Why is looking at blue-footed boobies on a rocky boat easier than carrying a cup of tea?

As I carried my cup of tea from the kitchen to the living room this morning, I once again thought about the wonders of the vestibular system, wonders which I feared may have been lost in the length and detail of my previous post. So here goes, a quick and bottom-line account.

If I could keep my hand as steady as I can keep my gaze I could run with that cup of tea and not spill a drop. There is only one part of the body that gets the royal treatment. Lots of brain power is devoted to fixing (in the sense of keeping steady) gaze in space. We care very much about our hands and mouth but we can’t keep them steady. The one steady point that we have is gaze. Pretty cool, don’t you think?

A steady gaze is such a given in everyday life that we will always notice and be extremely bothered when something goes wrong with our vestibuloocular reflex or VOR (a brainstem reflex that moves our eyes to oppose head movements; see last post). Without an operational VOR, the world does not stay steady, we become nauseated and as you may imagine, unhappy enough to seek medical help.

And to return to the topic of blue-footed boobies, here is a picture of a particularly fetching one:

BlueFootedBooby

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