Vengeance of the Vestibular

I have very bad motion sickness, particularly in cars. That’s why I usually sleep on long rides, or look out the window. When I was younger, I used to read in the car, whether for pleasure or for the stupid NYS Regents exam. But that proved to be a nauseating thing to do, otherwise I would not be applying that experience to neuroscience.

I’m studying the vestibular system, and now I understand the biological mechanism behind my problem.

Normally 3 sensory systems coordinate posture movements: proprioception (stretch in muscles and joints, particularly at the ankles), vestibular (inner ear senses head movement and linear acceleration), and visual (retinal slip where you see the visual world moving in the opposite direction to head movement; try this by moving and looking at your finger from right to left). However, when any of these systems do not agree, sensory conflict results. Let’s use my problem with motion sickness and reading in the car. There is no proprioception at my ankle joint because I’m sitting in the car. My vestibular system senses movement, because the car is taking me down the Long Island Expressway to Flushing. And the problem lies in the absence of visual slip, as I am looking at a stationary book and attempting to make use of a boring drive.

To correct for this discrepancy, we apply sensory-motor adaptation. For instance, I look out the window to make use of my visual system. The car is driving westbound, but I will see slow cars, balding trees, grazing cows, or serene farm fields going eastward. This is typical retinal slip.

I wonder how sleep seems to work as well. Technically, you are also disengaging your visual system. Perhaps snoozing puts you out of consciousness, so your surroundings and motion changes are not affecting the body’s sensory balance as much. Plus, napping is rejuvenating and time flies by much faster. Except, when you have company in the car, you should probably be a good companion and stay awake and look out the window =)

The same case can apply for airplanes, ships, and other forms of transportation (roller coasters too?!). I’ve never been on a cruise or long boat ride, so I cannot speak from experience. And it’s been 8+ years since I was aboard a 14+ hour long trip to Asia, so I cannot relate to that either. I do not have a happy marriage with roller coasters. Last spring break when I went to Orlando, I made a mistake of going on rides consecutively: Revenge of the Mummy twice, the Incredible Hulk twice, the Simpsons 3D ride, Jimmy Neutron, Hollywood Rip Ride Rockit, Men In Black Alien Attack twice, etc… Basically my friends and I Express-ed everything and maximized what we paid for to have a blast in Florida, though I really fudged up my vestibular system those few days.

Yes, you defy gravity by going up at a 90 degree angle... it was SCARY!!!

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