Gene-dose dependent effects of methamphetamine on interval timing in dopamine-transporter knockout mice

► Wild-type and dopamine transporter (DAT) knockout mice are studied using dual (15-s and 45-s) and single (20-s) peak-interval timing procedures. ► We examine changes in interval timing as a function of DAT gene deletions. ► DAT −/− mice were unable to exhibit temporal control of lever pressing, while DAT +/− mice were able to time in a manner similar to DAT +/+ mice unless challenged with methamphetamine injections. ► Observations are discussed in terms of hyperdopaminergic effects in cortical-striatal circuits.