Currently, the first-choice treatment for PTSD is exposure-based psychotherapy, where therapists help rewire the emotions associated with the traumatic memory in the patient's brain, shifting from fear and arousal to a more neutral response. However, up to 50% of patients fail to respond well to this treatment. In a new study scientists showed for the first time that reactivating therapeutically-altered memories during sleep leads to more brain activity related to memory processing, which is associated with a reduction in PTSD symptoms.