To Better Understand Diseases, Researchers Generate Human Brain Cells In Rats.

Human brain cells were grafted into the developing rat brains, where the cells developed and connected.

Understand Human Brain Better

It’s a part of an effort to learn more about the disorders that impact the most complex organ in the human body, the brain, which makes us who we are but has long been shrouded in mystery.

Although “the human brain has not been very accessible,” Dr. Sergiu Pasca, senior author of research explaining the discovery, noted that “many illnesses like autism and schizophrenia are likely uniquely human.”

“Promising avenues in tackling these diseases” are methods that don’t entail removing brain tissue.

The study relies on the group’s earlier efforts to create “organoids” that resemble the brain and other human organs like the liver, kidneys, and prostate or essential portions of them.

Scientists at Stanford University converted human skin cells into stem cells and then persuaded them to differentiate into several types of brain cells to create brain organoids. These cells subsequently multiplied to create organoids that resembled the cerebral cortex, the outermost layer of the human brain and a crucial component of memory, thought, learning, reasoning, and emotions.

These organoids were inserted into 2- to 3-day-old rat pups when the brain was still developing its neural connections. The organoids developed to the point where they eventually took up a third of the rat’s implanted hemisphere of the brain. Organoid-derived neurons established functional connections with neural circuits in the brain.

Rodents have previously received human neurons through transplantation, mainly in adult mice. This is the first time these organoids have been implanted into young rat brains, according to Pasca, a professor of psychiatry at the Stanford School of Medicine. This process produced “the most advanced human brain circuitry ever built from human skin cells and a demonstration that implanted human neurons can influence an animal’s behavior.”

The Timothy syndrome, a rare genetic condition linked to heart issues and autism spectrum disorder, was studied by scientists who implanted organoids into both sides of a rat’s brain. One of the organoids was made from the cells of a healthy person, and the other from the cells of a person with Timothy syndrome.

They first noticed disease-associated effects related to the activity of the neurons five to six months later. Electrical activity on the two sides was different, and the neurons from the Timothy syndrome patient were significantly smaller. They didn’t sprout as many extensions that could pick up input from neighboring neurons.

According to Dr. Flora Vaccarino of Yale University, the discovery advances the discipline, which previously created lumps of the cerebral cortex using DNA from autistic patients.

Vaccarino, who wasn’t involved in the study, said, “It’s imposing what they do here in terms of what these cells can truly show us in terms of their advanced development… in the rat.”

Such animal testing raises ethical questions. For instance, Pasca claimed that he and his colleagues are aware of the rats’ welfare and if they continue to behave normally in the presence of the organoids, which he claims they do. Pasca disagrees that this should be tested on primates, though. Researchers currently say it is implausible for brain organoids to develop something akin to human consciousness, but ethical theorists are interested in the potential.

Outside of animal studies, several scientists are investigating human brain organoids. For instance, researchers from ETH Zurich in Switzerland described how they are developing brain-like tissue from stem cells in the lab and mapping the cell types in distinct brain regions and genes governing their growth in a report published in Nature earlier this month. Some are using these structures to research autism.

According to Pasca, brain organoids could be used to evaluate brand-new therapies for neuropsychiatric illnesses, which are the leading cause of disability worldwide. He claimed that the difficulty of accessing the human brain has prevented scientists from making significant advancements to this point, which is “the reason why we’re so much more behind in psychiatry compared to any other discipline of medicine in terms of treatments.”

Research Funding

Researchers said they could conduct the same kinds of experiments using organoids made from the cells of people with disorders like autism or schizophrenia — and possibly learn about how these conditions affect the brain. The National Institutes of Health partially funded their study.


Gloria Flynt

I am a Research Content Specialist in I have been working with for over 6 months. is a digital platform that provides news and analysis on business, economy, technology and entrepreneurship in worldwide. I love reading and writing about anything that has to do with science, technology, and developments in the digital world.

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