Fig. 3.

Cocaine is a more efficacious reinforcer in ClockΔ19 mice than in WT mice. a Cocaine infusions earned in an FR1 descending dose–response schedule. b Dose–response lever discrimination (mean number of active and inactive lever presses). Open bars denote ClockΔ19 mice active lever presses, bars with vertical lines denote ClockΔ19 mice inactive lever presses, gray bars denote WT mice active lever presses, and checkered bars denote WT mice inactive lever presses. Open circles denote ClockΔ19 mice and gray squares denote WT mice. N=7/genotype