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439 Cards in this Set

  • Front
  • Back
Fx of semicircular canals?
detect ANGULAR acceleration or deceleration in three planes: horizontal, vertical, and lateral simultaneously
Roll is?
rotation around the x axis
Pitch is?
rotation around the Y axis
YAW is?
rotation around the z axis
YAW stimulates which semicircular canal?
What 2 positions place the lateral canals in a vertical position?
1)extending the head backward 60 degrees; 2)lifting head up by 30 degrees w/ a pillow
Flexing the head 30 degress forward puts the lateral canal in what position?
horizontal position
In what direction does the endolymph move in response to the head movement?
head moves one way and endolymph moves other way
In the horizontal ampulla, what direction are the cilia orientated in response to the utricle?
toward the utricle
In the ampulla that aren't horizontal, that direction are the cilia orientated in response to the utricle?
away from the utricle
How are semicircular canals arranged on either side of the head?
they are functionally paired on either side of the head because they lie in common planes - like a "hula hoop"
Head movement to the L stimulates?
afferent firing from L horizontal canal and inhibits firing from R
Does head movement to L have an effect on the posterior and anterior canals?
NO because they are not in plane of rotation
Right anterior canal paired w/?
left posterior canal
Right posterior canal paired w/?
left anterior canal
Sensory incoming for VOR is?
Motor outgoing for VOR is?
CN 8
CN 3,4,6
Does VOR have short latency or long?
short latency due to change in APs in the ampulla; 12 milliseconds
Is VOR the fastest reflex?
NO; knee-jerk reflex is the fastest because it has only one synapse
When head moves R what happens to endolymph and kinocilium?
endolymph lags behind causing fluid to flow to L; kinocilium on R is stimulated and on L is inhibited
Clinical tests of the vestibular system check?
Pons, CN 3, 4, 6
Warm water induces nystagmus that beats towards?
warm ear
Cold water induces nystagmus that beats away from?
cold ear
APs decrease or increase in ear with cold water?
How long does caloric nystagmus last?
as long as there is a temperature gradient
Rotational testing w/ Barany chair causes nystagmus in what direction? How long does nystagmus last?
in direction of the chair rotation; 30 seconds
Optokinetic nystagmus occurs when? How long does it last?
lights are on and pt can see environment as chair is being turned; lasts as long as the chair is turning because eyes are tracking visual clues
CN needed for optokinetic nystagmus?
CN2 is sensory in and CN3,6 is motor out
Sudden full stop of the rotating Barany chair will cause? In what direction?
postrotary nystagmus in the direction opposite of chair movement
What causes postrotary nystagmus?
sudden stop of head and semicircular canals, but endolymph keeps on moving in direction chair was turning
What is the most common vestibular disorder?
benign positional vertigo
Benign positional vertigo; symptoms?
otoconia displaced from utricle macula becomes lodged in cupula of the posterior canal; brief episodes of vertigo that coincide w/ changes in body position
Labyrinthine disease also known as?
seasickness and space sickness
Subjective symptoms of labyrinthine disease?
vertigo, nausea, oscillopsia, anxiety
Objective symptoms of labyrinthine disease?
nystagmus, falling or postural deviation, sweating, pallor, vomiting, hypotension
Acute peripheral vestibulopathy
spontaneous attack of vertigo of unapparent cause; usually due to infection
Acute peripheral vestibulopathy includes what 2 diseases?
acute labyrinthitis, vestibular neuronitis
Acute peripheral vestibulopathy characterized by?
vertigo, nausea, and vomiting of acute onset; can last up to 2 wks
What are two types of drugs that damage the vestibular system?
aminoglycosides, Gentamyacin
What CN helps w/ pupillary reflex by controlling sphincter muscles and ciliary muscles?
What CN keeps eyelid up?
CN3 controls which eye muscles?
superior rectus, medial rectus, inferior rectus, inferior oblique
What CN controls lateral rectus?
What CN controls superior oblique?
What happens when you contract the superior oblique muscle?
eyes moves in (intorsion) and downward
What happens when you contract inferior oblique?
eye moves outward (extorsion)
Supranuclear regulation of eye movements found in?
brainstem, cerebellum, and forebrain including the basal ganglia
Forebrain contains which eye fields?
frontal eye fields
Horizontal eye movement control center?
What nucleus is the horizontal gaze center and what does it control?
abducens nucleus; controls ipsilateral lateral rectus and contralateral medial rectus
What is the interconnection between the occulomotor, trochlear, abducens, and vestibular nuclei?
MLF medial longitudinal fasiculus
What does the paramedian pontine reticular formation do?
PPRF provides output to the abducens from higher cortical eye movement control centers
Lesion of the PPRF or abducens nucleus will cause?
ipsilateral horizontal gaze palsy; problem w/ moving both eyes in directed gaze
What CN closes the eyelid?
What has cell bodies for CN3?
