Ocular Motor Control Flashcards
The pathway that starts in the frontal eye fields, through the internal capsule to end in the paramedian pontine reticular formation controls _
Saccadic eye movements (Crosses midline)
The pathway that starts in the posterior parietal lobe to end on the ipsilateral paramedian pontine reticular formation controls _
Pursuit eye movements
The goal of eye movements is to maintain objects focused on _, which has the highest concentration of _
Fovea
Cone receptors
In general, horizontal ey movements are controlled by the _ while vertical eye movements are controlled by _. What are the nuclei?
Pons (PPRF)
Midbrain (riMLF)
Vergence movement (convergence and divergence) involves what muscles and what part of the brain?
Medial Rectus
Midbrain
Occulovestibular eye movements serve to _
Move eyes in the opposite direction from head to maintain focus / gaze
A type of eye movement that uses the same pathway as saccades but gets inputs from different structures is . Where does this input originat?
Occulo-vestibular movements
Semi-circular canals, VIII CN and VIII nucleus (crosses) to CN 3,4,6
A second more complex vestibulo-occular pathway consists of _ (3)
Reticular formation, interstitial nucleus of Cajal and cerebellum
The MLF allows connections between _ (2 connections)
Nucleus of 6 to contralateral CN3
Nucleus of 8 to contralateral CN6
Vestibulo-occular pathway integrity can be tested with _
Doll’s head maneuver (oculocephalic manuever)
The saccdic eye generator is _
PPRF
A supra-nuclear disorder (e.g. frontal eye field damage) will a cause _
Loss of voluntary gaze
Reflex gaze intact
Another word for vestibulo-occular reflex is _
Occulo-cephalic reflex
What is the effect of internuclear opthalmoplegia?
Ipsilateral medial rectus paresis (Complete MR block)
Contralateral nystagmus with abduction (Partial LR block)
Dorsal midbrain syndrome (Parinaud’s syndrome) involves a lesion in _
Posterior commissure
4 symptoms of parinaud’s syndrome are _
Loss of upgaze
dissociation of pupillary light reflex
convergence-retraction convergence
lid retraction
A lesion to nucleus of CN3 leads to _
Ipsilateral paresis of innervated muscles
Additionally, contralateral paresis of SR
Ptosis
Likely bilateral findings because lesion on midline
A lesion to nucleus of CN4 leads to _
Contralateral SO paresis
A lesion to nucleus of CN6 leads to _
Paresis of conjugate horizontal gaze to ipsilateral side (Blocks both LR and MR)
CN3 lesion leads to _
Down and out
Ptosis
Dialated / unresponsive pupil
A PCA aneurism can cause _
3rd nerve palsy
CN4 lesion leads to _
Eye deviated up (hypertropia)
CN6 lesion leads to _
Eye deviated in (esotropia)
In patients with MLF syndrome, why is convergence normal?
Because the cortex directly innervates the CN3 (MR) nucleus for both eyes. MLF if bypassed
