Fig. 1.

Experimental timeline. Rats were assigned to either sedentary (locked wheels) or voluntary running (mobile wheels) conditions three days prior to conditioning in Context A (Tone only rats were exposed to the auditory conditioned stimulus (CS) in each context but did not receive a foot shock on the day of conditioning). Twenty four hours later, all rats were exposed to unreinforced presentations of the auditory CS in either Context B or their familiar locked or mobile wheels. Relapse testing took place 7 days later in a novel Context C.