Neuronal activity in the primate globus pallidus during smooth pursuit eye movements.

Although the roles of the basal ganglia in the control of saccadic eye movements have been extensively examined, little is known about their roles in smooth pursuit. Recent anatomical data suggest that, like somatic movements, smooth pursuit may also be regulated by signals through the basal ganglia thalamocortical pathways. To understand whether the basal ganglia, especially the globus pallidus (GP), could play roles in pursuit, we examined the firing of individual GP neurons when monkeys performed smooth pursuit. We found that a subset of neurons in both the external and the internal segments of the GP modulated firing during pursuit, suggesting that pathways through the GP might play roles in the control of smooth pursuit eye movements.