2.8. Passive Avoidance Test

The passive avoidance test provides an indication of short-term learning and memory. This test (Med Associates Inc., St. Albans, VT, USA) consisted of three sessions. Illuminated (20 × 20 × 25 cm) and dark (20 × 20 × 25 cm) compartments were separated by a sliding door. Each rat was placed on the safe platform for training trials. The time taken for the rat to enter the dark compartment was measured. After training, when the rat entered the dark compartment, the door closed automatically and a single inescapable scrambled foot shock (0.8 mA, 3 s) was delivered through the grid floor. During the final session, the procedure was repeated until the latency to enter the dark box was ≥300 s.