Figure 1.
Schematic illustrating the experimental design. All animals received identical Pavlovian conditioned approach (PCA) and cocaine self-administration acquisition training. Following acquisition, Experiment 1 (Exp. 1), and Experiment 2 (Exp. 2) diverged as shown. During self administration, the conditional stimulus (CS) was a nose poke port cue light and the unconditional stimulus (US) was an intravenous infusion of cocaine. Depending on the experimental phase, an active nose poke produced the CS and US (Acquisition/Re-Acquisition), the CS but no US (Cued Extinction), no CS but the US (Cue Removal), or nothing (X – Extinction).