First evidence of a delay-dependent working memory-enhancing effect of modafinil in mice

This study investigated the effects of pretest injection of modafinil on delayed spontaneous alternation rates (SA) used to evaluate working memory in C57 Bl/6 mice. In a first experiment, systemic modafinil at 64 mg/kg, but not at 8 mg/kg or 32 mg/kg doses produced a significant increase of alternation scores (intertrial interval (ITI) 60s) when compared with controls. In a second experiment, modafinil (64 mg/kg) enhanced the alternation rates mainly at long (60 s and 180 s) but not at short (5 s) ITIs. Exploratory latencies and activity in a four hole-board apparatus were not modified by modafinil administration. These experiments are the first to demonstrate a delay-dependent working memory-enhancing effect of modafinil.