Figure 2

Protocol for associative fear conditioning. Male C57BL/6 mice are subjected to this 3 d paradigm at 6 wks post-surgery. For familiarization (d 1), each animal is exposed to Chamber A for 10 min. For training (d 2), the mouse is conditioned with five pairings of tone CS (20 s, 5 kHz, 80 dB) that coterminates with a foot-shock US (1 s, 1 mA) in Chamber A. For the context test (d 3), the animal is placed in Chamber A for 10 min. For the tone test (d 3), the mouse is placed in Chamber B, in which it received five tones (20 s, 5 kHz, 80 dB).