This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Eager eaters know that gulping a Slurpee or inhaling a sundae can cause that brief seizing sensation known in the not-so-technical literature as "brain freeze" or "ice cream headache."
Just what causes this common cautionary condition has remained mysterious to sufferers and scientists alike (not that the two categories need remain mutually exclusive).
A new study, presented April 22 at the Experimental Biology 2012 annual meeting in San Diego, proposes a probable answer. And it's one that could also suggest new treatments for more serious conditions, such as migraines and traumatic brain injuries.
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The findings were not easy to obtain and required 17 courageous volunteers to submit themselves to brain freeze. These healthy, self-sacrificing adults took sips of extra-cold water through a straw, which they aimed at the roof of their mouths. While their lips were sipping away, subjects' brains were monitored via transcranial Doppler, which can sense changes in arterial blood flow. As soon as volunteers achieved and then emerged from a freeze, they alerted the researchers.
Researchers then were able to pinpoint changes in brain activity at those precise moments, comparing those signals with measurements taken under control conditions when subject sipped on room temperature water.
The team, led by Melissa Mary Blatt, of the Department of Veterans Affairs New Hersey Health Care System, found that just before brain freeze, the anterior cerebral artery opened wider and pumped extra blood to the brain. This artery is one of two in charge of bringing blood to the frontal lobes, which is also where subjects reported the greatest freeze pain. This response might be the body's effort to keep the brain from getting too cold by supplying it with a blast of warm blood.
Tellingly, as the vessel contracted back to its normal diameter, the pain went away.
The researchers suggested that the pain might stem from the excess pressure generated by this quick burst of blood into the closed skull cavity.
A similar blood-induced pressure might also be partly responsible for migraines, traumatic brain injury headaches and others, the researchers noted. If that turns out to be the case, new treatments that prevented this quick dilation of the blood vessels could be key in turning down pain for many headache sufferers.
For the rest of us, perhaps we should try to sip, slurp and lick a bit more slowly.