The incidence of traumatic brain injuries (TBI) has been making headlines due to an alarming increase of cases being reported among athletes and military personnel. This episode focuses on brain injuries affecting military personnel in war zones. Dr. Matt Friedman of the National Center for PTSD (Post Traumatic Stress Disorder) and Dr. Tom McAllister of Dartmouth Hitchcock Hospital in New Hampshire are exploring the association between PTSD and TBI. Dr. Jom Hammack at the University of Vermont is exploring PTSD on a microscopic level.