Fig. 1.

Effect of extinction training on the fear-potentiated startle. A, Timeline of behavioral procedures for experiments B. B, Percentage of startle potentiation before (pre-test), during, and after three sessions of extinction training, context exposure, or light–shock (post-test). The degree of potentiation was significantly reduced only in the light-alone group. It is noted that unpaired controls did not exhibit a decrease in startle responses. *p < 0.05, **p < 0.01, and ***p < 0.001 versus pretests.