Social buffering during fear extinction rescues long-term trauma-induced memory and emotional behavioral alterations in rats

Post-Traumatic Stress Disorder (PTSD) is a psychiatric disease that may develop after experiencing a traumatic event and it is characterized by resistance to extinction of the traumatic memory. Psychotherapy, which mainly focuses on favoring fear memory extinction, represents the first-line treatment for PTSD. However, this approach is not always successful. Emerging evidence suggests the importance of a social support in alleviating PTSD symptomatology; however, the efficacy of group therapy for PTSD remains controversial. Here, we evaluated the impact of social support on the efficacy of fear extinction sessions in a chronic PTSD-like rat model. We tested the hypothesis that the presence of a social partner during temporally spaced extinction sessions (to mimic the presence of a social support during therapy) or after the extinction sessions in a neutral environment (to mimic the presence of a social support outside of the therapy setting) would ameliorate long-term PTSD-like symptomatology. Extinction sessions were carried out under different conditions: (i) alone; (ii) with a social partner never exposed to the trauma; (iii) with a trauma-exposed partner. In a separate set of experiments, rats were exposed to the extinction sessions alone and, immediately thereafter, paired with a social partner, as indicated above, in a different context. Extinction sessions carried out in the presence of a social partner never exposed to the traumatic experience rescued long-term trauma-induced PTSD-like symptomatology. We provide evidence of beneficial effects of a "healthy" social support during extinction sessions in ameliorating both immediate and persistent over time cognitive and emotional PTSD-like symptoms.