Extracellular recordings were obtained from mesencephalic dopamine neurons in urethane-anesthetized rats. A population of neurons responded to electrical stimulation of the frontal cortex with bursts of action potentials. These bursts resembled those that occur spontaneously in midbrain dopamine neurons with regard to length, interspike interval and post-burst inhibition. This is the first afferent input known to elicit bursting in dopamine neurons.