Neuroscience Oculomotor Function Michael L. Vertino Flashcards
What are movements that bring objects of interest to the fovea called?
Saccades
What eye movements change the plane of focus?
Vergence and accomodation
What eye movements steady the scene against movement?
Vestibular-ocular reflex (VOR) and (OKN)
The scene, deciding what saccades are needed, happens in what part of the brain?
Diencephalon, forebrain
The generation of saccades happens in what part of the brain?
Brainstem (ish)
Where is the vertical saccade generator?
Midbrain
Where is the horizontal saccade generator?
At junction of pons and medulla
What nuclei are located in the medulla?
Vestibular
What is oculomotor apraxia? What nuclei remains intact?
You move your head because you can’t move your eyes. Probably a 3 and 6 issue. Vestibular nuclei remains intact.
- -Absence of fast phase nystagmus on horizontal optokinetic testing
- -Problems in nerve function involved in eye movement control, called neuropathy
- -Inability to visually follow objects
- -Head thrusts to compensate for the inability to accomplish voluntary horizontal gaze
What happens in the pterygopontine reticular formation (PPRF)?
6 and 3 come together
What is left CN VI palsy?
Weakness of left cn 6. Eye turned inwards, double vision, other symptoms possible depending on where lesion is
Where are the inhibitory bursters, traveling from horizontal premotor areas in the pons to the CN VI nucleus?
Medulla
What occurs in internuclear ophthalmoplegia?
Convergence OK Slow adduction to one side Lesion of the MLF Nystagmus when eye abducts Can be bilateral or not
What causes slow saccades?
Lose burster activity, partial burster loss
If the integrator of burst information in the cerebellum is damaged, what symptoms are seen?
Nystagmus, no ability for tonic response and holding that response, thus in double nystagmus, eyes can’t hold position
