Figure 1.

Schematic illustration of the experimental timeline for Experiment 1 (EXP1) and Experiment 2 (EXP2), performed in different groups of rats. Asterisk represents that, after initial training on the delay discounting (DD) task, rats received seven cocaine – cocaine-paired context (COC context) and seven saline – saline-paired context (SAL context) pairings in alternation during Pavlovian conditioning. After conditioning, rats were required to re-obtain the DD stability criterion. In Experiment 1, four food-reinforced DD tests were then conducted. Bidirectional arrows indicate that, during these DD test session, the order of exposure to the two testing contexts (SAL context, COC context) and the order of intraperitoneal pretreatments (15 mg/kg of cocaine, 1 ml/kg of saline) were counterbalanced. In Experiment 2, eight food-reinforced DD tests were conducted. Bidirectional arrows indicate that, during these DD test sessions, the order of exposure to the two testing contexts, the order of intraperitoneal pretreatment types (mecamylamine, saline) and the order of mecamylamine doses (0.2 mg/kg, 2 mg/kg) were counterbalanced. Rats received additional DD task training in the training context on a minimum of two days before each test session.