Nausea and vestibular dysfunction

[Joseph J. Strout]

On 6 Apr 1995, WB Thomas wrote:

> A student recently asked me a question I can't answer. Why are
> autonomic signs such as nausea and vomiting often associated
> with vestibular disease? I am interested not so much in a
> neuroantomical explaination, but rather any possible evolutionary
> benifit in vestibular input to the emetic center.

Many neurotoxins have the effect of causing visual and vestibular inputs 
to become "out of sync" with each other; in fact I suspect that this may 
be the earliest symptom for at least some toxins.  Toxins can often be 
ingested, and in that case, the most adaptive response is to vomit.  
Since we evolved without vehicles, space travel, and roller coasters, it 
was probably a good idea to vomit whenever visual and vestibular inputs 
are desynchronized (thus, motion sickness).  Vestibular disease probably 
causes nausea for the same reason -- you're more likely (says evolution) 
to have eaten something poisonous than to have contracted such a disease.

I apologize for not having any references to back this up -- consider it 
my $0.02 worth.

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|    Joseph J. Strout		Department of Neuroscience, UCSD   |
|    jstrout at ucsd.edu		http://sdcc3.ucsd.edu/~jstrout/    |
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