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46 Cards in this Set

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Occulomotor nucleus situated in rostral midbrain
CN III
CN III innervates
Levator palpebrae
Superior rectus
Medial rectus
Inferior rectus
Inferior oblique
This occulomotor nucleus is situated in caudal midbrain, axons decussate before exiting DORSAL aspect of midbrain
Trochlear
CN IV innervates _
Superior oblique on the opposite side
This occulomotor nucleus is located in caudal pons
Abducens
CN VI innervates _
Lateral rectus muscle
Area of the retina with highest visual acuity
FOVEA
TRACKING MOVEMENTS - involuntary (follow my finger ) are called _
SMOOTH PURSUIT
These movements direct eyes from one target to another - voluntary - called _
SACCADES
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 _
VESTIBILO- OCCULAR REFLEx
Normal head movements activate VOR and eyes go _
OPPOSITE the rotation
This is a fixation reflex - if object is moving across the field - saccades to spot it and then smooth pursuit to track it
OPTOKINETIC REFLEX
Lesions to labyrinth, CN VIII, cerebellum or brainstem result in _
SPONTANEOUS NYSTAGMUS
Lesion to _ produces imbalance in vestibular stimulation - brain sees it as normal stimulation from rotation or gravitational forces
LABYRINTH
If right labyrinth is damaged-->you get more activity in the _ --> brain sees head turning to _ --> so nystagmus is to _ and falling to _
LEFT

LEFT

LEFT

RIGHT
With acoustic neuroma what kind of hearing deficit is there
Deafness in same ear
If you have bilateral destruction of vestibular hair cells would you be able to see clear
CLEAR VISION IS NOT POSSIBLE - there is no VOR
If you have brainstem lesion is nystagmus permanent or transitory
PERMANENT - no nuclei to compensate
Site of sensory integration - directs head and eyes toward stimulus
SUPERIOR COLLICULUS
Superficial layer of superior colliculus gets input from _ and projects to _
Retina and visual cortex

Pulvinar --> cortex --> superior colliculus
Deep layer of superior colliculus gets input from _ and projects to _ and functions to _
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
Lateral vestibular nucleus is associated with _
Antigravity muscles
Medial vestibular nucleus is associated with _
Extraocular nuclei via MLF, tectum and gaze centers
A bundle of axons that course through brainstem, includes axons that interconnect nuclei of occular motion
MEDIAL LONGITUDINAL FASCICULUS
Consists of paramedian pontine RF and interneurons in abducens nucleus
HORIZONTAL GAZE CENTER
Horizontal gaze center requires that _ are working in concert - they are connected by _
Abducens and occulomotor nuclei

MLF
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 _
Nucleus prepositus hypoglossi

Medial vestibular nucleus and flocculus of cerebellum
Consists of rostral intersitual nucleus of MLF, gets input from paramedian pontine RF and vestibular nuclei - projects to occulmotor nucleus
VERTICAL GAZE CENTER
Integrator of vertical gaze center (source of stop-drift signal) is _
Interstitial nucleus of Cajal
Pressure on the midbrain or lesion will affect _ gaze - _ gaza will be intact
VERTICAL

HORIZONTAL
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 _
Left eye abducts

Right eye doesnt aDDuct

Convergence is intact - both occulomotor nuclei are intact

Internuclear ophtalmoplegia
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
Contralateral (left) abducens nucleus is intact

NOTHING

Only left eye abducts

One and a half syndrome
Intranuclear ophthalmoplegia and one and a half syndrome are often caused by _
MULTIPLE SCLEROSIS or PONTINE STROKE
- Caused by lesions above brainstem
- Interrupts voluntary saccades
- Reflexive eye movements are intact, VOR is intact
SUPRANUCLEAR OPHTHALMOPLEGIA
Will involve rostral interstitual nucleus of MLF and interrupts vertical saccades - CAUSED BY PINEAL TUMOR
Lesion at Posterior commisure
Frontal eye fields project to _
Paramedian pontine reticular formation
Rostral interstitual nucleus of MLF
Superior colliculus
Inhibits fixation and directs voluntary saccades to contralateral side
Frontal eye fields
Lesions of this result in "enhanced fixation" and inability to direct saccades to contralateral side
Frontal eye fields
Prevents unwanted saccades (prevents from looking at every single object) - commonly lesioned in Huntingtons - innumerable saccades at every distracting object in environment
Prefrontal cortex
- Directs attention toward visual object
- Projects to Frontal Eye Fields - stops fixation and allow saccade to new object
Posterior parietal cortex
Lesion of frontal eye field or posterior parietal cortex disrupt _
VOR
Neurons from pretectal area are bilaterally innervated by _
Edinger-Westphal nucleus
These neurons are are preganglionic parasympathetic and innervated ciliary ganglion
Edinger-Westphal nucleus
Fibers from ciliary ganglion innervate _
Constrictor pupillae muscles
Accomodation reflex REQUIRES _
Intact occipital cortex and patient must cooperate
Accomodation reflex comes into play when you view something at close distance (reading a book) and involves three actions _
- 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