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Neuro Anatomy > Week 4 Learning Issues Part 1 > Flashcards

Week 4 Learning Issues Part 1 Flashcards

1
Q

Caudal brainstem contains which divisions

A

medulla, pons, and midbrain

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2
Q

cd brainstem receives input from

A

SA and VA from PNS (via cranial nerves) and input from special sense organs

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3
Q

cd brainstem contains ___ neurons

A

efferent neurons that control that control motor fxs and is involved in relatively basic reflex fxs
contains neuron populations involved in more complex processing of somatic and visceral information as well as UMNs which control motor activity in brainstem and spinal cord LMNs

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4
Q

clinical relevance cd brainstem

A

important in controlling respiration, cardiovascular fx and gait

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5
Q

D to V division cd brainstem

A

tectum (midbrain), tegmentum (rostral continuation of spinal cord runs throughout all 3 divisions), and ventral pons

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6
Q

tegmentum relative to tectum and v pons

A

tectum D to tegmentum in midbrain/ mesencephalon and ventral pons is ventral to tegmentum in pons/ metencephalon

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7
Q

tegmentum path

A

continuous structure that spans length cd brainstem; no abrupt changes in structure of tegmentum at transition between medulla, pons, and midbrain and functional neuron populations within tegmentum may span multiple brain divisions

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8
Q

cd brainstem neuron groups

A 
discrete nuclear groups:
CN nuclei
Tectum and pretectal nuclei
projection nuclei
red nucleus
Reticular formation
- origin of reticulospinal tracts
- neurocircuitry coordinating visceral and homeostatic functions
- ascending reticular activating system
- monoamine pathways
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9
Q

Tectum (Rostral and Caudal Colliculi) and Pretectal nuclei

A

involved in visual and auditory processing

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10
Q

projection nuclei

A

synaptic stations along sensory pathways to cerebellum and cortex

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11
Q

red nucleus

A

UMNs of rubrospinal tract involved in voluntary movement

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12
Q

reticular formation

A

contains many neuron populations that are more diffusely organized

  • origin of reticulospinal tracts
  • neurocircuitry coordinating visceral and homeostatic functions
  • ascending reticular activating system
  • monoamine pathways

The reticular formation is a histological distinction
It spans medulla, pons, and midbrain
Is a rostral extension of intermediate gray of spinal cord but more developed

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13
Q

origin of reticulospinal tracts

A

UMNs involved in locomotion

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14
Q

neurocircuitry coordinating visceral and homeostatic fxs

A

ex. brainstem micturition center, respiratory center and cardiovascular center

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15
Q

ascending reticular activating system

A

ARAS monoaminergic neurons involved in arousal, maintaining consciousness, sleep/ wake cycle and attention

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16
Q

monoamine pathways

A

modulate activity in sensory and motor pathway

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17
Q

reticular formation histological vs functional entity

A
  • composed of neurons not included in major nuclear groups of brainstem bc neurons don’t form tight clusters with clear boundaries; there are distinct neuron populations w diff fxs, morphology, and neurochemistry although not histologically visible
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18
Q

axon tracts cd brainstem

A
  • neurons in forebrain project to cd brainstem, cerebellum, and spinal cord to control motor activity and regulate sensory processing
  • neurons in spinal cord send axons carrying sensory info to cd brainstem, cerebellum, and forebrain
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19
Q

medial lemniscus

A

axon tract running through cd brainstem; carry proprioceptive information to forebrain

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20
Q

crus cerebri, longitudinal fibers of pons, and pyramids

A

axon tract running through cd brainstem; carry motor information to spinal cord

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21
Q

medial longitudinal fasciculus

A

axon tract running through cd brainstem; associated with vestibular system

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22
Q

axon tracts running through cd brainstem

A

medial lemniscus, crus cerebri, longitudinal fibers of pons, pyramids, and medial longitudinal fasciculus

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23
Q

pathways that travel through caudal brainstem to get where they are going

A

locomotion, postural reactions, and conscious perception of sensory stimuli

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24
Q

hypoglossal nucleus location

A

caudal medulla, ventral to 4th ventricle

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25
Q

path of hypoglossal nerve

A
  • hypoglossal nucleus
  • ventrally through medulla
  • lateral to pyramids as rootlets
  • rootlets merge at hypoglossal canal forming hypoglossal nerve
  • exit skull cd to TOF (hypoglossal canal)
  • courses medial to mandibular salivary gland
  • enters tongue adjacent to lingual artery
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26
Q

