Extinction training is effective in combination with chronic Flx treatment after fear conditioning. (A) After fear conditioning and 2 weeks of Flx treatment, mice were subjected to fear renewal (protocol I) or fear reinstatement (protocol II). 5 US indicates five unsignaled foot shocks. (B) Fear renewal: Control and Flx groups (n = 10 per group) exhibited similar levels of fear acquisition and extinction. One week later, only control group showed elevated spontaneous recovery and significant fear renewal. The Flxextinction group froze less than either control-extinction or Flx–no-extinction groups (NoExt, n = 7). (C) Fear reinstatement: Although both groups exhibited increased levels of freezing when compared with the extinguished levels, the Flx group showed lower levels of fear reinstatement (P < 0.05). N = 8 per group. *P < 0.05, **P < 0.01. Error bars indicate mean ± SEM.