Influence of intranasal oxytocin on fear consolidation in healthy humans

Background Although recent data in healthy humans suggestthat treatment with intranasal oxytocin (OT) may facilitate extinction recall,to date, little is known about the effects of OT on memory consolidationprocesses. Aim To examine the effect of intranasal administration of OT compared with placebo on memory consolidation blockade of a de novo fear memory in a classical 2-day fear conditioning procedure. Results There were no significant differences between the OT and the placebo groups on the first two extinction trials (mean (SD)=0.01 (0.39) vs 0.15 (0.31), t=-1.092, p=0.28). Similarly, during early extinction, analysis of variance for repeated measures failed to show significant main effects of extinction trials: trials (F(4, 112)=1.58, p=0.18), drug (F(1, 112)=0.13, p=0.72) or drug × trials interaction (F(4, 112)=0.76, p=0.56). Conclusion Our results suggest that OT administered in a double-blind fashion immediately after fear conditioning does not significantly reduce consolidation of fear learning as measured by a differential skin conductance response tested at the beginning of extinction.