Term
| Movements of the eyes are produced by extra-ocular or intra-ocular muscles? |
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Definition
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Term
How many extra-ocular muscles are there?
How many intra-ocular muscles are there? |
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Definition
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Term
| Accommodation and pupillary responses are produced by extra-ocular or intra-ocular muscles? |
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Definition
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Term
| What muscle is responsible for adduction (towards the midline/nose)? |
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Definition
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Term
| What muscle is responsible for abduction (away from midline/nose)? |
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Definition
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Term
What muscle is responsible for elevation?
depression? |
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Definition
superior rectus
inferior rectus |
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Term
What muscle is responsible for intorsion?
extorsion? |
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Definition
superior oblique
inferior oblique |
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Term
What muscle is responsible for positive accommodation (focus for near); acts against suspensory ligaments?
What is the antagonist to this muscle? |
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Definition
ciliary muscle
no antagonist muscle |
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Term
What muscle is responsible for pupilloconstriction?
What is the antagonist to this muscle (pupillodilation)? |
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Definition
sphincter pupillae iris muscle
dilator pupillae iris muscle |
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Term
True or false:
Except for changes in viewing distance, normal eye movements are yoked. |
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Definition
True
Yoking: the eyes move the same amount in the same direction.
Vertical eye movements are normally always yoked. |
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Term
| Projections from the abducens nucleus to medial rectus motoneurons by way of the ______________ provides the basis for horizontal yoking |
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Definition
| medial longitudinal fasciculus |
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Term
Eye movements stabilize the image of the external world on the _______
Eye movements bring images of objects of interest onto the _______ |
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Definition
involuntary - Eye movements stabilize the image of the external world on the retina
voluntary - Eye movements bring images of objects of interest onto the fovea |
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Term
What class of eye movement holds images of the seen world steady on the retina during brief head rotations?
voluntary or involuntary? |
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Definition
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Term
What class of eye movement holds images of the seen world steady on the retina during sustained (slow) head rotation?
voluntary or involuntary? |
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Definition
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Term
What class of eye movement holds the image of a small moving target on the fovea; with optokinetic responses, aids gaze stabilization during sustained head rotation (ex: tracking a laser)?
voluntary or involuntary? |
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Definition
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Term
What class of eye movement brings images of objects of interest onto the fovea (ex: reading)?
voluntary or involuntary? |
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Definition
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Term
What class of eye movement moves eyes in opposite directions so that images of a single object are placed or held simultaneously on both foveae (to look at objects further or nearer than you are currently looking)?
voluntary or involuntary? |
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Definition
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Term
| What class of eye movement focuses images on the fovea? |
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Definition
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Term
| What class of eye movement controls illumination levels of retina? |
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Definition
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Term
| When you turn your head in one direction with a certain velocity, what causes your eyes to turn with an equal velocity in the opposite direction? |
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Definition
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Term
If a person turns their head in one direction with a certain velocity and their eyes turn with an equal velocity in the opposite direction, what is the VOR gain?
If the eyes only turn half way, what is the VOR gain? |
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Definition
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Term
| After turning your head and your eyes have turned to a new position, what keeps the eyes in that position so it does not drift back to primary position? |
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Definition
| a tonic signal proportional to the integral of the eye velocity signal is generated and sent to the extra ocular motoneurons to maintain the new eye position |
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Term
Which of the following scenarios would cause the vestibular system to stop responding (causing nystagmus)?
rotation in darkness
rotation in light
no rotation. optic flow. |
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Definition
| rotation in darkness (vestibular but no optokinetic) |
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Term
Which of the following scenarios would the vestibular system respond?
rotation in darkness
rotation light
no rotation. optic flow. |
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Definition
rotation in light (vestibular and optokinetic)
no rotation. optic flow (optokinetic but no vestibular) |
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Term
| What eye movement is very fast and ballistic (one it starts it goes to completion) and used to see anything interesting? |
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Definition
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Term
| What is required to produce the transient force needed to move the eye rapidly despite viscous drag? |
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Definition
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Term
| What is required to hold the eye in a new position despite the elastic forces that try to return it to primary position? |
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Definition
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Term
| Where are the horizontal saccades generated? |
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Definition
| paramedian pontine reticular formation (PPRF) |
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Term
| Where are the vertical saccades generated? |
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Definition
| rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) |
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Term
| Where are oblique saccades generated? |
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Definition
| from both horizontal (PPRF) and vertical (riMLF) |
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Term
| What are the 3 neurons in the PPRF? |
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Definition
burst neurons (motor)
neural integrator (motor)
omnipause neuron |
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Term
| Which PPRF neuron is for horizontal and vertical eye movement and generate a burst of activity seen in the motor neurons? |
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Definition
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Term
| Which PPRF neuron takes the transient signal and turns it into a tonic signal to hold the eye in a new position? |
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Definition
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Term
| Which PPRF neuron continuously fires and only closes when there is a saccade (controls saccade) |
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Definition
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Term
| What neuron would you expect there to be a problem in if a person keeps making saccades back to back? |
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Definition
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Term
| What is the pre-motor area that controls contralateral saccades in 2D (amplitude and direction in contralateral visual field)? |
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Definition
| superior colliculus (projects to the PPRF) |
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Term
In the superior colliculus motor map, where would you find small saccades?
