Figure 1.
Mean and standard error for P2 amplitudes measured at Cz, plotted as function of tone intensity for combat-exposed twin with posttraumatic stress disorder (PTSD) (ExP+), combat-exposed twin without PTSD (ExP−), combat-unexposed cotwin of twin with PTSD (UxP+), and combat-unexposed cotwin of twin without PTSD (UxP−).