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. Author manuscript; available in PMC: 2013 Feb 1.
Published in final edited form as: Psychopharmacology (Berl). 2011 Aug 24;219(4):1089–1097. doi: 10.1007/s00213-011-2438-6

Figure 1.

Figure 1

Cocaine intake as a function of session or acquisition day in each group of rats, regardless of LCR/HCR classification. A Daily cocaine intake over the 14-session experiment is shown for rats self-administering i.v. cocaine (0.375 – 1.5 mg/kg) according to a fixed ratio 1 (FR1) schedule of reinforcement. B Cocaine intake is shown for the three sessions prior to and first three sessions post-acquisition in the same groups of rats as in (A). X represents the day of acquisition. N values are given in parentheses in (A) and (B). Data in (A) and (B) are mean values ± SEM. ★ p<0.05 1.5 mg/kg vs. all doses; & p<0.05 1.5 mg/kg vs. 0.375 mg/kg and 1.0 mg/kg; # p<0.05 1.5 mg/kg vs. 0.375 mg/kg. It should be noted that N values in (B) represent data for sessions X to X+3, as not all animals have data from sessions prior to X (i.e., acquisition occurred on the first session) and thus, N values are lower for those data points.