Dr. Jennifer Groh

So we wanted to know if any of these little sounds were being generated with eye movements.

And I wouldn't be here telling you this story if it didn't turn out that, yes, they do.

So we were able to measure that the eardrum is basically moving in connection with every eye movement, every saccadic eye movement.

These are the fast jerky eye movements.

There's other kinds of eye movements and we haven't yet tested them.

The signal is very precisely time locked to the onset of the eye movement.

And the effect is different in the two ears so that if your eyes are moving to the left, the eardrum on the right is going to kind of bulge inward, then outward, then inward.

I might have this backwards.

But whatever the right ear is doing, the left ear is doing the opposite so that the eardrums are going to be moving in the same direction.

One is going to be inward when the other is going outward.

Like a wave, exactly.

Like a wave, not like a... Not like flapping.

Not like flapping, exactly.

You know, we're still actually at pretty early days in understanding this process and what it's for, but it's a very precise signal.

It turns out to carry information about how far the eyes are moving to the left or to the right, as well as a bit less, but some information about vertical movements as well.

And we think that this may be kind of the first step in that integration of visual and auditory information.

Right, or help you stay oriented, like with respect to like knowing what's up and what's down and staying upright.

I think it's all part of an integrated system.

You know, we talked about the top-down control over the ear, but there's a lot of top-down control over vision, too.

And some of it is a little easier to understand than what I just described because blinking is top-down control over vision.