Unfortunately for some, the excruciating moment when you guzzle spoonfuls of ice-cream in pure exhilaration only to suffer to agony of a brain-freeze is far too familiar. Brain freeze (or sphenopalatine ganglioneuralgia, if you prefer) occurs when something extremely cold touches the upper-palate (roof of the mouth). Shovelling spoonful’s of Ben and Jerry’s Cookie Dough ice-cream or gulping down mouthfuls of an ice-cold refreshing drink often has us contorting our face, reaching for our temples and gritting our teeth in the torturous few seconds when brain freeze takes over.
Until recently, the cause of brain freeze was unclear and widely debated in the scientific community, but a study by Harvard medical researchers appears to have revealed why it happens. Research conducted by Dr Jorge Serrador, a cardiovascular researcher at Harvard Medical School, revealed that the pain was related to a surge of blood into the brain. The anterior cerebral artery is the main blood vessel to the brain and it sends oxygen to the frontal lobe. Due to the bodies inbuilt homeostatic temperature regulation systems, when the cold sensation is detected, the body pumps more blood to the brain via this vessel. This causes a raised pressure in the skull as the blood surges to the brain, causing brain freeze. In the study, test subjects were given ice water and were asked to indicate when they experienced brain freeze. Scientists noticed a sudden increase in pressure in the anterior cerebral artery as the body’s homeostatic response causes more blood to be pumped to the brain to keep it functioning.
The pain, which is thought to be caused by the increased pressure caused by the blood rushing to the brain tissue, subsides when the blood vessels restrict again to normal.
The brain can’t actually feel pain despite its billions of neurons, but the pain associated with brain freeze is sensed by receptors in the outer covering of the brain called the meninges, where the two arteries meet. When the cold hits, it causes a dilation and contraction of these arteries and that’s the sensation that the brain is interpreting as pain. In the palate, this dilation is sensed by nearby pain receptors, which then send signals back to the brain via the trigeminal nerve, one of the major nerves of the facial area. This nerve also senses facial pain, so as the neural signals are conducted the brain interprets the pain as coming from the forehead—the same “referred pain” phenomenon seen in heart attacks. This is why you often see someone experiencing brain freeze reaching for their temples.
Analysing brain freeze may seem like silly science to some, but “it’s helpful in understanding other types of headaches,” as Wake Forest Baptist Medical Centre neuroscientist Dwayne Godwin, Ph.D. said. With any luck, these new findings point the way toward breakthroughs in understanding how migraines operate, as well as headaches brought on by post-traumatic stress. As Godwin said “we can learn something about headache mechanisms and extend that to our understanding to develop better treatments for patients.” The connection between ice cream headaches and migraines isn’t fully understood, though the link is commonly accepted. A 2001 study conducted by neurologist Peter Mattson of Sweden’s University Hospital found that women who had experienced at least one migraine within the previous year were twice as likely to develop a headache from cold water as those who were migraine-free. Drugs that control the brain’s blood flow could give sufferers of these conditions some much-needed relief. However for the rest of us, gritting your teeth and waiting a few seconds is the only option.
Emma Garside
Image courtesy of Shelly, image hosted on sketchport.com.