Fig. 2.

Lever responses in the reinstatement test sessions (n=9–10). The test sessions were performed 1 day after completion of extinction that followed 30 daily 1-h self-administration/conditioning training. Responses on the active lever resulted in presentation of the nicotine cue without delivery of nicotine (saline substitution). The number of responses is presented as the mean ± SEM. *p<0.05, **P<0.01 different from corresponding extinction. ⁺p<0.05, ⁺⁺P<0.01 different from saline group