A two compartment passive avoidance apparatus was utilized; one illuminated box with floor grids and a second dark box with an electrified floor that can be connected to a shock source. After the rat entered with all four limbs into the dark compartment, an electric footshock was automatically delivered. The "Passive Avoidance Training Time" gives the latency before the rat entered the dark compartment first . One day later, the test was repeated. "Passive Avoidance Retention Time" indicates the time that a rat refrained from entering the dark compartment. The test was terminated after 300 seconds.