system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is really happening when I get a brain freeze?
gpt
When something cold touches the roof of your mouth, it causes a quick temperature change to the surrounding tissues. To compensate for this, blood vessels to the roof of your mouth dilate to allow more blood to go to the area to warm it back up. A side effect of this dilation releases 'pain signalers' that tell your brain there is something painful going on, which is essentially the quick temperature change.. This is usually perceived in your face or forehead because nerves in this area are all connected.