Metabolic mapping of the oculomotor system in MPTP-induced parkinsonian monkeys.

The quantitative autoradiographic 2-[14C]deoxyglucose method was used to map the distribution of alterations of local cerebral metabolic rate for glucose (lCMRGlc) in the oculomotor system of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-(MPTP)-induced parkinsonian monkeys. The lCMRGlc was decreased in the frontal eye fields and in the paralamellar mediodorsal thalamus in the parkinsonian monkeys as compared to normal controls. No changes in lCMRGlc were observed in other areas of the oculomotor system. L-Dopa therapy reversed the oculomotor symptoms in these monkeys, as well as the decrease of lCMRGlc in the frontal eye fields and the paralamellar mediodorsal thalamus. Because the frontal eye fields are known to be involved in the initiation of voluntary saccades, these findings suggest a functional anatomical basis for the oculomotor deficits in Parkinson's disease.