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. Author manuscript; available in PMC: 2010 Oct 1.
Published in final edited form as: Pharmacol Biochem Behav. 2009 May 21;93(4):375–381. doi: 10.1016/j.pbb.2009.05.008

Fig. 1.

Fig. 1

Reinforced responses for rats trained to self-administer 0.3 mg/kg/inj cocaine (Experiment 1). One response was associated with a 10-sec infusion (Fast) and the other with a 100-sec (Slow) infusion. The top panel shows the first 15 days of acquisition for 8 rats. The difference between the two responses (Fast vs Slow) was significant (p < 0.01). The bottom panel shows the reinforced responses for 5 rats during the final 5 days of acquisition and the first 5 days following the reversal of the reinforcers associated with each response. Circles represent acquisition while triangles represent reversal. Closed symbols are the fast pump responses while open symbols are the slow pump responses. While the differences between the Fast and Slow responses were significantly different for each phase (p’s < 0.01), there was no evidence of reversal. *Difference in main effect of infusion duration, p < 0.05.