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
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 ___
the ___ decides where saccades should go
Vergence and Accomodation. Adjust the
plane of focus
___ Eye Field controls voluntary eye movements
___Cortex controls involuntary pursuit movements
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
with oculomotor apraxia cant _____ but can ____
can’t “look right” on command but can still follow a finger to the right
Internuclear Ophthalmoplegia = ___ lesion.
with ___ lesion R. eye will not adduct when asked to look left voluntarily, but can move when
following a finger
sx of CN 6 palsy
the eye can’t move laterally, either voluntarily or involuntarily
A saccade requires (2)
1. both a “burst” of firing to overcome inertia and initiate eye movement
2. a new “tonic” firing rate to maintain the new position:
Motor Error: difference between ___ and ___
field and where you want to look
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
Partial Burster Loss (damage to medulla) results in what sx
Loss of Cerebellar Integrator causes what dsx
can look R. or L, but
can’t hold the new position.
foveal pursuit involves keeping the object on the fovea.
what is moving.. the head or the eyes?
the eyes are moving
bilateral oipthalmoplegia.. only one of the things that is nml is ___
pursuit movements use the
the eye moving ___
will be slow
adducting the eye is slow... always going to be
problem with burst cell position
slowed saccades, might not hold position
problem with integrator
what would result?
new tonic firing rate wouldnt be there
so it would drift back
but wont hold
with cerebellar disease
problem with integrator results from damage to the
loss of pause cells results in