Figure 7.

Central administration of NPY before extinction training decreased overall startle amplitude but not percentage fear-potentiated startle. A, Animals were implanted with intracerebroventricular cannulae 7–10 d before behavioral training. 30 min before extinction training, vehicle or 10 μg of NPY was infused. Animals were tested 48 h later with no drug onboard (Post-Ext). B, There was no significant difference in percentage fear-potentiated startle between the vehicle and NPY groups (values shown represent average of first five trials of test). C, We observed an overall decrease in startle amplitude and a significant decrease in NA startle values in the NPY group during the Post-Ext test [significant main effect of treatment (F _(1,35) = 4.902, p < 0.05); error bars indicate ±SEM; *p < 0.05].