The effect of amphetamine on head and eye movements following vestibular stimulation in squirrel monkeys

The effect of a single dose intra-muscular injection of amphetamine sulfate on head and eye movements evoked by vestibular stimulation was investigated in squirrel monkeys. Doses injected were 0.5, 0.4, 0.3, 0.2 mg/kg, and control no injections. Amphetamine did not change the gain of vestibular evoked head and eye movements, but prolonged time constant (in function of dose) showing greater effect in eye movements. More than 0.3 mg/kg was found to be a proper dose for this species to maintain an appropriate constant alertness level for vestibular studies.