Map of 600,000 brain cells rewrites the textbook on how the brain makes decisions
The researchers finished the very first activity card of a mammalian brain in a revolutionary duo of studies, and he rewritten the understanding of scientists of decisions.
The project, involving a dozen laboratories and data of more than 600,000 cerebral cells of individual mouse, has covered areas representing more than 95% of the brain. Research results, published in two papers In the nature of the newspaper,, Suggest that decision -making involves much more brain than we thought before.
The mammoth project was led by the International brain laboratory (IBL), a collaboration of experimental and theoretical neuroscientists from all over Europe and the United States, these scientists were united by a familiar and harassing feeling.
“We had a problem with the way science was over,” said Matteo CalendiniNeuroscientist at the University College of London and the basic member of IBL.
In previous studies on the brain, many separate laboratories have decided to answer major questions about the organ, exploring how brain activity relates to behavior, for example. However, each laboratory studied this question in the brains of different mice and has carried out slightly different behavioral tasks with each set of rodents. Once you have added in the uncertainty about how each research group has defined separate regions in the brain, these inconsistencies have blurred the results.
“We cannot know if we agree or in disagreement, because so much were different,” Carandini told Live Science.
In relation: The most detailed human brain card contains 3,300 types of cells
The IBL therefore met to design a single robust and standardized experience on a scale that no individual laboratory could approach alone. They then associated this megast with precision brain measurement tools and predefined analysis methods to make the results as reproducible as possible. The aim of experience would be to overcome a lasting obstacle in the field.
“One of the oldest challenges in neuroscience is to decipher how the variation in neural systems – both structural and functional – is part of the variation in behavior”, ” Federico TurkheimerA neuroscientist from King’s College London who was not involved in the study, said in a statement in the United Kingdom Science Media Center.
This project finally included 139 mice, spread over 12 laboratories around the world, which were located with brain recording devices called neuropixel probes. Singles can record up to 1,000 individual neurons simultaneously. The researchers tested the mice with a simple behavioral task that each of the dozens of laboratories could reproduce reliably: the researchers placed mice in front of a screen, and a black and white striped marker flashes on the right or on the left. If the mice moved a small wheel in the same direction as the flash, they received a reward.
Based on what you would have read in a neuroscience manual, said Caramini, you expect the brain activity to occur during the experience to follow a linear path. First, the cells of the visual cortex which recognize the images would be triggered, followed by neurons in a different part of the brain, such as the prefrontal cortex, known to be involved in abstract decisions. This information could then be combined with an additional activity which represented the previous experiences of the mouse – in other words, memories – before being sent to the motor regions of the brain which control muscle responses.
The researchers’ results supported part of this chain reaction; The visual cortex was the first thing to activate, for example. However, other results clashed with the team’s expectations.
“We have found decision -making and signals related to previous information in many more brain regions than we could have thought,” said Candini. Overall, activity in almost all regions of the studied brain could be used to deduce whether or not the mouse had received a reward.
In some of the experimental tests, the researchers made the marker on the screen incredibly weak, so that the mice had essentially guess the way to move the wheel. The second article in nature focused on how mice used previous expectations – depending on where the marker had been in previous tests – to inform their assumption. The brain activity that flashed when the mice guessed in these tasks were also much more widely distributed in the brain than the team would not be.
IBL has modeled its approach to understand the brain on similar initiatives, such as the physics of particles carried out at Cern or the Human genome project Work to understand our DNA. To describe the impact of the project, Carandini reaches another area: astronomy.
He noted that the first astronomers could look at the night sky and see all the star, but in very bad detail. With the advent of the telescope, individual celestial bodies could be explored. Previous work in neuroscience, he said, was “as if someone had pointed out a telescope only towards a single galaxy, then different astronomers had pointed their telescopes on different galaxies, and said:” My galaxy does this! “Or” No, my galaxy does that! “The new project, he explained, was like being able to see all the characteristics of the night sky at the same time.
Such work has only been possible with recent technological advances and improved collaboration between laboratories, but Carandini hopes that it can now be used to answer other big questions about the brain. The results of the current document are only correlational, it is therefore not possible to say whether the observed brain activity directly causes a decision or is only associated with the process.
“I think it’s the next border,” he said, “is to add causality to study.”
