Basic principles of generating horizontal saccades
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Saccades are one of 5 types of eye movements. They are used to point your fovea quickly from one object of interest to another, such as the words of this sentence.
The command for a saccade begins in a structure called the Paramadian Pontine Reticular Formation; the PPRF
- Burst neurons in the PPRF generate phasic movement command which is proportional to velocity
- Tonic neurons in prepositus hypoglossi
(PPH)
- converts the phasic command to a tonic command
- this is like an integrator which converts velocity to position
- Motorneurons (MN's)
combine phasic and tonic commands
- this contracts muscles
- quickly rotates the eyes (phasic component)
- & then holds (tonic component) them there against the elastic restoring forces.