Tegmentum contains?
CN3 cell bodies; reticular formation
Corneal reflex controlled by?
CN5, CN7
"Blink to threat" is which CNs?
CN2, CN7
Vertical and vergence eye movement control center is?
Where are vertical eye movements initiated?
rostral midbrain reticular formation and pretectal area
Rostral midbrain reticular area controls?
superior and inferior rectus muscles and the inferior and superior oblique muscles
Dorsal region of rostral midbrain reticular area controls?
upward gaze
Ventral region of rostral midbrain reticular area controls?
downward gaze
Midbrain reticular formation initiates?
vergence eye movements
What muscles cause convergence of the eyes?
medial rectus muscles
What muscles cause divergence of the eyes?
lateral rectus muscles
What controls eye movement for near and far vision?
descending control from occipital and parietal cortex
Forebrain centers controlling eye movements send information from cerebral cortex to?
brainstem centers and the superior colliculi
Frontal eye fields stimulate?
contralateral PPRF; generate conjugate eye movements to the contralateral side
Lesion of the frontal eye field causes?
BOTH eyes to gaze toward lesioned side; eyes look away from paralysis
Parieto-occipito-temporal cortex stimulates?
smooth pursuit eye movements in the ipsilateral direction
If you stimulate the L frontal eye fields in which direction is the conjugate eye movement?
What are the two principal types of eye movements?
eye movements that change the line of sight (usually voluntary); eye movements that keep the retinal image steady (reflex)
Do eye muscles pull against gravity?
No; they also always have the same mechanical load
What is the pulse of innervation?
phasic increase or burst of neural activity in the occular motor nuclei that is needed to generate a powerful contraction of the extraocular muscles to overcome the viscous resistance associated w/ eye movement
Amplitude or velocity of eye movement correlated w/?
duration of the burst or pulse of APs
What is the fastest of the eye movements?
What eye movement is ballistic?
saccadic; can't change course of eye movement in response to subsequent changes in the target during the delay period
What is the delay time between the appearance of the target of interest and the onset of eye movement?
200 msec
Smooth pursuit system generates?
smooth following movements of the eyes that closely match the pace of the target; keep targets on the fovea
Humans can't generate smooth pursuit eye movements w/o?
a target
What type of lesion leads to ataxic eye movements?
cerebellum lesions
What do vergence eye movements do?
align the fovea of each eye w/ targets located at different distances from the observer
What is the only type of eye movement that causes eyes to move in opposite directions?
vergence eye movements
Near reflex triad consists of?
convergence of the eyes, accomodation of the lens (PNS), constriction of the pupil (PNS)
Which 2 CNs operate together to hold images stable on the retina?
What system used during brief or rapid head movement?
vestibular system
What system used during sustained or slow head movement?
optokinetic system
What is optokinetic nystagmus composed of?
a pursuit eye movement to track the moving environment and then reset w/ a fast saccade
How long does the optokinetic system maintain its affect?
until the field of vision stops moving
What acts as a back-up to the VOR?
optokinetic system
Lateral axon motor axons terminate?
on lateral groups of ventral horn motor neurons and interneurons
Lateral motor systems control movement of?
extremities - arms, legs, feet, hands
What are the two tracts in the lateral motor system
lateral corticospinal tract and rubrospinal tract
Rubrospinal tract?
Increasese flexor tone in the upper extremities
Both lateral motor tracts provide for?
rapid, dexterous movements at individual joints or digits
Lesion in lateral motor system first leads to? Then to?
weakness; hyperreflexia (spasticity)
If LMNs are gone completely then you get?
How many "AL" inputs are there for the extremities?
single input
LMNs more medial run the?
LMNs more lateral run the?
Why are you not worried about trunk paralysis clinically?
medial motor systems go bilateral to innervate the trunk
Medial motor pathways synapse on?
medial ventral horn motor neurons and interneurons
Medial motor system controls movements of the?
trunk; axial and girdle muscles
Axial and girdle muscles involved in?
postural tone, balance, orientating movements of the head and neck, automatic gait-related movements
Medial motor systems descend?
ipsilaterally and terminate on interneurons; some of whose axons cross the ventral commissure
Medial motor systems influence axial musculature?
What are the 4 tracts in the medial motor system?
anterior(ventral) corticospinal tract, vestibulospinal tract, reticulospinal tract, tectospinal tract
Anterior corticospinal tract controls?
doesn't cross midline; bilateral control of axial and girth muscles
Lateral vestibulospinal tract runs?
length of spinal cord; controls extensor tone
Medial vestibulospinal tract runs?
ends at cervical cord level; controls head and neck muscles
Reticulospinal tract controls?
automatic posture and gait movements
Tectospinal tract controls?
ends in the cervical cord; provides coordination of head and eye movement
Paresis means?
