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The analogy doesn’t work, says Adrienne Fairhall, a neuroscientist from the University of Washington who has a background in physics. Yes, large-scale simulations are useful for understanding weather and galaxies, but “planetary systems are not about anything other than themselves,” she says. “A brain is built to be about other things.” That is: It takes in information about the world, and it moves human and animal bodies, which then influence that world. How much would we really learn from a disembodied brain in a virtual jar, which isn’t connected to eyes, ears, or limbs? “You could take a chunk of tissue and do all the physics, but it wouldn’t get at what it’s all for,” Fairhall says. “Biology is matter that has meaning. Simulating the tissue is doable, but meaningless.”
The HBP, then, is in a very odd position, criticized for being simultaneously too grandiose and too narrow. None of the skeptics I spoke with was dismissing the idea of simulating parts of the brain, but all of them felt that such efforts should be driven by actual research questions. For example, Xiao-Jing Wang from New York University has built models that show how neurons, if connected in a certain way, can hold on to electrical activity even if they’re not being stimulated—the essence of what we call working memory, or the ability to hold on to thoughts. Meanwhile, Chris Eliasmith from the University of Waterloo has built a model called Spaun, which uses a simplified set of 2.5 million virtual neurons to do simple arithmetic and solve basic reasoning problems.
Countless such projects could have been funded with the money channeled into the HBP, which explains much of the furor around the project. In 2014, almost 800 neuroscientists wrote an open letter to the European Commission saying that “the HBP is not a well conceived or implemented project and that it is ill suited to be the centerpiece of European neuroscience.” A year later, a mediation committee agreed with the critics, asking the HBP to refocus its efforts “on a smaller number of properly prioritized activities” and to retool its unorthodox governance structure.
The HBP acquiesced. It effectively rebranded itself as a software project that curates existing data about the brain, provides tools for searching those data, and develops simulators that will allow others to build their own models. And with the big bolus of funding set to expire in 2023, the team’s recent paper reads like a plea for more investment. “The development of high-quality brain simulators requires a long-term commitment of resources,” they wrote.
In a statement, Katrin Amunts, the scientific director of the Human Brain Project says that, from the outset, the project drew from “a range of different neuroscience fields” to create a computational research infrastructure. “This research infrastructure for neuroscience in Europe—an idea which was proposed at the outset of the project—remains our answer to the challenge of how to decode the human brain,” she says, adding that the project is “creating something available nowhere else in the world, a single, integrated, platform for large-scale collaborative neuroscience.” That new infrastructure will be launched in the fall, under the name EBRAINS.