There is nothing quite like an ice cream cone or slushy on a hot summer day until — brain freeze — aargh. Why does something so enjoyable come at the risk of such pain?
First, what most of us call brain freeze has another name that is a mouthful: sphenopalatine ganglion neuralgia. In the roof of your mouth, the palate, there are many little blood vessels called capillaries and a bunch of nerve fibers called nociceptors, which can detect painful or noxious stimuli. The name nociceptors is from the Latin word, noceo, which means “hurt.” The free ends of nociceptors in the skin, muscle, joints, bone and internal organs convert pain stimuli into electrical signals called action potentials that are transmitted up from the nerves to the spinal cord or brain.
There are several different kinds of nociceptors, categorized depending on their responses to stimulation due to damage, inflammation or tumors. There are four kinds of skin nociceptors, each responding to a different stimulus: heat, mechanical stimulation like a pinch, chemical substances and high intensity signals of all kinds.
The capsules and ligaments of joints have high-threshold receptors to mechanical stimuli, receptors to high-intensity stimuli and “silent” receptors. Internal organs contain nociceptors for mechanical pressure, temperature and chemical stimuli, and silent nociceptors that are scattered about. The silent nociceptors are normally unresponsive but can be activated with inflammation or after tissue injury.
Evolution has ensured that we cannot ignore pain — we need to get ourselves out of the situation that caused the pain. There are three cooperative pain signaling pathways to help ensure we are aware of the pain. There are people who cannot feel pain due to an inherited disorder called congenital insensitivity to pain or CIP. People with CIP are easily injured and often die prematurely. Many people with CIP also have anosmia, a complete loss of the sense of smell.
So back to the brain freeze. That big bite of ice cream causes the capillaries in the roof of your mouth to constrict, and it happens so quickly that the nociceptors send a signal of pain up your trigeminal nerve to your brain. In a study in 2012, 13 volunteers were asked to drink ice water through a straw to ensure the water hit the palate. The study showed that in addition to the capillary constriction, there is also a dramatic and sudden increase in blood flow in an artery in the brain, which increases pressure in the brain and causes pain. This may be a response to ensure the brain remains warm. Brain freeze pain is severe enough that people stop eating ice cream and in a few minutes, the pain disappears, which coincides with a constriction of the artery in the brain.
So what can you do to treat brain freeze? Drink some warm liquid or push your tongue against the roof of your mouth to help warm the palate and dissipate the pain more quickly so that you can enjoy the rest of your ice cream. We wouldn’t tell you not to eat ice cream!