Neuro: Eye Movements And Sensory Integration

Front 1

Describe/ define each clinical terminology for eyes below.

A. Diplopia
B. Dysconjugate eve movements
C. Esotropia
D. Exotropia
E. Hypertropia
F. Phorias

Back 1

A. Diplopia: double vision
B. Dysconjugate eve movements: when the two eyes move to different places
C. Esotropia: medial displacement/deviation
D. Exotropia: lateral displacement/deviation
E. Hypertropia: elevated displacement/deviation
F. Phorias:weakness only when gaze is shifted (eye movement is slower than the other but eventually gets to where its supposed to go)

Front 2

What does each clinical eye test listed test for?

A. Cover-uncover test
B. Red glass test

Back 2

A. Cover-uncover test is for phorias testing. (If you cover the patient's affected eye for a while then uncover it, you'll notice that while it was covered, the weak eye will have deviated to the side.)
B. Red glass test: used to test for diplopia to discern which eye is the one with double vision.

Front 3

What is the innervation to

A. Edinger West-phal nucleus
B. Lateral rectus muscle
C. Levator palpebrae superioris
D. Superior oblique

Back 3

A. CN III
B. VI
C. III
D. IV

Front 4

What palsy does this describe: In a primary forward gaze, the eye ipsilateral to the lesion is esotropic. If you ask the patient to look to the left, the gaze will be normal because both eyes can gaze that way. But if you ask them to shift their gaze to the right, then the right eye will be unable to do so. Double vision will be present still.

Back 4

Abducens nerve palsy of the R eye.

Front 5

What palsy does this describe: Slightly hypertrophic and extorsion- exhibiting eye. Pt. will experience double vision plus one image will be slightly turned in comparison to the other. They will try to put their whole visual field in the upper quadrant.

Back 5

Trochlear nerve palsy.

Coloquially, head tilt and chin tuck is what the patient will be doing.

Front 6

What palsy does this describe: Patient experiences ptosis and dilated pupil on affected side. Eye will look down and out.

Back 6

Oculomotor nerve palsy!

Most severe of the CN palsies.

Front 7

_______ is the act of directing the fovea to new objects of interest; ______ are ballistic eye movements.

Back 7

Foveation ; saccades

Front 8

Regarding types of eye movements and their functions, which involves "slow tracking movements that allow us to remain foveated on a a moving object".

A. optokinetic eye movements that stabilize gaze
B. optokinetic eye movements that shift gaze
C. smooth pursuit that stabilizes gaze
D. smooth pursuit that shifts gaze
E. vestibulo-ocular movement that stabilizes gaze
F. vestibulo-ocular movement that shifts gaze

Back 8

D. smooth pursuit that shifts gaze

Front 9

Regarding types of eye movements and their functions, which involves " involuntary movement of eyes in response to displacement of head".

A. optokinetic eye movements that stabilize gaze
B. optokinetic eye movements that shift gaze
C. smooth pursuit that stabilizes gaze
D. smooth pursuit that shifts gaze
E. vestibulo-ocular movement that stabilizes gaze
F. vestibulo-ocular movement that shifts gaze

Back 9

E. vestibulo-ocular movement that stabilizes gaze

Front 10

Regarding types of eye movements, which is for shifting gaze and which is for stabilizing gaze?

Back 10

Shifting gaze movements are: saccades, smooth pursuit, vergence.

Stabilizing gaze movements are: vestibulo-ocular movement, optokinetic eye movement

Front 11

Regarding types of eye movements and their functions, which involves "movements of the eyes that compensate for head movements and that are stimulated by large scale movement of the visual field".

A. optokinetic eye movements that stabilize gaze
B. optokinetic eye movements that shift gaze
C. smooth pursuit that stabilizes gaze
D. smooth pursuit that shifts gaze
E. vestibulo-ocular movement that stabilizes gaze
F. vestibulo-ocular movement that shifts gaze

Back 11

A. optokinetic eye movements that stabilize gaze

Front 12

This eye movement is important for foveating eyes on objects that are at different distances. Ex. If looking at a paper in front of you then looking to focus on the projected lecture images, your eyes go through this process. These are the only normally disconjugate eye movements in a nonpathalogical manner.

Back 12

Vergence (converging or diverging) , a type of shift gaze

Front 13

True or False:

Saccades can be adjusted on the fly as you go from the start to target.

