Dr. Ling is a leading authority on traumatic brain injury (TBI). For many years, he was the leading TBI subject matter expert for the Department of Defense. Dr. Ling is a retired U.S. Army colonel and was deployed as a neurointensive care physician to Afghanistan in 2003 and, to Baghdad, Iraq in 2005. He is presently a professor of neurology at the Uniformed Services University of the Health Sciences and is an attending physician in Neuro Critical Care Unit at Johns Hopkins Hospital. And he was the founding Director of the Biological Technologies Office at the Defense Advanced Research Projects Agency (DARPA) where he served for almost 12 years.