Neuroanatomy - Ccculomotor Control

Front 1

Occulomotor nucleus situated in rostral midbrain

Back 1

CN III

Front 2

CN III innervates

Back 2

Levator palpebrae
Superior rectus
Medial rectus
Inferior rectus
Inferior oblique

Front 3

This occulomotor nucleus is situated in caudal midbrain, axons decussate before exiting DORSAL aspect of midbrain

Back 3

Trochlear

Front 4

CN IV innervates _

Back 4

Superior oblique on the opposite side

Front 5

This occulomotor nucleus is located in caudal pons

Back 5

Abducens

Front 6

CN VI innervates _

Back 6

Lateral rectus muscle

Front 7

Area of the retina with highest visual acuity

Back 7

FOVEA

Front 8

TRACKING MOVEMENTS - involuntary (follow my finger ) are called _

Back 8

SMOOTH PURSUIT

Front 9

These movements direct eyes from one target to another - voluntary - called _

Back 9

SACCADES

Front 10

Find an object of interest and focus on it - while focused turn head to the right - even though your head moved you were able to keep eyes focused - this is _

Back 10

VESTIBILO- OCCULAR REFLEx

Front 11

Normal head movements activate VOR and eyes go _

Back 11

OPPOSITE the rotation

Front 12

This is a fixation reflex - if object is moving across the field - saccades to spot it and then smooth pursuit to track it

Back 12

OPTOKINETIC REFLEX

Front 13

Lesions to labyrinth, CN VIII, cerebellum or brainstem result in _

Back 13

SPONTANEOUS NYSTAGMUS

Front 14

Lesion to _ produces imbalance in vestibular stimulation - brain sees it as normal stimulation from rotation or gravitational forces

Back 14

LABYRINTH

Front 15

If right labyrinth is damaged-->you get more activity in the _ --> brain sees head turning to _ --> so nystagmus is to _ and falling to _

Back 15

LEFT

LEFT

LEFT

RIGHT

Front 16

With acoustic neuroma what kind of hearing deficit is there

Back 16

Deafness in same ear

Front 17

If you have bilateral destruction of vestibular hair cells would you be able to see clear

Back 17

CLEAR VISION IS NOT POSSIBLE - there is no VOR

Front 18

If you have brainstem lesion is nystagmus permanent or transitory

Back 18

PERMANENT - no nuclei to compensate

Front 19

Site of sensory integration - directs head and eyes toward stimulus

Back 19

SUPERIOR COLLICULUS

Front 20

Superficial layer of superior colliculus gets input from _ and projects to _

Back 20

Retina and visual cortex

Pulvinar --> cortex --> superior colliculus

Front 21

Deep layer of superior colliculus gets input from _ and projects to _ and functions to _

Back 21

Dorsal column and spinal trigeminal, inferior colliculus, frontal eye fields

Spinal cord within medial vestibulospinal tract and RF (paramedian pontine RF)

Direct eyes to visual and auditory stimuli

Front 22

Lateral vestibular nucleus is associated with _

Back 22

Antigravity muscles

Front 23

Medial vestibular nucleus is associated with _

Back 23

Extraocular nuclei via MLF, tectum and gaze centers

Front 24

A bundle of axons that course through brainstem, includes axons that interconnect nuclei of occular motion

Back 24

MEDIAL LONGITUDINAL FASCICULUS

Front 25

Consists of paramedian pontine RF and interneurons in abducens nucleus

Back 25

HORIZONTAL GAZE CENTER

Front 26

Horizontal gaze center requires that _ are working in concert - they are connected by _

Back 26

Abducens and occulomotor nuclei

MLF

Front 27

Saccades must be followed by hold signal if the eye is to remain in place (otherwise the eye drifts to midline) from _ . This requires an integrator signal - in this instance it comes from _

Back 27

Nucleus prepositus hypoglossi

Medial vestibular nucleus and flocculus of cerebellum

Front 28

Consists of rostral intersitual nucleus of MLF, gets input from paramedian pontine RF and vestibular nuclei - projects to occulmotor nucleus

Back 28

VERTICAL GAZE CENTER

Front 29

Integrator of vertical gaze center (source of stop-drift signal) is _

Back 29

Interstitial nucleus of Cajal

Front 30

Pressure on the midbrain or lesion will affect _ gaze - _ gaza will be intact

Back 30

VERTICAL

HORIZONTAL

Front 31

Patient has internuclear lesion of MLF on the RIGHT - you ask patient to look left - which eye abducts and which doesnt adduct

Is convergence intact

This lesion is called _

Back 31

Left eye abducts

Right eye doesnt aDDuct

Convergence is intact - both occulomotor nuclei are intact

Internuclear ophtalmoplegia

Front 32

Lesion of MLF and ipsilateral abducesn nucleus - on the RIGHT

Which abducens is intact

What happens when you ask patient to look to right

Ask to look left?

What is this condition called

Back 32

Contralateral (left) abducens nucleus is intact

NOTHING

Only left eye abducts

One and a half syndrome

Front 33

Intranuclear ophthalmoplegia and one and a half syndrome are often caused by _

Back 33

MULTIPLE SCLEROSIS or PONTINE STROKE

Front 34

- Caused by lesions above brainstem
- Interrupts voluntary saccades
- Reflexive eye movements are intact, VOR is intact

Back 34

SUPRANUCLEAR OPHTHALMOPLEGIA

Front 35

Will involve rostral interstitual nucleus of MLF and interrupts vertical saccades - CAUSED BY PINEAL TUMOR

Back 35

Lesion at Posterior commisure

Front 36

Frontal eye fields project to _

Back 36

Paramedian pontine reticular formation
Rostral interstitual nucleus of MLF
Superior colliculus

Front 37

Inhibits fixation and directs voluntary saccades to contralateral side

Back 37

Frontal eye fields

Front 38

Lesions of this result in "enhanced fixation" and inability to direct saccades to contralateral side

Back 38

Frontal eye fields

Front 39

Prevents unwanted saccades (prevents from looking at every single object) - commonly lesioned in Huntingtons - innumerable saccades at every distracting object in environment

Back 39

Prefrontal cortex

Front 40

- Directs attention toward visual object
- Projects to Frontal Eye Fields - stops fixation and allow saccade to new object

Back 40

Posterior parietal cortex

Front 41

Lesion of frontal eye field or posterior parietal cortex disrupt _

Back 41

VOR

Front 42

Neurons from pretectal area are bilaterally innervated by _

Back 42

Edinger-Westphal nucleus

Front 43

These neurons are are preganglionic parasympathetic and innervated ciliary ganglion

Back 43

Edinger-Westphal nucleus

Front 44

Fibers from ciliary ganglion innervate _

Back 44

Constrictor pupillae muscles

Front 45

Accomodation reflex REQUIRES _

Back 45

Intact occipital cortex and patient must cooperate

Front 46

Accomodation reflex comes into play when you view something at close distance (reading a book) and involves three actions _

Back 46

- Accomodation of the lens (contraction of the ciliary muscle - relax the lens)
- Convergence - bilateral contraction of MR muscles
- Pupillary constriction - EW --> ciliary ganglion --> sphincter pupillae