Dr. Sergiu Pașcă

So it turns out that the brain

the adult brain is not very permissive to forming new connections.

We may form small connections.

There's a lot of plasticity at the connections, but we don't have, let's say in our adult brains, we don't have cells that are moving now across the nervous system.

We don't have entire pathways that are being rewired.

You're never going to have a cortical neuron that just simply regrows and now connects to a spinal cord neurons, which is why injury to the nervous system is so devastating.

There's so little recovery because the cells are usually not, you know, not essentially rejuvenating.

There are no cells that are replenishing them.

It's not just that there are no cells to actually replace them.

It's also that the cells are just not that eager to connect with other cells as they are early in development.

And so years ago, we've discovered that, you know, while we can keep some of these cultures in the dish for very long periods of time and connect them in ever more complex assembloids, and now they're like literally like dozens and hundreds of assembloids that people have made, and not just in the nervous system, actually even outside of the nervous system, because now there are assembloids of cardiac assembloids and endometrial assembloids.

So the concepts are like took over, and I'm glad to talk about it.

We're going to have the first conference on assembloids at Cold Spring Harbor this year.

which is sort of like to bridge across fields and try to understand complex cell-cell interactions.

But even with this most complex assembloids, we realize that the cells are still missing cues that are present in vitro.

So a few years ago, we were doing an experiment looking at some of the neurons that we made in a dish.

And, you know, these neurons in the cortex are very often called pyramidal because they look like a pyramid.

They really have this beautiful triangular shape.

And we were looking at the neuron.

It looked beautiful, exactly like a pyramidal neuron.