17.0 Control of Eye Movements Flashcards
Where are the burst cells, tonic cells, and pause cells located for horizontal saccadic movements?
Horizontal
Burst cells: Paramedian pontine reticular formation
Tonic cells: Nucleus prepositus hypoglossi
Pause cells: Omnipause cells of raphe nuclei
What three locations are associated with upward gaze?
Tumor of what structure can damage these?
Superior colliculus
Posteiror commissure
Pretectal area
Pineal gland tumors can damage these and result in palsy of upward gaze.
What is the key clinical difference between the vergence pathway and the other pathways of eye adduction?
The vergence pathway doesn’t use the medial longitudinal fasciculus.
If a patient can cross their eyes on vergence, but cannot adduct otherwise, MLF is damaged.
Which region of the brain performs volitional and reflexive saccades respectively?
Volitional saccades: Frontal eye field.
Reflexive saccades: Superior colliculus.
Where is the damage in intranuclear opthalmoplegia?
In the MLF in the pons and midbrain.
The right parieto-occipital junction moves the eyes in which direction during smooth pursuit?
To the right.
What are the three components of the near reflex?
Convergence of the eyes
Accomodation (lens thickens)
Pupillary constriction
Lesions of what structure can cause downward palsy?
The red nucleus.
What is Argyll-Robertson pupil?
Lack of a light reflex, but pupillary constriction on vergence.
Damages the light reflex, but spares the more ventral pupillary near reflex pathway.
Seen sometimes in tertiary syphilis.
What pathway is the rostral interstitial nucleus of the medial longitudinal fasciculus associated with?
The vertical saccade pathway.
Where are the burst cells, tonic cells, and pause cells located for vertical saccadic movements?
Vertical:
Burst: Rostral interstitial nucleus of the median longitudinal fissure
Tonic: Interstitial nucleus of cajal
Pause: omnipause cells of the raphe nuclei
What are the symptoms of internucler opthalmoplegia?
What if the damage includes the abducens nucleus?
Weak adduction on the side of the lesion.
Nystagmus in the normal eye.
Only see adduction during vergence, rather than smooth pursuit or saccades.
If the abducens nucleus is involved as well, you will lose ipsilateral abduction and contralateral adduction.
Where does the smooth pursuit pathway originate?
The parieto-occipital junction
Which frontal eye field (right or left) instructs the eyes to perform saccadic movements to the right?
The left frontal eye field.
