Effects of RO5263397 (left column) and methamphetamine alone or in combination with RO5263397 (right column) on 5-CSRTT performance. Ordinates are percent accuracy (first row), omissions (second row), premature responses (third row), timeout responses (fourth row), and perseverative responses (fifth row). Abscissas are the dose of RO5263397 (left) or methamphetamine (right) in mg/kg. **P < 0.01, ***P < 0.001, ****P < 0.0001 main effect of RO5263397 treatment according to two-way repeated-measures ANOVA.