Over the last century, almost every medical breakthrough has been based on animal research. But mice may soon get a break from the lab. Researchers from the Human Brain Project have taken the first steps to building a virtual mouse for experiments.
The digital model maps out how a mouse brain connects to a mouse body, using 200,000 virtual neurons. “If you touch the whiskers, we can see the respective signal in the brain,” says neurorobotics scientist Marc-Oliver Gewaltig.
There’s a long way to go before the model is an exact replica of a living mouse, which has 75 million neurons. But as new data comes in, the researchers will continue to fill in the model. Gewaltig compares it to building the first globe in the 15th century by patching together the maps that were available at the time.
“The difficulty is combining different sets of data,” he says. “The data comes from different animals, and there’s variability, so it’s difficult to align one brain with another brain. In this way, it’s more difficult than mapping out the globe, where you can always go to the same location with coordinates.”
Eventually, once the model is fully ready for use, it will have advantages that go beyond saving the lives of animals in the lab. “You can make experiments that would otherwise be difficult to do in a real animal,” says Gewaltig. “The advantage of a simulation is that you literally have access to everything that you put in. You can look at every neuron, every connection, and this is something that you can’t do in an experiment. You can see more.”
Ultimately, the same type of modeling can be used to map out models of other animals–even humans, though the human brain poses certain bigger challenges.
“A human brain is about 1,000 times larger in terms of number of neurons than a mouse brain,” Gewaltig says. “And in terms of the connections, it’s a factor of a million at least.” That means current computers aren’t powerful enough to crunch the data. And because humans haven’t been researched on like mice, there isn’t as much data to build a full model. Still, that’s something that the Human Brain Project aims to do.
In the meantime, the virtual mouse may eventually start to save some of the millions of mice used each year to research drugs for everything from cancer and heart attacks to Alzheimer’s disease. The researchers plan to release an early prototype of the mouse in April.