<P> 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 . Brain - freeze pain may last from a few seconds to a few minutes . Research suggests that the same vascular mechanism and nerve implicated in "brain freeze" cause the aura (sensory disturbance) and pulsatile (throbbing pain) phases of migraines . </P> <P> It is possible to suffer from a cold - stimulus headache in both hot and cold weather, because the effect relies upon the temperature of the food being consumed rather than that of the environment . Other causes that may mimic the sensation of cold - stimulus headache include that produced when high speed drilling is performed through the inner table of the skull in people undergoing such a procedure in an awake or sedated state . </P> <P> Another theory into the cause of cold - stimulus headaches is explained by increased blood flow to the brain through the anterior cerebral artery, which supplies oxygenated blood to most medial portions of the frontal lobes and superior medial parietal lobes . This increase in blood volume and resulting increase in size in this artery is thought to bring on the pain associated with a cold - stimulus headache . </P> <P> When the anterior cerebral artery constricts, reining in the response to this increased blood volume, the pain disappears . The dilation, then quick constriction, of this blood vessel may be a type of self - defense for the brain . </P>

What actually happens when you get brain freeze