Background: Few studies have investigated the effects of conventional attention deficit-hyperactivity disorder (ADHD) medication in the mouse
5-choice serial reaction time task (5-CSRTT), and rat studies have yielded inconsistent results.

Objective: We aimed to examine the effects of acute methylphenidate (MPH) and amphetamine (AMPH) treatment in the mouse 5-CSRTT.

Methods: Trained male C57Bl/6J mice were tested in a variable stimulus duration schedule. Effects of AMPH (0.25, 0.5, and 1 mg/kg) and MPH (0.5,
1.0, and 2.0 mg/kg) on discriminative accuracy, omissions, and premature responses were assessed. Saline treatment data determined high- and lowattentive (LA), and high- and low-impulsive (LI) subgroups according to the upper and lower 30th percentiles, respectively.

Results: In the LA subgroup accuracy was improved by 0.5 mg/kg AMPH and 2 mg/kg MPH, while no effect was found in the high-attentive (HA)
subgroup. Premature responses were increased by 1 mg/kg AMPH and 0.5 mg/kg MPH for all animals, and by 1 mg/kg AMPH for the LI subgroup.

Conclusions: The use of variable stimulus duration, along with the division into high- and LA, and high-and LI subgroups, may improve the sensitivity
of the 5-CSRTT when investigating drug effects on attention and impulsivity.