Post-retrieval oxytocin facilitates next day extinction of threat memory in humans.

Abstract

Memories can return to a labile state and become amenable to modification by pharmacological and behavioral manipulations after retrieval. This process may reduce the impact of aversive memories and provide a promising therapeutic technique for the treatment of anxiety disorders. A growing body of evidence suggests that the mammalian neuropeptide oxytocin (OT) plays a role in the regulation of emotional memories in animals. However, the effects of OT on threat memory in humans remain largely unknown. This study aimed to investigate the effects of OT administration following threat memory retrieval on subsequent memory expression in human participants. In a double-blind, randomized, placebo-controlled, between-subject design, 61 healthy human individuals completed a 3-day experiment. All the participants underwent threat conditioning on day 1. On day 2, the participants were randomized to receive an intranasal dose of OT (40IU) or placebo after memory retrieval, or an intranasal dose of OT (40IU) without retrieval. On day 3, the participantswere tested for extinction and reinstatement. On day 3, all groups showed equivalent stimulus discrimination during the early phase of extinction. However, the group that received OT following a memory reminder showed a greater decline in stimulus discrimination by the late phase of extinction relative to the two other groups. The results indicate that OT did not block reconsolidation to prevent the return of threat memory but rather interacted with post-retrieval processes to facilitate next day extinction. The study provides novel preliminary evidence for the role of OT in human threat memory.