What Causes Brain Freeze?

Brain freeze, also known as cold-stimulus headache or sphenopalatine ganglioneuralgia, is a phenomenon triggered by the rapid cooling of the roof of the mouth or the back of the throat. Ice cream and frozen drinks are common culprits.

Upon exposure to cold, blood vessels in the palate suddenly constrict, a response that is detected by surrounding nerves. In particular, when irritated by vessel constriction, branches of the trigeminal nerve, the major cranial nerve that provides sensation to the palate, transmits sensory information to the brain. Normally, this information is relayed to the brainstem, the thalamus, and finally the somatosensory cortex in the parietal lobe of the cerebral cortex. The same pathway originating with the trigeminal nerve, however, also serves the forehead. During brain freeze, the brain misinterprets the source of the pain signal, and unable to distinguish its origins, it defaults to interpreting the signal as coming from skin areas of the forehead. As a result, a sharp headache develops at the front of the head. This misinterpretation of pain signals is known as referred pain. The discomfort usually lasts only a few seconds to a few minutes and typically resolves as the tissues warm up.

Individuals with migraine are more susceptible to brain freeze, probably owing to hypersentivity of the trigeminal nerve and its associated pain pathways. Hence, rapid temperature changes and accompanying constriction and dilation of blood vessels in the palate potentially generate stronger pain signals relative to signals produced in individuals without migraine.