Contextual and cued fear conditioning were performed as previously described28,51,52. For contextual fear conditioning, a single 2sec, 0.70mA scrambled footshock was given in at 2:28 of a 3:00min training period followed by a 5min testing period 24 hrs later. For cued fear conditioning, animals were in the chamber for two minutes followed by a 30sec tone that co-terminated with a 2sec, 0.70mA scrambled footshock. Animals were allowed to remain in the chamber for an additional 30sec. Twenty-four hours after conditioning, animals were tested in a novel context (2min) followed by a 3min tone. Freezing behavior was measured using EthoVision 3.1 (Noldus Information Technology).51
