Sci loves Portal. I think it's a magnificently clever game, and Portal 2 is the in the same vein. I love the songs, I love the humor, and I love the concept (puzzle solving with a giant gun! That makes portals!), and I DESPERATELY want to play.
Sci, not unlike many people on this planet, is a sufferer of motion sickness. I've never been able to read in the car, and sitting in the back seat is often too much. Heck, sitting in the FRONT seat is sometimes bad! And Portal. Whooooo, Portal. Just WATCHING Portal makes me green in about 2 minutes, and attempting to play myself...well I only lasted about 30 seconds.
Motion sickness is caused by a mismatch between the perception of movement (say, moving in a car), and what your sense of balance perceives (that you're sitting still). Finally the difference in perception causes dizziness and nausea. It's stronger in some than in others, and for those of us who are really weak of stomach, well, we can thank an overactive vestibular system.
Last week we covered the basics of the auditory system, controlled by cranial nerve VIII, the vestibulocochlear nerve. But the "vestibulo" part of the vestibulocochlear nerve is, though in the same general location, something else entirely. Because cranial nerve VIII not only controls your hearing (the -cochlear part), it also controls your BALANCE and sense of how you're moving through space. While this may seem to most people like it's merely a matter of avoiding sharp objects and not embarrassing yourself on the dance floor, knowing your orientation in space is a universal issue for all living creatures. It's something we don't really think about, but are you facing up or down? Where is your head relative to your feet? When you're moving forward, how do you know how FAST you're going? These are all questions for your vestibular system.
And the vestibular system is OLD. All jawed vertebrates, you and the fish you just ate, and the chicken you had for dinner, pretty much have the same vestibular system setup.
(Click to embiggen)
You can the the cochlea sitting there, like a cute little snail, right where we covered it last time. Now, look just above it and slightly to the left. You see those two arches? Those are part of your semicircular canals. And those loops detect position and acceleration...and determine whether you're feeling motion sick.
If you'll excuse me, I'm feelin' a bit queasy talking about all that acceleration...
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