Re: How do your eyes affect balance?

Jenna-

I'm not sure what you've uncovered so far, but I'll try to direct you to some sources that contain some more information on the topic.
As you've probably discovered, we still have a lot to figure out concerning how the brain works, especially when it comes to mixing of sensory modalities, such as vision and balance. Just to make sure the bases are covered, I'll start from the basics.

The two systems we are concerned with are the visual system and the vestibular (balance) system. The input for the visual system, as you know, is the eye. The input for the vestibular system is in your inner ear, consisting of the semicircular canals, and two other small organs called the otolithic organs (technically called the utricle and the saccule). These otolithic organs are the real keepers of balance, as they detect gravity and acceleration of your head.
Both of these systems send messages all over the brain, and undoubtedly they criss-cross at various points. Various reflexes which use both the visual and vestibular system have been studied pretty well, but I'm not sure they address the questions you're interested in. But I'll mention it just in case it does shed some light: it's called the Vestibulo-Ocular Reflex (VOR). It's the way your brain knows how to move your eyes when your head moves.

For some more info, I'd suggest looking at a neuroscience textbook as well as the internet. One of the classic textbooks is Eric Kandel's "Principles of Neural Science", but any text you find at your local library should do. To get more details on these systems, I'd look up information (in the texts and on the internet) about the otolithic organs and where they go in the brain. Also, I think the information of the visual system that would help with balance would go through a part of the brain called the superior colliculus. I would also look up the VOR, just to see if it's of use to you.

I hope that helps - good luck on your project!

Alex Goddard
cgoddard@fas.harvard.edu