Back 13

FALSE. Called ballistic, because let’s say as you are adjusting from that object’s first move, it moves again quickly, you will miss it. You cannot adjust on the fly. If a saccade starts, it needs to be finished then a whole new one will start.

Front 14

Regarding neural control of saccadic eye movements, the main projection is a corticobulbar tract neuron and it will send an axon contralaterally to the pontine or midbrain nuclei, depending on whether the saccade is shifting your gaze horizontally (then to [ midbrain / pontine ] ) or vertically (then to [ midbrain / pontine ] ).

Back 14

horizontally is pontine (paramedian pontine reticular formation) ; vertically is midbrain (rostral midbrain reticular formation)

Front 15

Detail the neural circuit for horizontal gaze.

Back 15

Hint 15

Projections from FEF decussate and go to the contralateral PPRF. PPRF sends ipsilateral axons to the abducens nucleus which sends axons to ipsilateral LR muscle and contra laterally to ocular motor nucleus, specifically the motor neurons controling medial rectus, sends axons ipsilaterally.

Front 16

What do you get with each lesion (except 5)?

Back 16

Hint 16

Lesion 1: R abducens nerve affected so we will have a defect in the right lateral gaze.
Lesion 2: R abducens nucleus . Not able to contract lateral rectus ipsilaterally AND not able to contract the medial rectus muscle contralaterally.
Lesion 3: R PPRF leads to same thing as Lesion 2 since Lesion 3 is affecting the neuron that projects to the area of Lesion 2.

Lesion 4: Left MLF (medial longitudinal fasiculus – the axon whose cell body is in the R abducens nucleus, axons going to the oculomotor nucleus) lesion. You are able to look to the left with both eyes but if you look to the R side, the R eye is able to laterally deviate but the L eye is not able to medially deviate. Because this is a disconjugate movement, there is a component of nystagmus associated with this lesion.

Not shown here but note that if you lesion the frontal eye fields, your eyes will be deviated toward the side of the lesion (both of em) they’d be locked in an ipsilateral gaze of the lesion and would be unable to gaze away from that side. (see next slide)

Front 17

Regarding neural control of saccadic eye movements, what happens with lesion of left corticospinal tract pathway and frontal eye fields (FEF)?

Back 17

"right-way eyes" , a contralateral conjugate gaze paralysis where eyes are paralyzed towards the side of the lesion and the contralateral body side to the lesion is paralyzed.

Front 18

True or False:

"Wrong-way eyes" always indicate a lesion of the frontal eye fields (FEF).

Back 18

FALSE. Only right-way eyes do! Wront way eyes, when eyes are paralyzed AWAY from the side of the lesion, is caused by a variety of problems and doesn't necessarily indicate a lesion of the FEFs. Causes include seizure activity in lesioned cortex, thalamic hemorrhage, pontine lesions (affecting corticospinal tract and abducens nucleus).

Front 19

What is "locked-in" syndrome and a lesion through where is the common cause?

Back 19

Locked-in syndrome : lose almost all voluntary control of muscles. Diving Bell and the Butterfly is the story written by a man with that syndrome.

This syndrome usually occurs due to a large leison through the pons. With such a lesion you are lesioning the horizontal gaze center, corticospinal tract. One of the few systems conserved are those that start in the midbrain. Thus, leaving vertical upward gaze.

Front 20

Lesions of dorsal midbrain and pretectum (from pineal tumors or hydrocephalus) produce ___________. What are the symptoms?

A. Locked-In syndrome
B. Parinaud syndrome
C. Right-way gaze syndrome

Back 20

B. Parinaud syndrome

* MAIN 2 symptoms : Impairment of upward gaze
Setting sun syndrome (conjugate downward gaze)

Other side symptoms: Large, unreactive pupils
Eyelid abnormalities
Impaired convergance

Front 21

True or False:

Smooth pursuit involves an initial saccade.

Back 21

True. Smooth pursuit – once that thing starts moving, there is a quick catch-up saccade. Then the smooth pursuit occurs.

An important player too in smooth pursuit is the cerebellum because it has input to tell the extraocular nuclei how fast to move to keep match to the velocity of the object.

Front 22

Detail the neural control of smooth pursuit circuit.

Back 22

Front 23

Detail the neural control of vergence.

Back 23

Front 24

What eye movement circuitry pathway is this?

Back 24

Neural control of vergance

Front 25

What eye movement circuitry pathway is this?

Back 25

Neural circuitry of smooth pursuit

Front 26

What eye movement circuitry pathway is this?

Back 26

Neural control of horizontal saccades