Fig. 3.

LBN Decreases Cocaine Hedonic Set Point, without Affecting Other Cocaine-Seeking Behaviors: A) Self-administration acquisition data is shown, averaged across the first three days of FR1 self-administration training, and the last three days of training. Control rats are represented with black lines, LBN animals in orange. At left, active lever presses are shown with solid lines, inactive lever presses are represented with dashed lines. At right, number of cocaine infusions/session are shown with dotted lines. *p < .05, interaction of training block (first three vs. last three) and LBN/control group, group mean ± SEM is represented. B) Self-administration by rat: Number of cocaine infusions self-administered by individual rats (thin lines) on each of the first 10 days of training. Group means and SEM are shown with thick lines. Black = control, orange = LBN. C) Behavioral economics: Motivation to maintain preferred cocaine levels (demand elasticity; α) is represented for control (black) and LBN (orange) rats. Hedonic set point (Low-effort preferred intake level, extrapolated for zero cost: Q₀) is also shown for control and LBN rats (Bentzley et al., 2013). *p < .05, control vs. LBN. D) Example demand curves: Effects of cost (lever pressing required to obtain 1 mg cocaine; x axis) on consumption (average cocaine self-administered per cost, binned over 7 days of stable economic testing; y axis) are shown for individual control (black circles and curves) and LBN rats (orange circles/curves). Q₀ and α values are shown for these representative rats. E) Self-administration dose-response: Number of cocaine infusions self-administered by control and LBN rats are shown for low, medium, or high doses. F) Reinstatement: Active lever presses (AL; solid bars, and circles representing individual rats), cue presentations (dashed border bars), and inactive lever presses (grey bars) are shown for control and LBN rats in late extinction training (late ext), cue-induced reinstatement, and cocaine-primed reinstatement tests. In panels C, E, & F, bars represent mean (±SEM), and individual rats' data are represented with circles. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)