Brain freeze is a sudden headache in your forehead and temples after eating something cold, like ice cream. Known medically as cold-stimulus headache, it happens because extreme temperature change on your palate causes your blood vessels to constrict and reopen rapidly.

Most neuroscientists believe that brain freeze is caused by the way cold stimuli affect blood vessels in the roof of your mouth. When you eat something cold, the blood vessels constrict and then quickly expand. This expansion causes a rapid influx of blood, which can lead to pain in the head and temples.

Brain freeze. Another explanation, according to Caudle, is that we get brain freeze when the internal carotid artery — the artery at the back of the throat that sends blood to the brain — experiences a sudden temperature change when we drink or eat something cold. Caudle also explains that, despite the name, “your brain isn’t actually feeling pain.