Fig. 1: Experiment 1 results.
From: Demand for heroin in rats: effects of non-drug alternative substitutes and complements
a Demand curves fit to group mean consumption of heroin infusions (IHS transformed) across the prices (fixed ratios) for heroin on the right lever. The dotted vertical line represents the FR-6 price for TOA reinforcers or left-lever heroin infusions always available to rats in the TOA Alternative and Heroin Alternative groups, respectively. b Mean (±SEM) essential value for each of the three groups. Circles and triangles represent individual female and male rats, respectively. **p < 0.01. c Mean (±SEM) heroin Q0. d Mean (±SEM) consumption of left lever reinforcers as a function of the price of heroin on the right lever. The dotted vertical line represents the FR-6 price for left-lever reinforcers. For the No Alternative group, “reinforcers” where the number of left-lever responses divided by 6. e Mean (±SEM) of the slopes of the linear regression best fit lines relating log left-lever reinforcer consumption to log price of heroin on the right lever. The dashed horizontal line at 0.2 represents the threshold for identifying substitutes. *p < 0.05, ***p < 0.001.
