Dr. Sergiu Pașcă

If you think about it, the human brain builds itself.

Of course, there are instructions, but there's no blueprint.

There's no plan that the brain constantly looks to make sure that it actually made all the connections properly.

Instructions are sort of revealed at every step for kind of like the next step.

And it mostly comes from the cells finding each other.

So I think what we also started to learn from this was that all we need to do is make the parts.

And if we make the parts right, then the parts will come with the instructions and then the circuits will assemble on their own.

And so that has been really kind of like the beginning of it.

And of course, it became progressively more difficult to build circuits.

And so, of course, if you put two, you may think, oh, let's make three.

And if you make three, can you make four?

So actually, we just published a few months ago the first four-part assembloid.

that actually now reconstitutes the pathway that processes sensory information in the nervous system.

So you think about the cortex, you know, sends out to control movement and has an output, but it receives information from the outside constantly.

And that happens through neurons that sit close to the spinal cord

have projections in the skin where they sense tactile vibrations or pain stimuli, send that information to the spinal cord.

From the spinal cord, they cross, they go up to the thalamus in the middle of the brain, and from the thalamus, they go to the cortex.

So this is a four-part pathway.

So it took us years, first of all, to make the parts and then to put them together.

And then, again, the beautiful thing about it is that while we still don't know all the rules of assembly...