CN XI nucleus

A
  • spinal accessory nucleus

- LMNs in spinal cord segments C1-C7

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27
Q

CN XI path

A
  • spinal accessory nucleus
  • rootlets exit lateral cervical spinal cord
  • roots travel crly lateral to spinal cord
  • roots merge to form CN XI
  • foramen magnum
  • lateral to medulla
  • jugular formamen
  • TOF
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28
Q

CN IX nuclei

A
  • nucleus of the solitary tract (VA)
  • parasympathetic nucleus of CN IX (VE)
  • Nucleus ambiguous (SE)
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29
Q

Nucleus of solitary tract

A
  • extends from rostral to cd medulla; just v to 4th ventricle
  • only VA nucleus of brainstem; important for autonomic fx
  • receives VA information from CN IX, X, and spinal cord (via symp pathways)
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30
Q

Nucleus of solitary tract CN X

A
  • Afferent neurons carry visceral sensory info from sensory receptors in pharynx, larynx, trachea, esophagus, and thoracic and abdominal viscera
  • VA neuron cell bodies in distal ganglia of the vagus
  • enter medulla laterally via TOF
  • jugular foramen
  • enter brainstem at lateral medulla
  • synapse in nucleus of solitary tract ( medulla)
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31
Q

distal ganglion of the vagus

A

near the TOF

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32
Q

Nucleus of solitary tract CN IX

A
  • Afferent neurons carry visceral sensory info from sensory receptors in cd tongue and pharyngeal muosa and baro and chemoreceptors in proximal neck
  • cell bodies in glossopharyngeal ganglion
  • TOF
  • Jugular foramen
  • Enter brainstem at lateral medulla
  • synapse in nucleus of solitary tract (medulla)
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33
Q

glossopharyngeal ganglion

A

near TOF

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34
Q

nucleus of solitary tract and autonomic reflexes and functions

A

projects to brainstem reticular formation and other CN nuclei (PNX, NA) to mediate these

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35
Q

nucleus of solitary tract and higher level processing of visceral sensory information

A

projects to hypothalamus and thalamus for this

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36
Q

parasympathetic nucleus CN X location

A
  • located in dorsal caudal medulla, runs from mid to cd medulla
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37
Q

parasympathetic nucleus CN X path

???

A
  • 1st neuron parasympathetic nucleus CN X (dorsal cd medulla)
  • enter medulla laterally via TOF
  • jugular foramen
  • enter brainstem at lateral medulla
  • synapse in nucleus of solitary tract ( medulla)
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38
Q

Parasympathetic nucleus CN IX

A
  • cell bodies in parasympathetic nucleus CN IX
  • Axons enter crainial cavity via Tympanooccipital Fissure -Jugular Foramen
  • Enter brainstem at lateral medulla
  • Synapse in Nucleus of the Solitary Tract
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39
Q

Nucleus ambiguus

A
  • LMN cell bodies for X and IX innervation skeletal muscles of pharynx, larynx, esophagus here (these are skeletal muscles involved in swallowing, gagging, breathing, and vocalizing)
  • Ventrolateral location in medulla runs from mid to cd medulla
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40
Q

Path from nucleus ambiguus

A
  • Nucleus ambiguus located in medulla
  • axons emerge from lateral aspect medulla and contribute to CN IX and X
  • exit skull via jug formamen -TOF
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41
Q

LMNs that innervate skeletal muscles of pharynx

A

via CN IX

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42
Q

LMNs that innervate skeletal muscles pharynx, larynx, and esophagus

A

via CN X

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43
Q

endoscopic evaluation of laryngeal function can identify a CN __ deificit

A

CN X

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44
Q

gag reflex

A
  • afferents from cd tongue (IX), pharynx (IX and X), and larynx (X) travel in CNs IX and X and synapse in nucleus of solitary tract
  • reflex center in medulla
  • somatic efferents from nucleus ambiguous travel in CN IX and X -> elevation of the palate, contraction of pharynx and larynx, and sometimes retching (involves more than CN IX and X)
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45
Q

autonomic and respiratory fx

A
  • visceral sensory info carried on CN X and CN IX processed in autonomic regulatory centers in cd brainstem
  • regulate important physiological fxs including respiration, maintanece blood pressure, HR
  • nucleus solitary tract and parasympathetic nucleus of CN X= pt of these regulatory centers
  • severe lesions cd brainstem -> autonomic and respiratory dysfunction but many non-neuron causes can -> these issues too so not useful for lesion localizing
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46
Q

