The first time Kit Parker's phone rang, everything seemed fine. It was January 2006, and Parker's old Army buddy Chris Moroski was calling to say hi.
Parker and Moroski had jumped out of airplanes together in the 1990s when they were paratroopers in the National Guard. But after the attacks on Sept. 11, Parker had been deployed to Afghanistan, his friend to Iraq. They'd lost touch.
"Somehow I realized he's asking for help," Parker says. "It's not being verbalized, but that's why he's calling." Click here to find out how this scientist discovered how a blast effects the brain...click