We conducted a first-of-its-kind study comparing the brains of people with and without PTSD when they recall traumatic memories. This is the first study to look at connections across the entire brain while people recall traumatic memories, rather than focusing on isolated brain regions. Our study also helped explain why people with the Dissociative Subtype of PTSD often feel disconnected when recalling traumatic memories or facing reminders of their trauma. When recalling traumatic memories, the PTSD-impacted brain may rely more on basic survival responses (e.g., fight, flight, freeze). This could help explain why traumatic memories in PTSD often feel so real and overwhelming – these memories feel as if they are happening right now, in the present.