As the United States draws troops from Afghanistan and Iraq, a source of injury and death will cease. But research by the Veterans Health Administration will continue. Two years ago we checked in with one of VA's top researchers into brain injury and neuropathology. The chief of neuropathology at the VA Boston Healthcare System, Dr. Ann McKee returned to Federal Drive with Tom Temin for an update.\nLearn more about your ad choices. Visit podcastchoices.com/adchoices