Figure 2.

Effects of subanesthetic IV ketamine infusion on fear memory retrieval, extinction, and renewal in female rats. (A) Ketamine infusion increased cued fear memory retrieval with all three doses (2, 10, and 20 mg/kg, 2 h). (B) Ketamine infusion impaired fear extinction retrieval in female rats. Each Block consists of average freezing of two consecutive auditory tone (CS) presentations. (C) Higher doses of ketamine (10 and 20 mg/kg) increased contextual fear memory when animals were tested in the conditioning chamber (context A). (D) Higher doses of ketamine (10 and 20 mg/kg) increased cued fear memory renewal (context A) after two sessions of cued fear extinction (context B). * p < 0.05 compared to saline controls.