Social support facilitates threat extinction retention in humans: an fMRI study.

Extinction is a recognized process for extinguishing threat memories; however, the process of extinction can be emotionally challenging, and the effect is usually short-lived. Animal studies have shown that peer presentation can inhibit freezing behavior and prevent return of the threat memories, suggesting that social support may enhance threat extinction. However, the role of social support in maintaining human threat extinction remains unclear. The present study examined the effect of social support on threat memory extinction in humans, and its underlying neural substrates. Succeeding threat conditioning on Day 1, participants were randomly assigned to the social support and no-support groups using random numbers and experienced either a social support intervention or no intervention before threat extinction procedure on Day 2, subsequently, they underwent spontaneous recovery and reinstatement tests on Day 3. A total of 96 participants completed the three-day threat extinction retention tests; 59 participants completed Day 3 tests within the fMRI scanner; 77 participants returned to the laboratory two weeks later and participated long-term threat extinction retention tests. Results showed that friend interaction significantly increased individuals' social support perception, which then reduced threat response and prevented the return of threat memories; and the effect was long-lasting. The fMRI results suggested that emotional memory-related brain regions, including the hippocampus, thalamus, and precuneus, were inhibited in the support group. By extracting these differential brain areas between support and no-support groups as regions of interest, connectivity analyses showed a significant difference in the functional connectivity of the thalamo-cortical circuits between the support and no-support group. This research highlights the positive role of social support in human threat extinction retention and related neural activations, which provides a potential strategy for treating threat- and trauma-related disorders.