Improvement of learning processes following chronic systemic administration of modafinil in mice

This study was aimed at determining the effects of a chronic modafinil intraperitoneal administration on the rate of learning in a series of five serial spatial discrimination reversals (SSDR) in a T-maze. Results showed that a daily modafinil administration at 64 mg/kg but not at 32 mg/kg induced a faster learning rate as compared to controls. This learning improvement in experimental mice was due to the faster emergence of a win-stay rule over days of testing. In contrast, a second experiment showed that the same modafinil treatment had no significant effect on contingently reinforced alternation rates over five successive days of testing, as compared to controls. Thus, the results show that modafinil spared the ability to shift responses over trials and consequently, that the use of the win-stay rule to solve the SSDR task observed in modafinil-treated animals is due to an improvement of learning processes. (C) 2002 Elsevier Science Inc. All rights reserved.