2. Research Design: The longitudinal research design for this project will be a three factor mixed factorial design with between subject factors of PTSD (+PTSD x -PTSD) and cognitive remediation [cogrem x video game] and within subject variable of time tested (pre-training, post-training, 3 month follow up). There will be 40 participants enrolled in the following groups of 10 each: 1) +PTSD/cogrem, 2) +PTSD/video game, 3) -PTSD/cogrem, and 4) -PTSD/video game. PTSD status is determined by a diagnosis of PTSD identified through a clinical interview for DSM-IV diagnostic criteria for PTSD. The active treatment is cognitive training. Veterans in this group will receive the Posit Science (Mahncke et al., 2006) visual cognitive remediation paradigm of 40 hours of training. The control treatment is a video game designed by Nintendo for the DS handheld system, which intended to improve mental functioning called Brain Age (Nintendo, Inc.) which will be played for 40 hours. Groups will be compared on the difference scores for neuropsychological, neurobehavioral and neuroimaging data to see if there is a benefit in cognitive training and if that benefit is greater in the group with PTSD.