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. Author manuscript; available in PMC: 2013 Nov 16.
Published in final edited form as: Behav Neurosci. 2009 Apr;123(2):10.1037/a0014592. doi: 10.1037/a0014592

Figure 1. Acquisition of cocaine self-administration.

Figure 1

Data represent mean responses (± SEM) on the active (black circles) and inactive levers (white circles), and the total number of cocaine infusions (± SEM; gray circles) during the cocaine self-administration training phase under FR1 and FR4 schedules of reinforcement (n = 10). Active lever responses resulted in the delivery of an i.v. cocaine infusion (0.75 mg/kg/0.1 ml) and simultaneous presentation of the cocaine-paired cues.