Dr. Justin Feinstein

She knows that she obviously has this brain injury.

Before this study, she didn't really fully understand how deep her lack of fear went.

For years, actually decades, all of the things we had done to probe SM's fear had been external threats.

Sounds, sight.

I'm talking about the brain's ability to sense the inside of your body, the viscera of the body.

So like the heart, the gut, your whole respiratory system, for example.

From the moment we wake up until the moment we go to sleep, and even while we're sleeping, we're just breathing, right?

We take it for granted.

Just breathe normally.

And then I want you to exhale all the air out of your lungs.

Every last drop, nice and slowly, go ahead.

Take as big of an inhale as you can through the mouth all the way till you have no room left.

And hold it and then let go.

And that's it.

That's all it is, is you do that.

Oh, yes, definitely.

I started noticing that I'm hyperventilating and it was automatic.

I'm just going...

and like all of a sudden the periphery of the world feels is like getting a little darker.

And then in my mind, the only thing I could think about at the time was if this continues, I'm going to suffocate.