The sense of smell is the oldest and perhaps most evocative method to trigger memory and emotion: Imagine the scent of a newborn child. A whiff of fir trees from a forest trail. The acrid smells of a war zone, such as diesel fuel and burning rubber. Scent is the only sense that is directly linked to the memory and emotion section of the brain making it a powerful tool for affecting cognition and behavior. Combining this primal sense with rapidly evolving virtual reality (VR) technology — enabling medical applications including helping soldiers with post-traumatic stress disorder (PTSD)— is the mission of OVR Technology, a startup in Burlington, Vt.