Neuro Eye Movements Ssom Forster 4/27/10

Front 1

Pupillary reflexes

Back 1

light reflex
accommodation reflex
blink (corneal) reflex

Front 2

Light reflex
(induced by, what happens to each eye)

Back 2

induced by bright light shown into pupil of one eye
constriction of the pupil (direct or ipsi response)
small constriction of other pupil (consenual or contra response)

Front 3

Parasympathetic control of pupil constriction
(whole pathway)

Back 3

Front 4

Constriction
PSNS or SNS?

Back 4

PSNS

Front 5

Lesions of Ed-West nucleus or
oculomotor nerve

Back 5

mydriasis (abnormal dilation ipsi to lesion)
impaired direct constriction of ipsi pupil (when light shined in) but intact consensual constriction of contra pupil
impaired consensual response of affected pupil (when light directed at unaffected pupil)

Front 6

Dilation
PSNS or SNS?

Back 6

SNS

Front 7

Sympathetic control of dilation

Back 7

Front 8

Lesions involving SNS control of pupil dilation result in _
and _

Back 8

ipsi miosis (abnormal constriction of pupil on side of lesion)
impaired dilation of ipsi pupil

Front 9

Coordinated eye movements
(name)

Back 9

saccades (vol or invol)
smooth pursuits (invol/reflexive)
vestibulo-ocular movements (invol/reflex)
optokinetic movements (invol/reflex)

Front 10

Role of invol eye movements
(3)

Back 10

compensate for disturbances to visual field (ex. moving head), allowing eyes to remain fixed on object of interest

compensate for adaptation by retina, so that the perception of objects does not actually disappear as a result of adaptation by photoreceptors

scanning the features of an object, critical for object recognition

Front 11

intorsion

Back 11

movement of upper pole of eye inwards

Front 12

extorsion

Back 12

movement of upper pole of eye outwards

Front 13

convergence

Back 13

both eye adduct
medial rectus

Front 14

divergence

Back 14

both eyes abduct
lateral rectus

Front 15

Motor Neuron Innervation of Extraocular Eye Muscles

Back 15

Front 16

Saccades
(what, function)

Back 16

rapid, ballistic movement that change point of fixation

function to direct eyes to object of interest
only type of coordinated eye movement that can be performed easily voluntary

Front 17

Saccades
(two brainstem regions)

Back 17

horiz gaze center:
paramedian pontine reticular formation (PPRF)

vert gaze center:
upper (rostral) midbrain reticular formation

Most saccade movements are combo of horiz and vert

Front 18

Pathway Involved in Generation of Horizontal Gaze/Saccade

Back 18

Front 19

Horizontal Saccades:
neurons of _ project to _
these innervate _ via _
and also innervate _ via _
neurons of the oculomotor nucleus innervate _ via _

Back 19

PPRF to ipsi abducens nucleus in pons

abducens nucleus to ipsi LR via CNVI

abducens nucleus to contra oculomotor nucleus via MLF

oculomotor nucleus to ipsi medial rectus via CNIII

Front 20

Saccade to right side of binocular field (both eyes right)
activation of _ PPRF to _____

Back 20

right PPRF to:
right abducens nucleus and nerve,
causing contraction of LR of right eye,
moving right eye to right (abduction)

activate right abducens neurons,
which activate left oculomotor nucleus and nerve,
causing contraction of medial rectus of left eye,
moving left eye to right (adduction)

Front 21

Gaze Deficits
dysconjugate gaze

Back 21

eyes in different position
lesions of neural circuitry underlying saccades/gaze
causing diplopia

Front 22

Deficits in Horizontal Eye Movements

Back 22

Front 23

Lesions of abducens nerve (1)

Back 23

impaired abduction ipsi eye (*abducens palsy*) causing
*horizontal diplopia*,
but at rest gaze medial (*medial strabismus*)

Front 24

Deficits in Horizon Gaze
(due to _ _ _ _)

Back 24

stroke
diabetes
head trauma
myelin degen

Front 25

Lesions of abducens nucleus
(Lesion 2)

