Attack of the (Ice Cream) Cones: The Science Behind Brain Freeze

By Kate Huckstep, 2019 Alumni

A nice big scoop of salted caramel gelato… A large refreshing glass of ice-cold water… A 7-eleven “bring your own cup day” bucket of your favourite cola-flavoured Slurpee…

What do all of these things have in common?

Well, at first glance, these may all seem like enjoyable things to experience on a super warm day. But, all of these consumables actually have the power to make your life temporarily less enjoyable. They all have the power to induce the dreaded brain freeze.

A Slurpee-Induced Brain Freeze: Image by Christina Spicuzza via Flickr

About one third of us will know this sensation well: the instantaneous and debilitating forehead pain that appears after rapidly gobbling down something frozen. Most people know it as a “brain freeze”, but the official term is sphenopalatine ganglioneuralgia. “Neuralgia” just means nerve pain, and the “sphenopalatine ganglion” is the collection of nerves located at the base of the brain, near the roof of the mouth.

Why does the cold hurt?

In general, the body does not like rapid temperature changes and has several mechanisms to help it maintain a steady internal temperature. One of these mechanisms has to do with our blood vessels, and specifically, their width.

Constriction and Dilation of your blood vessels, image by Elizabeth2424 via Wikimedia Commons

 

When a part of the body gets really cold, the blood vessels in that area will tend to constrict. This is called vasoconstriction, and it minimises the amount of blood that can flow through that area and be cooled down. You might notice your fingers or toes going pale when you’re out in the cold, and this is exactly why!

On the other hand, when your body gets too warm, blood vessels expand to allow more blood to pass through. When the blood vessels near the skin expand, this allows heat to be released and the body to cool down. This is why people can get flushed or red-faced after being in a warm room or exercising.

So, when a really cold substance hits the roof of your mouth or the back of your throat, it causes a rapid change of temperature there. And it just so happens that at this location we find the juncture of two very important blood vessels: the internal carotid artery (which is responsible for supplying blood to the inside of the brain), and the anterior cerebral artery (which travels along the front of your brain and sits right on top of the brain tissue)

When these arteries are hit with the sudden chill of your rapidly consumed ice cream, they constrict very quickly. The body then compensates for this rapid constriction by sending a bunch of blood there to try warm them back up. This causes them to widen. Scientists think it is this contracting and expanding that triggers pain sensors and creates the sensation of pain.

But why do we feel it at our forehead!?

Our head and face are essentially a mess of several different sensory nerves and blood vessels. While this may be great for creating short lines of communication or the quick processing of our senses, it unfortunately means there is lots of potential for crossed wires and mixed messages. As it turns out, brain freeze seems to be one such case of mixed messages, or what doctors call “referred pain”.

Referred pain occurs when stimuli sensed by one organ is misinterpreted by the brain as coming from somewhere else. A similar thing occurs during a heart attack, when pain from the heart is often felt in the arm.

So, during a brain freeze, pain is sensed by the receptors that sit down near the base of your brain, but it is perceived as coming from the forehead. And that is because of a super important nerve known as the trigeminal nerve.

Trigeminal Nerve Image by BruceBlaus via Wikimedia Commons

 

The trigeminal nerve runs along the roof of your mouth, and it is the nerve that is responsible for delivering the message of pain to the part of your brain that allows you to perceive it. The issue, however, is that this nerve is also responsible for sensory information from your entire face. This is where the message gets a little mixed, and instead we think the pain is coming from our forehead!

The Solution

Brain freeze only ever lasts a matter of moments, but if you can’t bear to just wait it out, there are a few tricks to help the pain subside. You can press your tongue to the roof of your mouth or slowly drink some warm water to try warm the area back up. You can also just try slowing down a touch next time you devour something cold!

 

If you liked this article, Kate also runs a podcast with their brother called Curiosity Killed the Rat. Check them out on Instagram and in Apple Podcasts and Spotify.