 Your brain gets a signal that says, whoa, I'm running out of oxygen. So your brain puts a shot of adrenaline into your system in order to make you breathe. And that then interrupts the cycle and you take a big gulp of air and breathe. But you've never had your airway hole plugged up. It's simply you've chosen your brain has quit sending a signal to make you breathe. That's neurologic. Neurologic is much more rare. Happens...