Back 25

impaired abduction in ipsi eye and
impaired adduction in contra eye
so gaze towards the side of lesion impaired called
*lateral gaze palsy*
gaze preference at rest away from lesion

Front 26

Lesion of PPRF
(Lesion 3)

Back 26

impaired abduction in ipsi eye and
impaired adduction in contra eye
so gaze towards the side of lesion impaired called
*lateral gaze palsy*
gaze preference at rest away from lesion

Front 27

Lesion of MLF
(lesion 4)

Back 27

internuclear ophthalmoplegia (INO)
impaired adduction of ipsi eye
nystagmus in contra eye

Front 28

Large lesions that encompass:
MLF, abducens nucleus, and/or PPRF
(lesion 5)

Back 28

ipsi INO
lateral gaze palsy, so
ipsi eye can not abduct or adduct
contra eye eye can't adduct,
termed *one-and-a-half syndrome*

Front 29

nystagmus

Back 29

rhythmic form of eye movement comprised of slow movements in one direction and rapid movements in other direction

Front 30

bilateral lesions of the PPRF or abducens nucleus

Back 30

gaze paralysis
(total loss of horizontal gaze)

Front 31

lesions of oculomotor nerve

Back 31

impaired adduction ipsi during gaze (oculomotor palsy)
at rest: lateral strabismus

down and out
diagonal diplopia
pupil on side of lesion unresponsive to light
mydriasis

Front 32

oculomotor dysfunction useful diagnostic tool for _ aneurysm

Back 32

posterior communicating artery

Front 33

trochlear nucleus lesions

Back 33

contra trochlear palsy:
extorsion of eye
vertical diplopia when eye looks nasally and looks down

Front 34

trochlear nerve lesions

Back 34

ipsi trochlear palsy:
extorsion of eye
vertical diplopia when eye looks nasally and looks down

Front 35

Higher control of Gaze and Saccades
PPRF receives input from _

Back 35

contra superior colliculus

Front 36

Higher control of Gaze and Saccades
Superior Colliculus

Back 36

PPRF receives input from Sup Colliculus
sup colliculus receives direct visual input from optic tract to facilitate reflexive saccades in direction of visual stimuli
SC receives auditory and somatosen input,
which facilitates reflexive saccades in the direction of touch or noise

Front 37

lesions of superior colliculus

Back 37

deficits in involuntary saccades

Front 38

for voluntary saccades, PPRF receives input from

Back 38

contra FEF

Front 39

lesions of FEF

Back 39

deficits in voluntary gaze

Front 40

Lesions to FEF

Back 40

deficits in voluntary gaze contra to lesion
at rest: towards side of lesion

Front 41

Right way eyes

Back 41

gaze at rest *away* from side of weakness
lesion must be oppo side of brain to weakness
thus eye gaze toward side of lesion indicating
*frontal cortex* lesion

Front 42

Wrong way eyes

Back 42

gaze preference towards (ipsi) the side of weakness
lesion oppo side of body to weakness
eye gaze contra to lesion
lesion of pons (PPRF or abducens nucleus)

Front 43

Vestibulo-ocular reflexes (VOR)

Back 43

compensate for disturbances to visual field during head and body movements, allow eyes to remain fixed on object of interest:
head rotation causes eye movement in oppo direction

Projections from *vestibular nuclei* innervate contra abducens nucleus via MLF

Front 44

Pathways controlling VOR

Back 44

if head moves horiz to left, left vestibular nuclei activated which:
activate right abducens nucleus to cause abduction of right eye (right eye to right)
activate left oculomotor nucleus to cause adduction of left eye (left eye moves right)

Front 45

Lesion in MLF in pons

Back 45

bilateral VOR deficits directed towards side of lesion
(the lesion would be on the opposite side to the direction of head turn that elicited VOR deficit)
right lesion results in loss of right horiz VOR when patient moves head to left

Front 46

Lesion of MLF in midbrain

Back 46

loss of horiz VOR in eye ipsi to lesion in the direction away from the lesion
(the lesion would be on same side as the direction of head turn that elicited the VOR deficit)
left lesion will result in loss of right horiz VOR in left eye when the patient moves their head to the left b/c left eye no longer adducts