Researchers conducted test on 42 Americans soldiers and found that scanning brain might help diagnose post-traumatic stress disorder (PTSD). The male and female soldiers who had comparable levels of combat exposure were divided into two groups, those with PTSD (22) and those who didn't have the condition (20). FMRI was used to observe the brain patterns of the soldiers while they performed a three-part, short-term memory task that included distractions. The task is intended to measure the ability to stay focused, which is reduced in people with PTSD. The researchers noted a number of brain activity differences between the PTSD group and the non-PTSD group, such as in the dorsal lateral prefrontal cortex, an area that plays a role in the ability to stay focused. While doing the memory task, the soldiers with PTSD performed more poorly when they were shown both traumatic and neutral photos, while the soldiers without PTSD were only distracted by the traumatic photos. The researchers also noted marked differences in an area in the medial prefrontal cortex that governs sense of self. This area showed a much higher level of activity when the soldiers with PTSD looked at combat photos, but showed little response in those without PTSD.