Activation of β-adrenoceptors in the BLA, but not the hippocampus, is required for enabling corticosterone effects on object recognition memory. Data represent discrimination index (%) on a 24-h retention trial, expressed as mean ± SEM. (A and B) Diagram and photomicrograph illustrating placement of infusion needle tip in the BLA and hippocampus. The arrow points to the needle tip. (C) Effect of posttraining administration of the β-adrenoceptor antagonist propranolol (0.5 μg per hemisphere) into the BLA on corticosterone-induced enhancement of object recognition memory in nonhabituated rats. ∗∗, P < 0.0001 vs. vehicle (n = 8–11 per group). (D) Effect of posttraining administration of the β-adrenoceptor antagonist propranolol (1.25 μg per hemisphere) into the hippocampus on corticosterone-induced enhancement of object recognition memory in nonhabituated rats. ∗, P < 0.05; ∗∗, P < 0.0001 vs. vehicle (n = 10–14 per group).