ACC CP-AMPA receptors are necessary for trace fear memory. (A) Immediately following trace fear conditioning, we exposed mice to bi-lateral, intra-ACC microinjections of either NASPM (3 mM, 0.5 μl/side) or saline (0.5 μl/side). (B) Learning curves. (C) (Left) When tested in a new environment 24 h later, mice exposed to intra-ACC injections of NASPM displayed significantly less freezing behavior in response to the CS (saline: n = 6; trace: n = 5, t = 2.51). (Right) Representative markers indicating microinjection locations. (* P < 0.02 ).