Fig. 1.

IL-PFC stimulation is necessary and sufficient for the antidepressant behavioral actions of ketamine. (A–C) Neuronal silencing by muscimol infusion (1.25 µg per side) into the IL blocks the effects of ketamine (10 mg/kg, i.p.) in the FST (B) and NSFT (C). Immobility times in the FST or the latency to eat in NSFT are shown as the mean ± SEM (n = 4–10 per group). *P < 0.05, compared with PBS + Sal; analysis of variance (two-way or one-way ANOVA with LSD post hoc test). (D–F) Ketamine microinfusions into the IL produce an antidepressant response in the FST (E) and an anxiolytic effect in the NSFT (F). Doses of 10 and 30 ng per side produced a significant response in the FST, and the 10-ng dose was used for subsequent studies in the NSFT. Means are derived from 4–8 rats per group. *P < 0.05, compared with PBS; analysis of variance (one-way ANOVA with LSD post hoc test) or independent t test (C, E, and F). Ket, ketamine; Mus, muscimol; Sal, saline.