Why It’s So Hard to Build a Human Brain

Now there’s a tough question to ask. Biologists, neuroscientists, and computer scientists will all give you slightly different answers, but in the end, one theme unites them: the brain is really, really, really complex.

Biology has made progress in brain-building — in late 2020, scientists at Cambridge announced they had grown artificial tissues known as organoids that behaved neurobiologically like brain tissue. This step marks a milestone for understanding how the brain develops over the course of a lifespan since we can now learn from “test-tube brains”.

Computer scientists tell a different story, one of AI and the push to recapitulate human intelligence in computer programs. Efforts here have been fruitful, but progress is slowing. To truly build a human brain needs a little bit of something we don’t have yet — new knowledge about the brain, its parts, and the mysterious ways it works.

The old days of neuroscience: what have we learned so far

Psychologists, neurobiologists, physicians, and neuroscientists alike were once most interested in understanding the brain as a human organ. How does a lump of pink flesh autonomously control most of our daily functions, while also serving as a center for conscious thought, communication, and memory storage? There was (and still is) so much we didn’t know…