Average incidence of biting, vocalizations, and circling during handling at a weanling age after MK-801 neonatal treatment with 0, 0.025, 0.05, 0.1, 0.15, 0.2, or 0.25 mg/kg. Circling was only found at doses above 0.15 mg/kg. Biting was significantly higher at 0.15 mg/kg.