Effects of microinfusion of lidocaine into the MT on the initial and retention latencies tested in the inhibitory avoidance task. a. Illustration of infusion cannula placements (arrow) in a histological section of the medial thalamus. Placements shown are from all rats included in the final analysis (MT-pretest-lidocaine, filled inverted triangles; MT-posttraining-lidocaine, open squares). b. Lidocaine infusion into the MT immediate after behavioral training disrupted retention of inhibitory avoidance learning conducted 24 h later. Fisher's LSD test showed a significant difference between posttraining infusions of saline and lidocaine in the MT group in the 24 h retention test (**p < 0.01). c. Lidocaine infusion into the MT immediately before the 24 h retention test had no effect on the retention of inhibitory avoidance learning tested 24 h later.