-plegia means?
no movement
Paralysis means?
no movement
Palsy means?
can mean weakness or no movement
Hemi- means?
one side of body
Para- means?
both legs
Mono- means?
one limb
Di- means?
both sides of body equally affected
Quadri- or tetra- means?
all four limbs
Hemisection of spinal cord can cause?
Brown-Sequard syndrome
Brown-Sequard syndrome causes?
ipsilateral UMN signs; ipsilateral loss of vibration, proprioception, joint position, fine touch; contralateral loss of pain, temperature, itch, and crude touch
An anterior spinal artery infarct can damage what pathway?
anterolateral pathways and ventral horn cells
Damage of anterolateral pathway causes?
no pain and temperature sensation below the lesion bilaterally
What water-soluble vitamin is required for myelin formation
vitamin B12 cobalamine
Lack of intrinsic factor causes?
pernicious anemia; also causes tingling and numbness of hands and feet
Paresthesia is?
What fat soluble vitamin is important for neural tissue?
vitamin E
Which has greater degeneration of myelin?
dorsal column degeneration greater than corticospinal tract degeneration
What occurs w/ degeneration of cerebral white matter?
What is infectious myelitis?
inflammation of the spinal cord
Infectious myelitis includes?
HIV, Lyme disease, tertiary syphilis, and poliomyelitis
Inflammatory myelitis includes?
MS, Lupus, postinfectious myelitis
Poliomyelitis affects?
affects "AL"
Amyotrophic lateral sclerosis (ALS) affects?
can affect LMNs and UMNs
Lou Gehrig's Disease is a disease of?
motor neurons
What is Guillain-Barre Syndrome?
acute inflammatory demyelinating polyneuropathy which is an immune mediated demyelination of peripheral nerves
What are the three main brainstem sections?
midbrain, pons, medulla
What is the tectum?
"roof;" composed of the superior and inferior colliculi which lie dorsal to the cerebral aqueduct
What is the tegmentum?
"covering;" lies ventral to the aqueduct (midbrain) and vertral to the 4th ventricle in the pons and medulla
Brain stem tegmentum is the location of?
main bulk of the brain stem nuclei and reticular formation
What is the reticular formation?
groups of neuronal nuclei and meshwork of neuronal axons
What is the basis of the brain stem?
most ventral part of the brain stem (pons and midbrain only)
What is located in the basis?
location of the large collection of fibers and tracts: corticobulbar, corticospinal, corticopontine tracts
What are the three CNs not associated w/ the brain stem?
CN1, CN2, CN11
CN1 and CN2 associated w/?
CN11 associated w/?
cervical spinal cord
What 2 CNs associated w/ the midbrain?
CN3, CN4
What 4 CNs are associated w/ the pons?
CN5, CN6, CN7, CN8
What 3 CNs associated w/ the medulla?
CN9, CN10, CN12
What 3 CNs are sensory?
CN1, CN2, CN8
What sensory CN associated w/ the brain stem?
What are the 5 motor CNs?
CN3, CN4, CN6, CN11, CN12
What motor CNs are associated w/ the brain stem?
CN3, CN4, CN6, CN12
What are the 4 mixed CNs?
CN5, CN7, CN9, CN10
CN9 and CN10 do?
sensory and motor for viscera; parasympathetic NS
CN7 is mainly?
CN5 is mainly?
CN 12 does?
Where are PNS preganglionic neuronal cell bodies for CN3?
Edinger-Westphal nucleus - MIDBRAIN
Where are PNS preganglionic neuronal cell bodies for CN7?
Superior salivatory nucleus -PONS
Where are PNS preganglionic neuronal cell bodies for CN9?
Inferior salivatory nucleus -
Where are PNS preganglionic neuronal cell bodies for CN10?
Dorsal motor nucleus of CN10 - MEDULLA
The postganglionic neurons of CNs 3,7,9,10 innervate?
glands, smooth muscle, and cardiac about the splenic flexure (NOT striated muscle)
What CNs provide the predominant autonomic tone to the head and thoracoabdominal viscera?
CNs 3,7,9,10
Postganglionic parasympathetic neuron cell bodies are found inside or outside the CNS?
Where are the postganglionic parasympathetic neurons located for CN3?
ciliary ganglion
Where are the postganglionic parasympathetic neurons located for CN7?
Sphenopalatine ganglion and submandibular ganglion
Ciliary ganglion axons project to?
eye ciliary muscle and constrictor muscle of the iris
Sphenopalatine ganglion axons project to?
lacrimal glands and nasal mucosa
Submandibular ganglion axons project to?
submandibular and submaxillary salivary glands
Where are the postganglionic parasympathetic neuron cell bodies located for CN9?
otic ganglion
Otic ganglion axons project to?
parotid gland
Where are the postganglionic parasympathetic neuron cell bodies located for CN10?
various terminal ganglion
Axons for various terminal ganglion project to?
effector organs
Sympathetic nervous system innervates?
eyes, face, scalp
Does the descending tract of the SNS from the hypothalamus cross the midline?
