Fig. 1.

Schematic diagram of the experimental procedures. (A) Flow of experimental treatments. Rats were first given cannulae implantation targeted at the mPFC. After recovery, they were trained using differential fear conditioning procedure. The retention test was conducted 24 hrs after the last conditioning session. (B) Pre-conditioning vs. Pre-testing drug infusion. In Exp.1, muscimol or aCSF was infused before each conditioning session but not on the 24-hr retention test. In Exp. 2, rats were conditioned without drug infusion, and then muscimol or aCSF was infused only before the retention test. Arrows indicate drug infusion.