EFFECT OF THE NIGROSTRIATAL DOPAMINE SYSTEM ON ACQUIRED NEURAL RESPONSES IN THE STRIATUM OF BEHAVING MONKEYS

Dysfunction of the nigrostriatal dopamine system results in marked dis orders of movement such as occur in Parkinson's disease. Functions of this dopamine-containing projection system were examined in monkeys tr ained in a classical conditioning task, and the effects of striatal do pamine depletion were tested. Unilateral dopamine loss substantially r educed the acquired sensory responsiveness of striatal neurons monitor ed electrophysiologically. This effect was ipsilateral and selective, and could be reversed by apomorphine. These results suggest that the p rimate nigrostriatal system modulates expression of neuronal response plasticity in the striatum during sensorimotor learning.