Fig. 2. vmPFC-amygdala circuit stimulation facilitates extinction formation.

(A and B) Blue light shone on ChR2-AAV–expressing vmPFC axons in the amygdala during full (50-trial) extinction training (A) did not change freezing during training or subsequent (light-free) retrieval (B). (C and D) Light shone during partial (10-trial) extinction training (C) decreased freezing during (light-free) retrieval (D). (E and F) Light shone during retrieval [after partial (10-trial, light-free) extinction training] (E) did not alter freezing (F). For virus expression and optical fiber locations, see Fig. 1, A, H, and I. Extinction trial-block = 5 CS (conditioned stimulus) presentations.