Guide Note: At Fort Campbell, Kentucky, thousands of troops are involved in an Army program that records how soldiers' brains work when healthy, providing doctors with comparison data to help diagnose and treat the soldiers if they suffer a traumatic brain injury.

Fast Facts

1. 101st Airborne Division are the new tests 'guinea pigs'
2. Expected to spread to other military bases over the next couple of months
3. Commanders at each base will decide whether to adopt the program