Attentional performance of C57BL/6 and DBA/2 mice in the 5-choice serial reaction time task.

C57BL/6 and DBA/2 were compared in the 5-choice serial reaction time task for differences in performance related to attention and impulsivity. The goal was to examine behavioural processes in mice that may relate to ADHD in humans. Groups of male mice were trained to nose-poke in response to a stimulus light presented randomly in one of five holes; correct responses were reinforced with food. During training the stimulus duration (SD) was reduced progressively from 60 to 0.5s. The C57BL/6 and DBA/2 mice did not differ during early stages of training when attentional demands were low (SD of 60, 10 or 5s). As task demands increased, strain differences emerged; C57BL/6 mice were more accurate than DBA/2 mice with stimuli of 2, 1 and 0.5s. DBA/2 mice also made more anticipatory (impulsive) responses during inter-trial intervals than C57BL/6 mice at SD of 5, 2, 1 and 0.5s. The ability to carry out the task was present in both strains of mice but they differed significantly in the levels of performance that were achieved. It is argued that the differences in accuracy and anticipatory responding were closely related and that the primary difference between the strains may be in impulsivity.