Washington – Thanks to a mouse that saw videos of “The Matrix”, Scientists have created the largest functional map of a brain to date: A wiring diagram that connects 84,000 neurons while sending messages.
Using a piece of the animal’s brain, the size of an poppy seed, the researchers identified those neurons and tracked how they communicated through branched fibers with 500 million unions called synapses.
The huge data set, published on Wednesday by Nature magazine, marks a step towards the unraveling of the mystery of how our brains operates. The data, assembled in a colored 3D reconstruction to delineate different brain circuits, are open to scientists around the world for additional research, and for simply curious who wish to take a look.
“It definitely inspires a feeling of astonishment, as well as looking at images of galaxies,” said Forrest Collman of the Allen Institute for the science of the brain in Seattle, one of the main researchers of the project. “It gives you an idea of how complicated you are. We are looking at a small part … of the brain of a mouse and the beauty and complexity that you can see in these real neurons and the hundreds of millions of connections between them.”
How we think, feel, see, talk and move is due to neurons, or nerve cells, in the brain: how messages are activated and sent. Scientists have long known that these signs move from a neuron along fibers called axons and dendrites, using synapses to jump to the next neuron. But you know less about the networks of neurons that perform certain tasks and how the interruptions of that wiring could play a role in Alzheimer’s, autism or other disorders.
“You can make a thousand hypotheses about how brain cells could do their job, but you can’t try those hypothesis unless you know the most fundamental thing: how those cells are connected,” said the scientist of the Allen Clay Reid Institute, who helped in the first electronic microscopy to study neuronal connections.
With the new project, a world team of more than 150 researchers mapped neuronal connections that Collman compares with tangled spaghetti pieces that serpent through the brain of the mouse responsible for the vision.
The first step: Show a mouse video fragments of science fiction films, sports, animation and nature.
A team from the Baylor Medical College did precisely that, using a mouse designed with a gene that makes their neurons shine when they are active. The researchers used a laser -driven microscope to record how individual cells in the animal’s visual cortex illuminated while processing the images that passed.
Next, the scientists of the Allen Institute analyzed that small piece of brain tissue, using a special tool to cut it into more than 25,000 layers, each much thinner than a human hair. With electronic microscopes, They took almost 100 million high -resolution images of those sectionsilluminating those fibers similar to spaghetti and meticulously re -assembly the data in 3D.
Finally, Princeton University scientists used artificial intelligence to track all that wiring and “paint each of the individual cables of a different color so that we can identify them individually,” Collman explained.
They estimated that this microscopic wiring, if extended, would measure more than 3 miles. The important thing is that when all that anatomy with the activity in the mouse brain was related while watching movies, the researchers could track how the circuit worked.
Princeton researchers also created 3D digital copies of the data that other scientists can use to develop new studies.
Could this type of mapping help scientists eventually find treatments for brain diseases? The researchers call it a fundamental step, such as the human genome project that provided the first mapping of genes and eventually led to gene -based treatments. Mapear a complete mouse brain is one of the next goals.
“The technologies developed by this project will give us our first opportunity to really identify some type of abnormal connectivity pattern that gives rise to a disorder,” said another of the main researchers of the project, the neuroscientist and computer scientist at Princeton Sebastian Seung.
The work “marks a great advance and offers an invaluable community resource for future discoveries,” wrote the neuroscientists of Harvard Mariela Petkova and Gregor Schuhknecht, who did not participate in the project.
The huge publicly shared data “will help unravel the complex neural networks underlying cognition and behavior”they added.
The Cortical Network Machine Intelligence Consortium (MICROns) was funded by the Brain Initiative of the National Health Institutes of the United States and Iarpa, the activity of advanced intelligence research projects.