You’re eating an ice cream, a seemly delicious and innocent treat, but then Sphenopalatine ganglioneuralgia strikes you down! Also known as brain freeze, this mouthful of a phenomenon is a headache characterised by rapid onset and equally rapid resolution. The reaction is caused by eating something very cold, such as ice cream, too quickly, and it is the body’s warning to slow down. Interestingly, the brain itself cannot feel pain as it has no pain receptors. So the sensation is caused by the receptors in the covering of the brain, known as the meninges. When the cold substance hits the back of your throat, the internal carotid artery (which supplies blood to the brain) and the anterior cerebral artery sense this. The following dilation and contraction of these arteries is interpreted as pain: giving the characteristic brain freeze, ouch!