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.
Closed brain injury. Closed brain injuries occur when there is a nonpenetrating injury to the brain with no break in the skull. A closed brain injury is caused by a rapid forward or backward movement and shaking of the brain inside the bony skull that results in bruising and tearing of brain tissue and blood vessels.