Reversal by L-Dopa of Impaired Learning Due to Destruction of the Dopaminergic Nigro-Neostriatal Projection

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Science  13 Sep 1974:
Vol. 185, Issue 4155, pp. 960-962
DOI: 10.1126/science.185.4155.960


Rats receiving bilateral stereotaxic injections of 6-hydroxydopamine into the zona compacta of the substantia nigra failed to learn a one-way active avoidance response. Small doses of L-dopa (1.5 milligrams per kilogram of body weight) in combination with a peripheral decarboxylase inhibitor reversed this impairment. Animals with lesions which acquired the avoidance response during L-dopa administration retained this response when drug treatment was discontinued. These experiments suggest that the dopaminergic nigro-neostriatal projection serves a critical function in the acquisition of learned instrumental responses.