Facilitation of saccadic eye movements by postsaccadic electrical stimulation in the primate caudate.
Sensorimotor experience followed by positive feedback leads to motor learning. Although the striatum, an input channel of the basal ganglia, has been implicated to play a key role in motor learning, little is known about how reward information modulates the neuronal processes in the striatum that causes behavioral changes. Here, we report that direct manipulation of the neuronal signal in the primate caudate yields behavioral changes comparable with those induced by natural reward. Electrical stimulation in the oculomotor region of the caudate immediately after saccades to a fixed direction led to selective facilitation of saccades in that direction. The facilitation remained even after stimulation was stopped, indicating a plastic change. These effects were observed when stimulation was applied after, not before, saccades. We propose that the caudate plays a causal role in behavioral changes by integrating selective sensorimotor and reward information in a temporally specific manner.
Nakamura
Kae
K
Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892-4435, USA. kae@physiology.wisc.edu
Hikosaka
Okihide
O
D000818:Animals; D002421:Caudate Nucleus / Q000502:physiology*; D003342:Corpus Striatum / Q000502:physiology; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D008253:Macaca mulatta; D010775:Photic Stimulation / Q000379:methods*; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012438:Saccades / Q000502:physiology*; D013997:Time Factors