--- title: "Scientists Transplant Human Brain Cells Into Living Rat Brains" description: "In a major neurological breakthrough, Stanford University scientists have successfully transplanted human brain cells into the brains of live rats." date: "2022-10-13" modified: "2022-10-13" authors: - name: "Maggie Harrison Dupré" job_title: "Senior Staff Writer" link: "https://futurism.com/authors/mharrison" url: "https://futurism.com/neoscope/scientists-transplant-human-brain-cells-rat-brains" categories: - "Brain" - "Health & Medicine" - "Neuroscience and Brain" tags: - "brain" - "brain science" - "neurological disorder" - "neurons" --- # Scientists Transplant Human Brain Cells Into Living Rat Brains ![In a major neurological breakthrough, Stanford University scientists have successfully transplanted human brain cells into the brains of live rats.]() *\Image: Getty Images/Futurism\* In a breakthrough study providing evidence that it's indeed possible for neurons of one species to form and function within the brain of another, Stanford University scientists have successfully transplanted human brain cells into the brains of live rats. And they're DEFINITELY not making human-rat monsters and/or mutant rodents designed to train similarly mutated teenage turtles, okay? That being said: if neither of those are the use cases for this eerie breakthrough, what is? As [*The Daily Beast* explains](), scientists often rely on organoids — in short, self-assembling groups of stem cells that form three-dimensional models of complex organ cells or tissue — to study and experiment on human brain cells. While useful, they have their drawbacks. At their best, organoids are only mimics, and tend to do so imperfectly. When it comes brain organoids in particular, neurons struggle to grow to their typical size and form strong bonds with one another, as real brain cells do inside of our heads. Basically, though brain organoids may offer *some* scientific insight, it's not much. And that, friends, is where the rats come in. The study, [published in the journal *Nature*]() and led by Stanford professor of psychiatry and behavioral science Sergiu Pasca, has a fairly simple — if slightly gruesome-sounding — hypothesis: if we can successfully transplant human neurons into the brain of a rat, we can, in a way, make a better, more realistic version of an organoid. In other words, they wanted to turn a rat's brain into a poke-able, prod-able, human-adjacent site to study live-action human neurological function — and with it, neurological disorders. "Psychiatric disorders are a huge burden to society," Pasca said during a press briefing, according to the *Beast*. "I believe we have a moral imperative to find better models to study these conditions." To test the theory, the scientists transplanted brain cell organoids — obtained from human donors — into the brains of over 80 newborn rat babies. The rattos were then pretty much left alone for eight months to grow into adults, fed and raised normally by the researchers. Per the study, those xenoplanted neurons grew to take up one-third of a hemisphere in the rats' brains, growing up to six times larger and forming bonds much stronger than those grown in petri dishes. The affected rats were also able to tell red light from blue light, which normal rats can't — a sign that the human-borne neurons had integrated with the rats' "neural circuitry," as Pasca told the *Daily Beast*. Eep! That being said, the rats' brains were still mostly rat, and the stem cells didn't always grow as they would within a human brain. Still, the research provides strong evidence that when rat brains are effectively used as a new-and-improved petri dish, they offer a far more advanced means to study human brain function than any in-petri organoid ever could — especially considering that when the scientists implanted a different group of rats with organoids derived from human folks with Timothy syndrome, they were able to see that the disordered neurons grew and spread differently than normal ones. Of course, while this is a fascinating and potentially fruitful breakthrough, it obviously raises some serious ethical questions. It's fairly disturbing to think about intentionally giving a rodent a brain disorder, and on a deeper level: how ethical is it at all to fuse the minds of two species, and are we effectively then experimenting on the minds of tiny — if hybrid — humans? "We're going to have to think very carefully together," Pasca told the *Daily Beast*, "what are the models and how far we want to go." **READ MORE:** *[Mindbending Experiment Fused Rat Brains With Human Neurons]()* \[*The Daily Beast*\] **More on rat brains:** *[Scientists Fed Rats Sugary Soda for Two Months and They Got Demonstrably Stupider]()* ## Author At Futurism, I've reported extensively on the rise of AI as a cultural and business force shaping the media industry, and more broadly how those dynamics are changing how we all consume and share information and relate to one another. I'm also fascinated by public health policy and ethics, the role of emerging tech in politics and governance — and the powerful people and forces at those intersections — climate change, and the environment. My investigation on Sports Illustrated's use of AI-generated authors with fictional biographies won a 2024 Mirror Award for "Best Story on Media Coverage of Artificial Intelligence in Journalism and the Media" from Syracuse University's SI Newhouse School, I contributed to Niemen Lab's 2025 Predictions for Journalism series, and I've discussed my work for Futurism during appearances on NPR, CNN, the BBC, the CBC, and more. I grew up in rural Pennsylvania and attended the University of Massachusetts Amherst, where I played Division I field hockey for the Minutewomen as a midfielder. Since then, I've lived in New Orleans, Louisiana and Manhattan, New York. I spend my free time running, reading, perusing archival fashion, and searching for the world’s best negroni. I also have a debonair tuxedo cat, Westley, who's named after "The Princess Bride." ### Author social links [Bluesky]()