Where are all of the SNS preganglionic cell bodies located?
IML of spinal cord; rexed lamina 7; T1-L3
SNS preganglionic cell bodies innervating the head are found?
in the IML of T1-T2
Where are the SNS postganglionic cell bodies located?
superior cervical ganglion
A lesion of the sympathetic pathway to the head will cause?
ipsilateral Horner's Syndrome
What are the three classic signs of Horner's Syndrome?
Miosis, ptosis, anhidrosis
Miosis is?
decreased pupil size
Anhidrosis is?
lack of sweating on the face and neck
Does UMN lesion cause weakness?
Does LMN lesion cause weakness?
Does LMN lesion cause atrophy?
Does UMN lesion cause atrophy?
Does UMN lesion cause fasiculations?
Does LMN lesion cause fasiculations?
What happens to reflexes w/ UMN lesion?
What happens to reflexes w/ LMN lesion?
What happens to tone w/ UMN lesion?
What happens to tone w/ LMN lesion?
What are the 5 main neural tracts coursing through the brain stem?
medial lemniscus, anterolateral system, corticospinal tract, descending hypothalamic SNS fibers, medial longitudinal fasiculus
Medial lemniscus is?
sensory ascending
Anterolateral system is?
sensory ascending for pain, temperature, itch
Corticospinal tract is?
motor descending
Descending hypothalamic SNS fibers are?
motor ANS descending
Brain stem lesions producing ipsilateral Horner's Syndrome may also result in?
contralateral loss of pain and temperature sensations from the limbs and body
MLF goes through?
Pons and Midbrain
What keeps eyeball movements yoked together?
Brain stem lesions of the MLF produce?
internuclear opthalmoplegia (INO) and disrupts the VOR
With INO the eye on the lesioned side can't?
adduct (innervation to the medial rectus lesioned)
What can cause lesions to the MLF?
multiple sclerosis plaques, pontine infarcts, or neoplasms
UMN fibers originate in?
motor cortex
UMN fibers terminate?
motor CN nuclei in the pons and medulla
What innervates all CN nuclei that causes skeletal muscle to contract?
What CNs have alpha motor neurons?
CNs 12,11,7,5
Corticobulbar innervation of the LMN in CNs is?
Each LMN of the brain stem receives input from axons arising from?
both the R and L cerebral motor cortex
What CN is the exception for bilateral innervation?
CN7; facial nerve LMN to the face receives only contralateral UMN innervation
What is Bell's Palsy?
facial nerve lesion (LMN) will cause ipsilateral total (upper and lower) face paralysis
Corticobulbar lesion (UMN) will cause?
only lower face palsy contralateral to the lesion
Cell bodies for CN7 are located?
Does an UMN lesion allow you to wrinkle forehead and close eyelid? Why?
YES; bilateral innervation
Does a LMN lesion allow you to wrinkle forehead and close eyelid? Why?
NO; no bilateral innervation
The nuclei of the CNs are arranged in?
discrete, discontinous, cell columns
Cell bodies with motor fx are found near?
Cell bodies with sensory fx are found near?
lateral border of brain stem
Cell bodies of CNs w/ mixed motor and sensory visceral fx are found near?
sulcus limitans
Rostral solitary nucleus has what input?
taste input
Caudal solitary nucleus has what input?
autonomic sensory input
What can you see in the spinomedullary junction section?
pyramidal tract decussation
What can you see in the caudal medulla section?
dorsal column nuclei - internal arcuate fibers (second order neuron decussation)
What can you see in the rostral medulla section?
inferior olivary nucleus and CN12 nucleus
What can you see in the caudal pons section?
level of genu of CN7
What can you see in the rostral midbrain section?
level of the superior colliculus and CN3
What connects the medulla to the cerebellum?
inferior cerebellar peduncle
What contains the autonomic centers for respiratory, cardiovascular, and GI control?
CN12 is?
motor nerve for the tongue
Nerve fibers for CN12 exit?
between the inferior olive and corticospinal tract
Lesion of LMN for the tongue causes?
tongue to point to the side of the lesioned upon protrusion
Lesion of UMN for the tongue causes?
tongue to point away from the lesioned (affected) side upon protrusion
CN11 is?
motor nerve that moves head to opposite side and rotates and elevates the scapula
Cell bodies for CN11 are located?
in upper 5-6 cervical segments of the spinal cord in the spinal accessory nucleus
Spinal accessory nucleus protrudes?
between the dorsal and ventral horns of the spinal cord
Lesion of CN11 causes?
weakness in turning head to the contralateral side against resistance and ipsilateral shoulder drop
CN10 innervates which skeletal muscles?
pharyngeal and laryngeal muscles (old gill arches)
CN10 motor nucleus is?
nucleus ambiguus
CN10 controls muscles for?
