Role for subthalamic nucleus neurons in switching from automatic to controlled eye movement.
The subthalamic nucleus (STN) of the basal ganglia is an important element of motor control. This is demonstrated by involuntary movements induced by STN lesions and the successful treatment of Parkinson's disease by STN stimulation. However, it is still unclear how individual STN neurons participate in motor control. Here, we report that the STN has a function in switching from automatic to volitionally controlled eye movement. In the STN of trained macaque monkeys, we found neurons that showed a phasic change in activity specifically before volitionally controlled saccades which were switched from automatic saccades. A majority of switch-related neurons were considered to inhibit no-longer-valid automatic processes, and the inhibition started early enough to enable the animal to switch. We suggest that the STN mediates the control signal originated from the medial frontal cortex and implements the behavioral switching function using its connections with other basal ganglia nuclei and the superior colliculus.
Isoda
Masaki
M
Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA. isodam@brain.riken.jp
Hikosaka
Okihide
O
D000200:Action Potentials / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001288:Attention / Q000502:physiology*; D001522:Behavior, Animal; D003657:Decision Making / Q000502:physiology; D005133:Eye Movements / Q000502:physiology*; D007839:Functional Laterality; D008253:Macaca mulatta; D009474:Neurons / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D020531:Subthalamic Nucleus / Q000166:cytology* / Q000293:injuries; D013647:Task Performance and Analysis