Figure 2.

Comparison of reinstatement responses after reversal of the SΔ cue conditions (RST 2) with responses during the self-administration training (SA), extinction (EXT), and reinstatement (RST 1) phases in rats assigned to the S⁺ (n = 5; Group 1) and S⁻ (n = 7; Group 2) conditions during the initial reinstatement tests shown in Fig. 1. (Data for the SA, EXT, and RST 1 conditions represent averages across the last 3 days of the respective phase). Responding vs. nonresponding during the reinstatement tests was reliably altered as a function of the SΔ condition (*P < 0.0001 and ⁺P < 0.01, significantly different from S⁻ and extinction responses within each respective group).