swallowing (gag reflex) and phonation
Other motor innervation for CN10 is?
parasympathetic innervation of smooth muscle and cardiac muscle
What is the nucleus for parasympathetic innervation?
dorsal motor nucleus of CN10
Sensory for CN10 is?
taste from epiglottis and pharynx and aortic arch chemo- and baro- receptors
What is the CN10 nucleus for taste from epiglottis and pharynx?
rostral nucleus solitarius - gustatory
What is the CN10 nucleus for aortic arch chemo- and baro- receptors?
caudal nucleus solitarius - cardiorespiratory
The third sensory function of CN10 is?
somatic sensation from meninges and external ear
Primary sensory neurons for meninges and external ear located in?
superior vagal ganglion
Second order sensory project neuron for meninges and external ear located in?
spinal trigeminal nuclei
Lesion of CN10 causes?
dysphagia, loss of gag reflex, cough, dysarthria w/ hoarseness w/ fixed vocal cord
Bilateral lesion of the vagus is?
fatal w/ complete laryngeal paralysis (rare)
Motor for CN9 is? Nucleus?
stylopharyngeus muscle and parasympathetic innervation of parotid gland; nucleus ambiguus; inferior salivatory nucleus
What is the fx of the stylopharyngeus muscle?
elevates pharynx during talking and swallowing (part of gag reflex w/ vagus)
One sensory function for CN9?Nucleus?
taste from posterior 1/3 of tongue; rostral solitary "gustatory" nucleus w/ vagus
Second sensory function for CN9? Nucleus?
chemo- and baro- receptors in carotid body and carotid sinus; caudal solitarius
"cardiorespiratory" nucleus w/ vagus
Third sensory function of CN9? Nucleus?
general somatic sensation from middle ear, outer ear, pharynx, and posterior 1/3 of tongue; superior glossopharyngeal ganglion for primary neuron; spinal trigeminal nuclei for second order neuron assiciated w/ CN10
Lesion of CN9 causes?
loss of gag reflex w/ CN10
One of the earliest signs of Bell's Palsy is?
outer ear pain
What synapses in VPL?
What synapses in VPM?
What is found in the pyramids?
corticospinal tract; upper motor neuron axons from ipsilateral M1 cerebral cortex
What happens in the pyramidal decussation?
corticospinal tract motor neuron axons cross to the contralateral side of the body
What happens in the anterolateral (ALS) system?
spinothalamic, spinoreticular, and spinomesencephalic tracts, sensory projection neurons encoding pain, itch, and temperature from the contralateral body
What happens in fasiculus and nucleus gracilis?
sensory, primary afferent axons encoding proprioception, fine touch, and vibration BELOW T6 from the ipsilateral body
Axons from below T6 will synapse with?
projection neuron cell bodies in the nucleus gracilis and cross over in the internal arcuate fibers to become the medial lemniscus
What happens in the fasiculus and nucleus cuneatus?
sensory primary afferent axons encoding proprioception, fine touch, and vibration ABOVE T6 from the ipsilateral body
Axons from above T6 will synapse with?
projection neuron cell bodies in the nucleus cuneatus and cross over in the internal arcuate fibers to become the medial lemniscus
What happens in the spinal trigeminal tract and nucleus?
primary sensory axons from ipsilateral face provide pain, temperature, itch, and crude touch sensation for the face, mouth, anterior 2/3 tongue, nasal sinuses, and supratentorial dura as well as encoding pain and temperature for the outer ear on CNs 7, 9, 10
Spinal trigeminal nucleus projection neuron cell bodies send axons which?
cross the midline to travel in the trigeminothalamic tract and synapse in the VPM nucleus of the thalamus
What is the level of the belly button?
What is found in the medial lemniscus?
sensory projection neurons encoding proprioception, fine touch, and vibration from the contralateral body
What happens if internal arcuate fibers are lesioned before they decussate?
ipsilateral damage
What happens if internal arcuate fibers are lesioned after they decussate?
contralateral damage
What is the most common site of stroke in the brain stem?
rostral medulla
What is found in the vestibular nuclei?
sensory neurons from the ipsilateral vestibular membranous labyrinth encoding acceleration (CN8 vestibular portion)
What is found in the solitary nucleus and tract?
sensory fibers from the tongue encoding taste (CN7, 9, 10) with cardio-respiratory information from carotid artery and aortic arch (CN9, 10)
What is found in the hypoglossal nucleus?
LMNs for the ipsilateral half of the tongue (CN12)
What is found in the ambiguus nucleus?
LMNs for muscles in pharynx and larynx (CN9, 10)
What is found in the dorsal motor nucleus of the vagus?
motor preganglionic fibers to viscera in the thorax and abdomen (CN10)
What does the inferior olivary nucleus give rise to?
clmibing fibers that innervate the contralateral half of the cerebellum
What is found in the inferior cerebellar peduncle?
cerebellar afferents including crossed olivocerebellar fibers which become climbing fibers in the cerebellar cortex
What happens if there is a lesion in the descending sympathetic tract from the hypothalamus?
ipsilateral Horner's syndrome and contralateral loss of pain and touch sensation
What CN nuclei are located in the pons?
