Scientists Digitally Reconstruct Part Of A Rat's Brain

2850 Scientists Digitally Reconstruct Part Of A Rat's Brain
A photo of the virtual brain slice, containing around 30,000 individual neurons. Markham/EPFL

Scientists have managed to digitally reconstruct a portion of rat brain, albeit a really small piece. In the first draft of what is possibly one of the most sophisticated neural simulations ever created, researchers have modeled over 30,000 neurons connected by 40 million synapses. They have even been able to alter the inputs into the model and watch how the signals from individual neurons ripple through the simulation.

The monumental effort, resulting from decades of work involving over 80 researchers, has been undertaken by the Blue Brain Project, an ambitious initiative to reverse engineer the rat brain. But the objective doesn’t end there, as sights are set much higher. The Blue Brain Project feeds into a far more complex initiative to recreate the human brain in code. The scientist at the center of both of these projects, Henry Markham, sees these results published in Cell as proof that the Human Brain Project can actually be achieved.


Some scientists have, however, been a little more cautious, and others have been outright damning. Many say that this paper, the first substantial results to be published since the project began back in 2005, is evidence enough that the concept of recreating an entire brain in a computer is simply a waste of money and resources. And with the Human Brain Project being eligible for €1 billion from the European Commission, many warn that it is chronically mismanaged and will divert funding away from other important neurological studies. Last year, hundreds of scientists signed an open letter threatening a boycott of the project.

It is an undoubtedly impressive – and staggeringly beautiful – achievement either way. Firstly, the scientists spent years studying and logging all the different types of neurons found in the brain of rats, and figuring out the rules that govern how they are arranged. Then they built an algorithm that would place up to 30,000 neurons in the correct position, and then locate where each one touched another – a potential site for a connection, or synapse. But this gave them nearly 200 million synapses, much greater than what is expected in a slice of brain this size. They were eventually able to cut this down to a more realistic 37 million connections.

The result is a tiny one-third of a cubic millimeter of rat neocortex recreated in a computer, a long stretch from the human brain that is around 1,130 cubic centimeters with an estimated 86 billion neurons. In addition to that, the simulation only represents around 10% of what actually makes up a brain, as the model does not contain the blood vessels or cells that support the neurons. Markham is quick to point out that this is only a first draft, and that this data will be included in the future. But as one critic told Science: "That’s like saying, 'I want to go to the moon and I have already put a ladder against this tree.'"

Whether it's a colossal waste of time and money, or the first step to creating a digital human brain, Markham is certain that the end results will be worth it. What those end results will be able to show, though, is a little less definite, as the model is apparently being developed with no questions in mind. 


Image in text: A photo of the entire digitally created brain column. Markham/EPFL


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  • brain,

  • computer simulations,

  • rat brain,

  • Human Brain Project