Experimental hemiplegia in the monkey: basal ganglia glucose activity during recovery.

Unilateral ablation of cerebral cortical areas 4 and 6 of Brodmann in the macaque monkey results in a dense contralateral hemiplegia that recovers partially with time. During the phase of dense hemiplegia, the local cerebral metabolic rate for glucose (lCMRGlc) is decreased significantly in the caudate nucleus, putamen, globus pallidus, subthalamic nucleus, substantia nigra, and red nucleus of the hemisphere ipsilateral to the lesion. In the present study, lCMRGlc in the basal ganglia was studied during the phase of partial recovery of motor activity. lCMRGlc was partially restored, and the greatest degree of restoration occurred in structures with direct connections to the cerebral cortex (caudate nucleus, putamen, subthalamic nucleus, substantia nigra, and red nucleus). Restoration was least in structures that do not receive direct connections from the cerebral cortex (the internal and external segments of the globus pallidus). The findings support the hypothesis that corticofugal activity accounts for a substantial degree of functional recovery.