Jad Abumrad

It's all of those different parts of the brain, you know, facial recognition, touch, sound, language, engaged in this crazily complicated, multilayered conversation.

You know, it's one person talking, the other one talking back.

This is Carl Zimmer again, and he says one of the hallmarks of the conscious brain is that you see a kind of conversational logic, a back and forth between the different parts.

Yeah, my turn, your turn, my turn, your turn.

The things you're seeing create signals in the back of your head.

They will go to the front of your head, back again.

forward and back, and forward and back, and forward and back, and forward and back.

And you can use this eavesdropping to calculate how connected the brain is, what they call connectivity.

And when you're awake, you have a lot of connectivity.

When you're dreaming, you also have a lot of connectivity.

And then if someone gives you anesthesia...

Like in a matter of a second, your connectivity just collapses.

Maybe that's what happened to you.

It just cut.

Your connectivity got cut.

It did.

And here is the weird part.

Scientists will like play a sound to somebody who's under with anesthesia.

And they can see that actually the part of the brain that processes sound, the auditory cortex, is active.

It takes in the sound.