Cerebral organoid

In biology, competition dictates growth.

By removing the aggressive, fast-growing mouse cortex, researchers provided a blank canvas that allowed human brain organoids to expand massively and integrate deeply into a host's nervous system.

And number two, the environment unlocks hidden genetic potential.

Given enough physical space and the right living physiological incubator, human stem cells can self-organize to produce rare, incredibly complex cells like von Economo neurons.

It is a completely physiologically irrelevant model for human neurology.

We cure Alzheimer's in mice every week in the lab, but those drugs do absolutely nothing in human trials because the underlying disease pathway is different.

Organoids, however, offer a direct identical genetic mirror to human neurology.

And the only other option we currently have that comes close to human neurology are non-human primates, right? Monkeys.

Yes.

Obviously, we have a heartbeat.

Right.

Organoids floating in a lab dish do not have a heart, and they do not have blood flow.

Welcome back to the Nature Podcast.

This week, transplanting human brain organoids into mice-

And how to turn a scientific paper into an AI you can talk to.

I'm Nick Petriw Chow.

So both because of the complexity, the maturation, and the connectivity, I would say that this is not a human brain in a mouse, but rather is a organoid that is being pushed to progress in its development.

Other researchers that Nature has spoken to echo this sentiment, saying that these are not fully formed functional human cortexes.

Aparna says she commends the researchers behind the work for their engagement with ethicists throughout this work, something echoed by Emily Jackson from the London School of Economics, part of whose work focuses on the regulation of stem cell-related research, which includes brain organoids.

So one thing that's really, really striking about this paper, but also about the work of Sergiu Pasca's lab in general and other work that he's done, is how focused this group is on the importance of ethics and the importance of regulation.