Although yawning seems like a small, everyday action, recent studies have found that it causes an unexpected reaction in the fluid protecting the brain. A research team in Australia reports that a yawn pressurizes the cerebrospinal fluid away from the brain, and causes a reaction that is quite different than simply taking a deep breath into the lungs. This research at the University of New South Wales, conducted with advanced MRI scanning technology, looked at how the brain migrates and moves during a yawn, as well as the amount of time it takes to migrate the CSF during the yawn. Adam Martinac, a neuroscientist at UNSW, and the researchers studied 22 healthy people and discovered some patterns that could explain the evolutionary pathway of yawning in many mammal species, including people. Although there are still questions regarding why people yawn, scientists have discovered that yawning occurs in nearly all mammals, and most mammal species are capable of spreading the behaviour to one another. The UNSW team systematically studied the physiology of yawning, normal breathing, a …