Effects of olanzapine and risperidone on the integrated EMG recorded from the external urethral sphincter. A) The EMG during Phase 1, which may be analogous to the "guarding reflex" was significantly decreased by olanzapine (0.1 and 1.0 mg/kg). Risperidone had no effect. B) Both olanzapine and risperidone had a significant effect on the EMG during Phase 2. Olanzapine had greater effects, essentially abolishing the bursting pattern of the EMG after 1.0 mg/kg. C) Both olanzapine and risperidone decreased the EMG during phase 3. However, olanzapine had a greater effect (0.1 and 1.0 mg/kg) than risperidone. D) The amplitude of the individual bursts of EMG observed during phase 2 were not significantly affected by risperidone. Olanzapine had no effect at 0.1 mg/kg but at 1.0 mg/kg abolished the bursting pattern.