CN5,6,7,8 nuclei
What is located on the dorsal surface of the pons?
4th ventricle
What connects nuclei in the pons base to the cerebellum?
large thick middle cerebellar peduncles
What 3 fiber tracts are located in the base of the pons?
corticospinal, corticopontine, corticonuclear(bulbar)
The head has bilateral input except for the?
lower face
The ascending auditory pathway is the lateral or medial lemniscus?
What does the lateral lemniscus tract carry?
the bulk of ascending auditory pathways from both cochlear nuclei to the inferior colliculus of the midbrain
Facial nerve fibers curve around?
abducens nucleus
Can pts with Bell's Palsy wrinkle their forehead?
What is "central 7?"
UMN lesion of CN7
What are the symptoms with "central seven?"
weakness in the inferior contralateral face
What CN keeps the eyes yoked together for horizontal eye movements?
What is the center for control of horizontal eye movements?
Innervating the contralateral PPRF causes?
frontal eye fields to generate fast conjugate eye movements to the contralateral side
Lesion of the abducens nerve will cause?
diplopia - CN6 palsy ipsilateral
Lesion of the abducens nucleus will cause?
ipsilateral, lateral gaze palsy
Lesion of the abducens nucleus and ipsilateral MLF will cause?
ipsilateral lateral gaze palsy and internuclear opthalmoplegia
Lesion of the cerebral hemisphere will cause gaze to what side?
side of the lesion
Motor nucleus of CN5 runs from?
upper to mid pons
Sensory nucleus of CN5 runs from?
midbrain to upper cervical spinal cord
What is motor nerve for muscles of mastication?
trigeminal (CN5)
Which trigeminal nucleus does proprioception?
mesencephalic trigeminal nucleus
Which trigeminal nucleus does fine touch and dental pressure?
chief or major trigeminal sensory nucleus
Which trigeminal nucleus does crude touch, pain, and temperature?
spinal trigeminal nucleus
What is found in the abducens nucleus?
LMNs innervating the ipsilateral lateral rectus muscle of the eye
What is important about the internal genu of the facial nerve?
point where the LMNs for the ipsilateral half of the face wrap around the abducens nucleus
What does the facial nucleus contain?
LMNs innervating muscles of the face
What does the vestibular nuclei contain?
sensory neurons from the vestibular portion of the membranous labyrinth encoding acceleration
What does the MLF contain?
motor tract involved with eye movement coordination
What do the axons from the pontine nuclei do?
each one sends an axon across the midline to the middle cerebellar peduncle
What CN nuclei are located in the midbrain?
CN3, 4 nuclei
What does the inferior colliculi process?
auditory information received bilaterally from the cochlear nuclei from the lateral lemniscus
What does the superior colliculi do?
processes and coordinates eye movements
What does the pretectal region contain?
interneurons involved in the pupillary light reflex
What is the largest nucleus in the midbrain?
substantia nigra
Lesion to CN4 will cause?
diplopia and weakness while looking down with abducted eye
Lesion to CN3 will cause?
diagonal diplopia and loss of horizontal gaze
CN3 PNS innervates which 2 intraocular muscles?
Sphincter pupillae muscle and ciliary muscle
Sphincter pupillae muscle does what?
contracts the muscle of the iris and constricts the pupil - MIOSIS
What is mydriasis? What causes it?
pupil dilation; SNS
What does the ciliary muscle do?
contraction causes the lens to increase its curvature
Lesion to the CN3 component will cause?
loss of near vision response and ptosis with dilated pupil and loss of light reflex; eyeball is down and out at rest
What is located in the cerebral peduncles?
descending corticospinal, corticobulbar, and corticopontine fibers from the ipsilateral cortex
What is found in the mesencephalic trigeminal nucleus?
sensory proprioception from muscles of mastication, tongue, and extraocular muscles (CN5)
What is found in the ventral tegmental areas?
dopaminergic neurons projecting to nucleus accumbens and limbic system
What is found in the superior colliculus?
integration of eye movement control
What is found in the periaqueductal gray?
site of origin of descending pain control pathway
What are the red nuclei?
motor nucleus that projects to alpha spinal motor neurons
What is the substantia nigra?
part of the motor control by the basal ganglia
Where do the substantia nigra axons terminate?
in the caudate nucleus and putamen
What is found in the Edinger Westphal nucleus?
PNS preganglionic innervation of the ciliary muscles of the lens and pupillary constrictor muscle
What is found in the medial geniculate nucleus of the thalamus?
auditory pathway to the primary cortex
What is found in the lateral geniculate nucleus of the thalamus?
visual pathway to primary cortex
What is found in the occulomotor nucleus?
innervation of extraocular muscles except for lateral rectus and superior oblique; also keeps the eyelid elevated
Rubrospinal tract causes flexion or extension of upper extremities?
