Tyler’s technology, packaged in a warfighter’s helmet, would allow soldiers to flip a switch to stimulate different regions of their brains, helping them relieve battle stress when it’s time to get some rest, or to boost alertness during long periods without sleep. Grunts could even relieve pain from injuries or wounds without resorting to pharmaceutical drugs. More importantly, in the periods after brain trauma ultrasound technology could reduce swelling and metabolic damage that is often the root cause of lasting brain damage.