmit signals.
With just a tiny portion of the mouse’s brain, roughly the size of a poppy seed, scientists were able to pinpoint these nerve cells and follow their communication pathways across an unexpected 500 million synaptic connections.
The extensive data set, released on Wednesday in the journalNature, represents progress towards solving the puzzle of understanding how our brains work.
The information, presented as a 3D reconstruction with various colors indicating distinct neural pathways, is available globally for further investigation by researchers and accessible to those who are merely interested in exploring it.
"Forrest Collman from the Allen Institute for Brain Science in the US, a key researcher on this project, mentioned that 'it certainly instills a feeling of wonder, much like viewing images of distant galaxies,' " he stated.
You start to realize your intricate nature. We're examining just a small section of a mouse's brain, yet the elegance and complexity evident in these individual neurons along with their hundreds of millions of interconnections are astounding.
The way we think, experience emotions, perceive things, communicate, and behave all stem from neurons, which are specialized nerve cells in our brain—how these cells get triggered and relay signals to one another determines our actions and thoughts.
Scientists have been aware for a long time that these signals travel through neurons via structures known as axons and dendrites, then use synapses to transfer to the following neuron.
However, much remains unknown regarding the neuron networks responsible for specific functions and how disturbances in their connections might contribute to various issues. Alzheimer's , such as autism or other conditions.
In the latest initiative, over 150 scientists from around the world collaborated to chart neuronal pathways within a section of the mouse brain associated with sight. These connections were likened by Collman to strands of spaghetti that have been intricately intertwined.
In what manner did researchers chart the human brain?
Step one involves displaying short clips from science fiction films, sporting events, animated content, and natural scenes featuring a mouse.
Researchers at Baylor College of Medicine in the United States achieved this by employing a genetically modified mouse whose neurons emit light when activated.
The scientists employed a laser-driven microscope to capture footage of individual cells within the creature’s visual cortex lighting up as these cells interpreted the rapidly changing visuals.
Following this, researchers from the Allen Institute examined that tiny section of brain tissue. Using a specialized device, they sliced it into over 25,000 sections and captured almost 100 million high-resolution photographs with electron microscopes. Afterward, they meticulously reconstructed these details into a three-dimensional model.
In conclusion, researchers at Princeton University in the United States employed artificial intelligence (AI) to map out all those connections and “assign a distinct color to each wire so they can be identified separately,” as stated by Collman.
They calculated that if the tiny wires were stretched out, they would be longer than 5 kilometers.
Implications for human health
Could this kind of mapping assist researchers in ultimately discovering cures for neurological disorders?
The researchers refer to it as a fundamental step, similar to how the Human Genome Project, which offered the initial gene map, ultimately resulted in therapies based on genes.
One upcoming objective is to map an entire mouse brain.
"The innovations from this initiative will provide our initial opportunity to genuinely detect certain unusual patterns of connection that lead to disorders," stated Sebastian Seung, a Princeton neuroscientist and computer scientist who is also one of the key investigators for the project.
"signifies a significant step forward and provides an indispensable communal asset for upcoming revelations," noted Harvard neuroscientists Mariela Petkova and Gregor Schuhknecht, who were not part of the initiative.
The extensive and collectively accessible data "will aid in deciphering the intricate neurological networks that underlie thought processes and actions," they noted.