The Progressive Era. During the period known as the Progressive Era (1890s to about 1920) the U.S. government became increasingly activist in both domestic and foreign policy.
One possible link between brain freeze and other headaches is local changes in brain blood flow. If further research confirms all these types of headaches are caused by blood flow changes, new drugs that block widening of the blood vessels - called vasodilation - could improve treatment for sufferers.
Because of this, the researchers thought the two might share some kind of common mechanism or cause, so they decided to use brain freeze to study migraines. Headaches like migraines are difficult to study, because they are unpredictable. Researchers aren't able to monitor a whole one from start to finish in the lab.