Fig. 3.

Rats will lever press for cues paired with cocaine during estrus. a Experimental groups: cues paired during estrus, during diestrus, or in males (n = 4–9 per group). b There was no effect of cue pairing stage on perseverative responding. c Timeline of experiments for incubation testing. d Animals were placed into the operant chamber and allowed to lever press for the presentation of a cue light one day and 30 days following self-administration. Estrus-paired cues engendered higher rates of responding at day 30. **p < 0.01 compared to male and diestrus-paired groups. e Incubation was not different between any of the groups. All data are presented as mean ± S.E.M