Artistic representation of over 1000 cells from the brain map, each neuron is a different colour
Allen Research Institute
The largest and most comprehensive 3D maps of the mammalian brain to date provide unprecedented insight into neuronal connections and function. A new map capturing cubic millimeters of the mouse visual cortex allows scientists to study brain function in extraordinary detail, revealing important insights into how neural activity shapes behavior, how complex properties like consciousness arise, and even what it means to be human.
“Our behavior ultimately arises from brain activity, and brain tissue shares very similar characteristics across all mammals,” says team members. Forest Colman At the Allen Brain Science Institute in Seattle. “This is one of the reasons why we believe that insights about the mouse cortex can be generalized to humans.”
Results – Biologist Francis Crick said it was “impossible” in 1979 – It took 7 years to complete and engage 150 researchers from three institutions. It began with a team recording neural activity from parts of the mouse’s visual cortex. This wasn’t even bigger than a grain of sand when I saw clips from movies and YouTube.
The second group then analyzed the same brain region, splitting it into 1/400th of the width of human hair, and photographing each slice. The delicate nature of the structure made the team shifted as the slicing process could not be stopped for a long time. “We spent 12 days and 12 nights sectioning this millimeter cube from this organization into almost 30,000 layers,” says team members. Nunoda Costa at Allen Research Institute.
From there, the third team used AI to track all the cells and reconstructed each slice into a 3D map. “It was like asking AI to do the most difficult coloring book in the world,” says Collman. “There are 100 million images in three dimensions, and all cells need to be colored with different crayons. AI needs to stop where one cell starts and the next One.”
This data was ultimately combined with functional activities recorded at the start of the project, allowing what the mice were seeing to link with the corresponding brain activity. The resulting map shows the incredible complexity of the brain. Despite their small size, there were 4 km branches between them, including over 200,000 cells with 523 million synapses connecting the cells.
The data already challenges assumptions about how neurons communicate, revealing that they not only target nearby cells, but also actively oust other cells dedicated to processing the same visual stimuli.
Researchers hope that their maps will bridge some of the knowledge gaps between neural activity and behavior, and ultimately help to unravel complex properties like intelligence. “It’s groundbreaking work that is incredibly valuable to the scientific community.” Natalie Rochefort At the University of Edinburgh, UK.
Da Costa says that beyond its immediate application, it may even be able to test the theory of consciousness. “If someone has a theory of consciousness, they may be able to ask this data question.
The work is based on another study published last year. All neurons in the adult fly brain were mapped – A breakthrough that has already revolutionized the field, says Rochefort. For example, it helped scientists Better understand the circadian rhythms that affect everything From sleep to metabolism.
She says the new map is invaluable and allows researchers to compare it with other maps of different species.
This project has been published in a series Eight papers from natural journals.
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Source: www.newscientist.com