What are the normal conditions of the rubrospinal tract?
normally inhibited by the cortex; otherwise you would have flexion of the UE all the time
What happens if you damage the red nucleus?
you have flexion
What are the three cerebellar arteries?
What blood vessel is located at the pontomedullary jx?
single basilar artery
What blood vessel is located at the pontomesencephalic jx?
paired posterior cerebral arteries
What blood vessel supplies the anterior circulation?
paired posterior communicating arteries
What is the vascular territory for the superior cerebellar artery (SCA)?
arises from top of the basillar artery at level of the rostral pons; supplies superior cerebellum and bit of rostral laterodorsal pons
What is the vascular territory for the anterior inferior cerebellar artery (AICA)?
arises from basilar artery (just after vertebrals fuse) at level of caudal pons; supplies lateral caudal pons and small portion of cerebellum
What is the vascular territory for the posterior inferior cerebellar artery?
arises from vertebral artery at level of medulla; supplies lateral medulla and inferior cerebellum
What is the blood supply to the midbrain?
PCA and penetrating branches "top of the basilar artery"
What is the blood supply to the pons?
basilar artery
What is the blood supply to the medial medulla?
basilar artery
What is the blood supply to the lateral medulla?
vertebral artery and PICA
Infarctions of the brain stem can occur for a number of reasons including?
embolism, thrombosis, and lacunar disease
What is lacunar disease?
small vessel occlusion in the setting of chronic hypertension
If CN3 and CN4 were affected where in the brain stem would the lesion be?
If CNs 5,6,7,8 were affected where in the brain stem would the lesion be?
If CNs 9,10,12 were affected where in the brain stem would the lesion be?
If CN3 was damaged what would you see in your patient?
eye would be down and out, ptosis of eyelid, dilated pupil
If CN7 affected what would you see in pt?
Bell's palsy
If CN8 affected what would you see in pt?
loss of hearing
If CN12 affected what would you see in pt?
problems with the tongue
Lesion to PNS of CN3 causes?
dilated pupil and eyeball that is down and out at rest
If there is an SNS problem of CN3 what do you see in pt?
Horner's syndrome with pinpoint pupil and eyeball looking straight at you
Which trigeminal nucleus is responsible for the jaw-jerk reflex?
mesencephalic trigeminal nucleus
Is cerebral peduncle motor or sensory?
Lesions of the brain stem to any of the long tracts will result in what type of body deficit? What are the long tracts?
contralateral deficit; corticospinal, spinothalamic, medial lemniscus
Lesion to the descending sympathetic hypothalamic fibers ALWAYS results in?
ipsilateral Horner's syndrome on the side of the lesion in the brain stem
Lesion to the cerebellar peduncle will result in?
ipsilateral motor ataxia
Damage to CNs and nuclei will result in?
ipsilateral head sensory and/or motor deficits
Upper midbrain damage signs of dysfunction?
impaired consciousness, flexor posturing, CN3 palsy, unilateral or bilateral pupil dilation, ataxia
Lesion above the red nucleus causes?
flexor posturing
Flexor posturing is also known as?
Upper pontine damage signs of dysfunction are?
impaired consciousness, extensor posturing, irregular and apneustic respiration, abducens palsy or horizontal gaze palsy, bilateral small but reactive pupils
Lesion below the red nucleus results in?
extensor posturing
Extensor posturing also known as?
Horizontal gaze palsy is caused by damage to? How do you name the palsy?
PPRF; named for the side that the pt can't look towards
Which area of brain stem damage has a better prognosis?
upper midbrain damage
Which area of the brain stem has a worse prognosis?
upper pontine damage
Signs of dysfunction in the medulla are?
respiratory arrest, vertigo, nausea, ataxia, vomiting, autonomic instability, hiccups
Do medulla lesions have a good prognosis?
Lateral medullary syndrome also known as? Caused by?
Wallenburg Syndrome; PICA infarct
What is involved in Wallenburg syndrome?
lateral tegmentum, not too much motor affected, prognosis is good
Damage to inferior cerebellar peduncles causes?
ipsilateral ataxia
Damage to vestibular nuclei causes?
vertigo, nausea, nystagmus
Damage to CN5 nucleus and tract causes?
ipsilateral facial loss of pain and temperature sensation
Damage to nucleus ambiguus causes?
hoarseness and dysphagia
Damage to nucleus solitarius causes?
ipsilateral decreased taste
Damage to descending SNS tract causes?
ipsilateral Horner's syndrome
Damage to spinothalamic tract (ALS system) causes?
contralateral body decreased pain and temperature sensation
A lesion in the medial pontine base is caused by? Also called what?
lacunar disease; ataxic hemiparesis
What side is the ataxia on with a medial pontine base lesion?
ataxia is same side as the weakness
Vascular supply to the para-median pontine base is?
paramedian branches of the basilar artery, ventral territory
If the corticospinal tract is damaged, what are the clincal features?
