What causes motion sickness? - Big Questions - (Ep. 210) | Mental Floss

Hi, I'm Craig. I'm always moving and this is Mental Floss Video

Today I'm going to answer Craig's big question, what causes motion sickness

I don't remember asking that. Man, I've stopped moving. Motion sickness is when someone experiences symptoms like nausea or dizziness when their perception of movement differs from their vestibular system's feeling of movement

Today I'm going to talk about why that is. Let's get vestibular. There are three different types of motion sickness

The first one involves things like air sickness, sea sickness, and possibly car sickness, which

occur when a person's vestibular system senses motion, but the motion isn't seen

The vestibular system, by the way, is what senses balance, motion, and equilibrium

It can be found in the inner ear. And so can wax. The second type of motion sickness is when the visual system detects motion, but the vestibular

system doesn't. This is like when an IMAX film makes you feel dizzy. And the final type

of motion sickness occurs when both the visual and vestibular sense motion, but they don't

feel related. Experts, as usual, don't know for sure what causes motion sickness in these

situations, but there are a few prevailing theories. The most common one is simply that

the conflict between visual and vestibular systems causes dizziness. There's also the

nystagmus hypothesis my nickname in high school which states that motion sickness is caused by the vagus nerve one of the cranial nerves that brings signals to the brain This nerve takes note when the eye muscles have the reflexive traction that accompanies the detection of motion so the vagus nerve triggers the feeling of nausea

Or nausea. Another theory is that motion sickness is more psychological. The vestibular system that I mentioned earlier tells the brain that it detects motion, but

the eyes don't recognize that same motion, so the brain believes that it has encountered something that's poisonous to the brain

And this leads to nausea, or vomiting, an attempt to get rid of the poison. In the 70s, psychologist Dr. Michel Treisman claimed that this is an evolutionary response to food poisoning

There are also new theories being developed, like at the University of Minnesota, kinesiologist Dr. Stofragen has been studying motion sickness for years

He believes that it's not connected to the inner ear at all. Instead, he thinks it's the body attempting to maintain posture, then getting dizzy when it's unable to

The Naval Aerospace Medical Institute has also been studying motion sickness, so they can develop medication to treat it

They've found that it's related to neurotransmitters like these ones. Interestingly, medications that treat nausea caused by things like food poisoning and chemotherapy

don't tend to effectively treat motion sickness. So that suggests it's a unique type of nausea

Or nausea