Dr. Jennifer Groh

And then inside the cochlea, there are cells called outer hair cells that can actually expand and contract just the way a little muscle could.

You have one on each side.

It's snail-shaped and it's connected.

The vestibular, your balance structures are also connected to this as well.

And to just describe the flow of information, you've got your outer ear, you've got your ear canal, you have your eardrum, you've got these little bones that connect the eardrum to the cochlea.

And so there's muscles that affect the motion of those little bones, and then there's cells inside the cochlea that can also act like muscles.

these structures get input from the brain.

So we thought, well, if they're getting top-down input from the brain, are they getting a top-down input from the brain that carries information about the position of the eyes?

It seemed kind of like a wild possibility, but not completely out of left field.

Like there was a possible mechanism here that we could imagine.

And the neat thing about this is that we didn't have to do something like stick an electrode into these muscles because they're attached to the bones and attached to the eardrum.

And so if they were being manipulated by a top-down signal from the brain, they would tug these bones and that would tug the eardrum.

And when the eardrum moves, normally it moves in response to sound, but if it moves in the absence of sound, it's going to make a sound.

So you could put a microphone in the ear canal to see whether or not anything was happening in connection with eye movements.

And this, too, wasn't out in left field to do this because there's already kind of known signals generated by these kinds of structures that are measured by clinicians, by audiologists and otolaryngologists.

You can put a microphone in the ear and you can measure things called otoacoustic emissions.

Your ears are making sounds, folks.

It's kind of wild.

Some people make more of them than others.

Exactly.