Oculomotor Lec26 Flashcards
(34 cards)
purpose of the Vestibular Ocular Reflex.
steady the scene against movement
keep focus on object
Vestibular Ocular Reflex. The eyes move ___ of how the head moves to
keep focus on an object
opposite
purpose of OptoKinetic Nystagmus
. The eyes can jump focus
ex. switching targets as we
walk - also steadies the scene against movement
Saccades. Fast eye movements to shift the visual scene onto the ___
fovea
the ___ decides where saccades should go
forebrain
Vergence and Accomodation. Adjust the
plane of focus
___ Eye Field controls voluntary eye movements
Frontal
___Cortex controls involuntary pursuit movements
Superior Parietal
Vertical gaze center/saccade generator is in the
midbrain, near CN 3 and 4
Horizontal gaze center is in the
PPRF (paramedian pontine reticular formation), near CN 6
The MLF, medial longitudinal fasciculus, gets both eyes to move together by activating the
contralateral CN 3
Oculomotor Apraxia = lesion to
frontal eye fields
Oculomotor Apraxia leads to loss of
voluntary eye movements
___ is preveserved with oculomotor apraxia
VOR
with oculomotor apraxia cant _____ but can ____
can’t “look right” on command but can still follow a finger to the right
Internuclear Ophthalmoplegia = ___ lesion.
MLF
with ___ lesion R. eye will not adduct when asked to look left voluntarily, but can move when
following a finger
MLF
sx of CN 6 palsy
the eye can’t move laterally, either voluntarily or involuntarily
A saccade requires (2)
- both a “burst” of firing to overcome inertia and initiate eye movement
- a new “tonic” firing rate to maintain the new position:

Motor Error: difference between ___ and ___
current visual
field and where you want to look
baby
whose eyes kept moving was
Opsoclonus = Loss of frontal lobe Pause cells..
Opsoclonus = Loss of___
frontal lobe Pause cells..
Partial Burster Loss is due to damage to the
medulla
Partial Burster Loss (damage to medulla) results in what sx
slowed saccades


