Are mice with human brain cells still just mice?

This is a tricky question. The scientists behind the work believe that these mice are not truly human. Throughout the study, the team examined the mice to see if those with human cells were smarter or experienced more pain than mice that didn’t receive the organoid transplant. They found no signs of any human traits or behavior.

But the whole point of implanting human cells is to gain insight into what’s going on in the human brain. So there is a trade-off here. Essentially, animals need to represent what happens to humans without becoming too human. If mice don’t exhibit any human behavior, can they really tell us so much about human disease?

“The question is: What percentage of animal cells are needed in the brain to reduce animal behavior and see different types of behavior?” asked Jeantine Lunshof, a philosopher and ethicist at Harvard’s Wyss Institute for Bionic Engineering.

This raises another question. What do we need to accept that animals are no longer typical members of their own species? Much of the discussion on this topic has focused on moral standing. Most people would agree that humans have a higher moral standing than other animals—whether for research or otherwise, it is unacceptable to treat people the way we treat animals.

It’s hard to pinpoint exactly what makes us different, But the consensus is that it has to do with our brains, which are larger and more complex than those of other animals. It is our brains that allow us to think, feel, dream, rationalize, form social bonds, plan our future, and experience consciousness and self-awareness more generally. Could rodents with human brain cells have the same experience?

This is an important question for bioethicists like Julian Koplin of Monash University in Victoria, Australia. “If we’re talking about humanizing the brains of non-human animals … by bringing in human brain organoids and getting them into animal brains,” he said, “I think we really need to start thinking about whether this can be useful for research animals. any subsequent impact on the moral status of the

In the current study, the answer appears to be no. But that doesn’t mean we won’t see “humanized” or “enhanced” mice in the future, according to Coplin and other bioethicists who specialize in the field.

We need to be careful.

In the study, scientists placed human brain organoids into an area of ​​the brains of mice to help them perceive their environment. But there’s no reason they couldn’t put the same organoids into areas that play a role in cognition or consciousness — which might make cognitive enhancement more likely.

Then there’s the question of how much of the mouse brain is made up of human cells. Transplanting larger organoids could mean that rats are technically “more human” at the cellular level — but that’s not important. What matters, if any, is how its mental state changes.

The mental changes aren’t just about how “humanized” the mice’s mental state has become, either. “You could have an animal that thinks very differently from us, but is extremely vulnerable, or is very intelligent in a way that we humans are not familiar with,” Coplin said.

So far, we’ve been focusing on agile. But what would happen if organoids were put into baby monkeys? Nonhuman primate brains look and work similarly to ours, so they would be better models for studying human disease. But Julian Savulescu, a bioethicist at the National University of Singapore, said: “It does raise the possibility that you will create a humanized primate.”

Savulescu also focuses on cloning. The cells that make up the organoid contain a person’s DNA. What would happen if a large chunk of a monkey’s brain was made up of cells with an individual’s genetic code?

“If you introduce an advanced organoid into a developing primate, you’re likely to essentially create a clone of an existing human,” he said. “It’s not just going to be humanized — it’s going to be a clone of someone who already exists.” That would be the bottom of the moral slide, Savulescu said.

There are many questions here, but few clear answers. No one really knows how to measure moral standing, or when an animal with human cells becomes special—or even a new animal.

But it provides a lot of food for thought.To learn more, check out the following articles technical review file:

In this 2016 article, Antonio Regalado describes researchers’ attempts to grow human organs from pigs and sheep. The purpose here is to create new organs for people who need transplants.

A Spanish stem cell biologist told reporters that the Pope had already blessed such research. But the Vatican later disputed that claim, saying it was “completely unfounded.”

Years later, the same biologist went on to create embryos that were part human and part monkey, As El País reported. Antonio explains why the study is so controversial.

In this recent article, Hannah Thomasy discusses Eight technologies that help us understand the mysteries of the human brain and how we form memories.

You can read more about how our brains shape our thoughts In this article by Lisa Feldman Barrett, which appeared in last year’s Mind issue.

from the web

Can algorithms help those who choose to end their lives? The founders of this nonprofit think so. (MIT Technology Review)

Monkeypox cases have been declining for months. But there are several ways to start here. (nature)

In the US, Covid boosters have been approved for children as young as 5 years old. (Reuters)

Long-term covid is a persistent problem. Months later, almost half of those infected with the new coronavirus have still not fully recovered. (New York Times)

Watch this ping pong game. Then realized it was played by the brain cells in the plate. (Neurons)

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