The innermost part of the brain is complete, with a visual cortex and autonomic breathing mechanism appropriate for a tadpole type creature, but larger. It is not hooked into the conscious mind, but otherwise blind people can frequently “see” with the visual cortex. (They know something is there and avoid hitting it, without being able to describe it, for example.) If the breathing section of this brain gets activated, it breaths in a hiccup. There is no cure. You have to somehow override it. We’ve all done it at one time or another.
I swear by this trick. I used to get them all the time. My mom would take an electric cord with its end cut of and stripped back ,She would plug it in and then draw it across my sternum quickly. worked every time