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Eye movements induced by pontine stimulation: interaction with visually triggered saccades
D L Sparks1, L E Mays, J D Porter
1Department of Physiology and Biophysics, University of Alabama at Birmingham 35294.
Journal of Neurophysiology
|August 1, 1987
Summary
Rhesus monkeys demonstrated how the brain controls eye movements. Stimulation of the brainstem revealed insights into the saccadic system
Area of Science:
- Neuroscience
- Ophthalmology
- Systems Neuroscience
Background:
- The saccadic system is responsible for rapid eye movements.
- Models of the saccadic system rely on feedback mechanisms for eye position.
- Understanding these mechanisms is crucial for explaining eye movement control.
Purpose of the Study:
- To investigate the neural basis of the saccadic system in rhesus monkeys.
- To test the validity of current models of eye movement control.
- To explore how the brain compensates for unexpected perturbations during saccade generation.
Main Methods:
- Rhesus monkeys were trained to fixate on visual targets.
- Microstimulation of the paramedian pontine reticular formation (PPRF) was used to perturb eye position.
- The resulting eye movements and compensatory saccades were analyzed.
Main Results:
- Stimulation at most PPRF sites resulted in compensatory saccades to the visual target.
- Stimulation at other PPRF sites failed to elicit compensatory saccades, suggesting stimulation beyond the eye position signal origin.
- Pontine stimulation could prematurely trigger saccades, with timing dependent on target presentation and stimulation interval.
Conclusions:
- Data suggest that input signals for saccade generators develop gradually.
- Current models, like Robinson's, partially explain compensation, but modifications are needed to account for all findings.
- Modified models incorporating separate neural integrators may better explain compensation and failure to compensate, though kinematic considerations remain.