UMN; contralateral leg and arm weakness
If the corticobulbar tract is damaged, what are the clincal features?
contralateral face weakness with dysarthria
If the corticobulbar tract is damaged, can the pt close their eye on the affected side?
yes, but not as tight as the eye on the unaffected side
Is corticobulbar tract an UMN or LMN?
If the abducens nerve is damaged, what are the clinical signs?
ipsilateral paralysis of lateral rectus
If the pontine nuclei and pontocerebellar tract are damaged, what are the clinical signs?
contralateral ataxia
Pontocerebellar tract fibers are called?
mossy fibers
Which cerebellar peduncle is the major input to the cerebellum?
middle cerebellar peduncle
What's found in the middle cerebellar peduncle?
pontocerebellar axons
Lesions in the midbrain are caused by infarcts in the?
PCA and the vessels from the top of the basilar artery
What is lesioned in oculomotor nerve palsy? Is damage above or below the nucleus?
CN3; damage below nucleus
What are the clincal symptoms with oculomotor nerve palsy
deviation of eye down and out, drooping of eyelid, dilated nonresponsive pupil
If lesion is at level of midbrain and cerebral peduncle, what are the clincal symptoms?
oculomotor nerve palsy and contralateral UMN paralysis
What is the major output of the cerebellum? Where is this output traveling to?
superior cerebellar peduncle; thalamus
What is the folia of the cerebellum?
cortex; three layers
Where is the cerebellum located?
dorsal to midbrain and pons
What is the main function of the cerebellum?
regulates movement and posture indirectly by adjusting the output of the major descending motor systems
How does the cerebellum act as a comparator?
by comparing intention with performance and compensates for errors in movement
How does the cerebellum correct movement?
corrects ongoing movements when they deviate from intended course and modifies the central program so the next movement can fulfill the intended goal
Cerebellum affects what aspects of movements?
rate, range, force, and direction
Lesions to the cerebellum cause?
What is ataxia?
uncoordinated and disorganized movements
What three things is the cerebellum not required for?
sensory perception, movement of muscles, development of muscle strength
How many hemispheres does the cerebellum have and what divides them?
2; midline vermis
What is the function of the primary fissure in the cerebellum?
divides it into anterior and posterior lobes
What is the roof of the 4th ventricle?
What deep cerebellar nucleus is found in the cerebrocerebellum?
What is the significance of the pineal gland?
calcifies with age and can be used as a landmark on XRAY or CT
How does a tumor on the pineal gland affect the patient?
Patient won't be able to look up
What are the two components of the spinocerebellum?
vermis and paramedian
What divides the posterior lobe from the flocculonodular lobe?
posterolateral lobe
The flocculus and nodulus help control? Are in close connection with?
balance and eye movement; vestibular system
What can cause the tonsils to herniate through the foramen magnum?
increased intracranial pressure, brain swelling, mass lesions of the cerebrum or cerebellum
What is the function of the cerebrocerebellum?
complex motor planning; influences planning for the corticospinal system
What is the function of the paramedian part of the spinocerebellum?
influences lateral motor tracts and distal limb coordination
What is the function of the vermis part of the spinocerebellum?
influences the medial motor tract and proximal limb and trunk coordination
What is the function of the vestibulocerebellum or flocculonodular lobe?
balance, posture, and VOR
All of the output of the cerebellar cortex is transmitted by?
purkinje cells to the deep cerebellar nuclei
Axons from the purkinje cells form what type of synapses with the deep cerebellar nuclei and vestibular nuclei?
Incoming cerebellar inputs via mossy and climbing fibers are ______ to the deep cerebellar nuclei?
All output from the cerebellum is from the?
deep cerebellar nuclei or "roof nuclei"
Lateral to medial what are the names of the deep cerebellar nuclei?
dentate, emboliform, globose, fastigial
What is the largest deep cerebellar nuclei? Where does it receive input from? What is it involved with?
dentate, cerebrocerebellum, motor planning; active just prior to voluntary movement
What are the interposed deep cerebellar nuclei?
emboliform and globose
Where do the interposed nuclei receive input from? What type of movement are they involved with? When are they active?
spinocerebellum, movement of appendages, active during and in relation to voluntary movement
Where does the fastigial deep cerebellar nuceli receive input from? What type of movement is this nucleus involved with?
spinocerebellum (vermis section) and vestibulocerebellum; trunk coordination and proximal limb movement
What other nucleus functions as a deep cerebellar nuclei?
vestibular nuclei
Where does the vestibular nuclei receive input from? What is this nuclei involved with?
direct from the vestibulocerebellum; balance and VOR