Large saccades?
Upward saccades?
Downward saccades? |
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Definition
anterior
posterior
medial
lateral |
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Term
| Does the superior colliculus control the lateral or contralateral side? |
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Definition
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Term
| What part of the brain is involved with triggering the saccade? |
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Definition
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Term
| What part of the brain is involved in saccade generation? |
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Definition
| frontal eye field (frontal cortex) |
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Term
| By being able to remember targets or make your eyes move in the opposite direction of the visual stimulus (anti-saccade), what part of of the brain is involved in this? |
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Definition
| frontal cortex (and other areas of the brain) |
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Term
| What part of the brain is involved with matching the pulse and step of the dynamic and static components of eye movements so that they don't overshoot or undershoot (makes sure saccades are right size, speed, and doesn't drift at the end) |
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Definition
| cerebellum (as with limb movements) |
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Term
| What eye movement is used for tracking a slow visual target (can't go past 100 degrees/sec)? |
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Definition
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Term
| What part of the brain is involved in controlling smooth pursuit eye movements by predicting where a visual target will go? |
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Definition
| frontal eye field (frontal cortex) |
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Term
| What is the early visual area that is sensitive to target motion in the temporal cortex in humans? |
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Definition
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Term
| What must you turn off a little when smooth pursuing an object across a background? |
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Definition
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Term
| When you change from far viewing to a near target, what 2 things happen? |
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Definition
accommodation (lens focus) and convergence
to reduce blur and disparity signals |
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Term
| When a person becomes presbioptic, can they no longer converge, accommodate, or both? |
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Definition
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Term
| Where are the cells involved in controlling convergence and divergence and focusing of the lens? |
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Definition
| oculomotor nucleus (not paramedian fontine reticular formation) |
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Term
| If the medial rectus muscle will no contract for any type of eye movement, including convergence, is it damage to the mlf or damage to the medial rectus motor neurons? |
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Definition
| medial rectus motorneurons |
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Term
| If the individual has an inability to contract the medial rectus of one eye of Adduction issues, for everything except convergence, is it damage to the mlf or damage to the medial rectus motor neurons? |
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Definition
| mlf = internuclear opthalmoplegia |
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Term
| Is it a direct or consensual response when you shine a light in one eye you get pupil constriction in that eye? |
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Definition
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Term
| Is it a direct or consensual responsone when you shine a light in one eye, the other pupil constricts equally? |
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Definition
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Term
| What is it called when pupils are not the same size? |
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Definition
| anisoscoria (can be normal but bad if it's sudden onset) |
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Term
Is this an afferent or efferent defect?
PUPILS APPROX. EQUAL IN SIZE. BUT RESPONSE TO LIGHT IN ONE EYE IS LESS THAN THE RESPONSE TO LIGHT IN THE OTHER EYE. |
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Definition
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Term
Is this is an afferent or efferent defect?
PUPILS MAY BE OF DIFFERENT SIZES (ANISOCORIA). PUPIL OF ONE EYE REACTS MORE TO LIGHT IN EITHER EYE THAN THE PUPIL OF THE OTHER EYE TO LIGHT IN EITHER EYE. |
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Definition
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Term
| In an afferent defect, where would the damage be? |
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Definition
| in the retina, the optic nerve, the optic tract, or the retinal recipient areas of the brain |
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Term
| In an efferent defect, where would the damage be? |
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Definition
| in pre-ganglionic, ciliary ganglion, post-ganglionic fibers going to iris |
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Term
True or false:
anisoscoria is an efferent deficit in the parasympathetic system only. |
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Definition
False
You can get this anisoscoria either because of efferenct deficits in the parasympathetic system, or in the sympathetic system. |
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Term
True of false:
Efferent deficits are usually characterized by an anisoscoria, independent of which eye you shine the light in. |
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Definition
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Term
| When testing for efferent deficit, is the sympathetic or parasympathetic response quicker/light driven? |
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Definition
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Term
| Is anisoscoria only caused efferent deficits? |
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Definition
| No- in tonic conditions, that the normal sympathetic input that normally dilates the pupil in one eye has been damaged and that pupil will then be a little more tonically constricted. |
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Term
| Which eye movement is an adaptive response to the slip of the image of the outside world on the retina that occurs when VOR gain is not 1.0? |
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Definition
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Term
| What neurons mediate the optokinetic response as well as indirectly modulate vestibular neurons? |
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Definition
| pretectum and medial superior temporal region of cortex |
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