Dopamine modulates neuronal activities related to motor performance in the monkey prefrontal cortex.

Effects of iontophoretically applied dopamine were investigated in prefrontal neurons of the monkey which showed activity changes during a visual reaction time task. The task consisted of an initial waiting phase (3.0 s), a warning phase (green lamp, 1.5-3.5 s), a lever-release GO phase (red lamp) and a reward phase. The neurons (n = 99) showed their activity changes during the warming (n = 31), GO (n = 43) or reward (n = 25) phase. Among those, dopamine predominantly influenced the GO phase-related activities (39/43) and the activity changes were enhanced by dopamine. Further, fluphenazine attenuated the GO phase-related activity changes. Results suggest that prefrontal dopamine may be involved in modulations of neuronal activities related to motor performance.