Nuclei of CN V

A
  • Trigeminal sensory nuclear complex

- motor nucleus of trigeminal nerve

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47
Q

Trigeminal sensory nuclear complex

A
  • 3 CN nuclei that receive sensory info from branches trigemnial nerve span cd brainstem
  • axons carrying input nociceptors travel cdly w/ in brainstem and synapse in medulla
  • axons carrying input mechanoreceptors synapse in pons
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48
Q

trigeminal sensory nuclei in medulla and pons involvedin

A

local brainstem reflexes (palpebral, corneal, facial twitching in response to facial stimulation) involve interneuron connections between trigeminal sensory and facial motor nuclei

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49
Q

trigeminal nuceli project via

A

trigeminal-thalmic tract -> forebrain for conscious perception higher level processing of sensory info from face

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50
Q

somatic sensory fx CN V

A

mechanoreception, nociception, thermoception, proprioception
- sensory input from face, oral, and nasal cavities and jaw carried to CNS via pseudo unipolar neurons w. cell bodies in trigeminal ganglion

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51
Q

V1 path

A
  • enters cr cavity via orbital fissure
  • cavernous sinus
  • cell bodies in trigeminal ganglion (rostral tip PTB)
  • trigeminal canal (tip of PTB)
  • joins brainstem at lateral pons
  • synapse in trigeminal sensory nuclei (medulla, pons)
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52
Q

V2 path

A
  • enters cr cavity via round foramen
  • cavernous sinus
  • cell bodies in trigeminal ganglion (rostral tip PTB)
  • trigeminal canal (tip of PTB)
  • joins brainstem at lateral pons
  • synapse in trigeminal sensory nuclei (medulla, pons)
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53
Q

V3 SA path

A
  • enters cr cavity via oval foramen (cd to cavernous sinus)
  • cell bodies in trigeminal ganglion (rostral tip PTB)
  • trigeminal canal (tip of PTB)
  • joins brainstem at lateral pons
  • synapse in trigeminal sensory nuclei (medulla, pons)
  • ** DOES NOT GO THROUGH CAVERNOUS SINUS***
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54
Q

motor nucleus of trigeminal nerve

A

located in pons

- contains LMN cell bodies for muscles mastication

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55
Q

V3 SE path

A
  • LMN cell bodies in motor nucleus of trigeminal nerve in pons
  • LMN axons run through trigeminal canal in PTB
  • Exit skull via oval foramen as part of V3
  • ** DOES NOT GO THROUGH CAVERNOUS SINUS***
56
Q

Facial nerve nuclei

A
  • Facial nucleus
  • parasympathetic nucleus of CN VII
  • trigeminal sensory nuclei
57
Q

facial nucleus

A
  • located in rostral ventral medulla

- cell bodies of LMNs to muscles of facial expression and cd digastrics

58
Q

CN VII path

A
  • LMNs in facial nucleus in rostral ventral medulla
  • axons exit brainstem at lateral aspect trapezoid body
  • axons enter petrous temporal bone via internal acoustic meatus
  • through petrous temporal bone (via facial canal) and middle ear (near ossicles in dorsal middle ear)
  • exit skull via stylomastoid foramen (cd to external acoustic meatus)
  • courses ventrolateral to horizontal ear canal
  • at cd border of masseter muscle divides into auriculopalpebral and dorsal and ventral buccal branches
59
Q

parasympathetic nucleus CN VII

A

in rostral medulla

- contains parasympathetic VE neurons to lacrimal and nasal glands, mandibular and sublingual salivary glands

60
Q

trigeminal sensory nuclei

A

sensory neurons from skin on concave surface of pinna synapse here

61
Q

CN VII dry eye

A

seen with lesions of CN VII axons to lacrimal gland split form CN VII within PTB so only very proximal facial nerve lesions will present with decreased tear production

62
Q

trigeminal-facial reflex loop

A
  • blink or twitch of lips, face, whiskers, ear ect = normal response
  • behavioral response like pulling head back or pawing at stimulus = conscious perception of sensory stimulation ie conformation that pathway from stimulated branch trigeminal nerve to trigeminal sensory nuclei to contralateral thalamus and cerebral hemisphere is in tact
63
Q

CN II nuclei

A
  • suprachiasmatic nucleus
  • lateral geiculate nucleus (LGN)
  • rostral colliculus
  • pretectal nuclei
64
Q

suprachiasmatic nucleus

A
  • hypothalamus

- entrainment of circadian rhythms

65
Q

lateral geniculate nucleus (LGN)

A
  • thalamus

- relays info from visual cortex for conscious perception and higher level processing

66
Q

rostral colliculus

A
  • tectum
  • visual orienting response
  • connections to CNs III, IV, VI to control eye movements toward visual targets
  • tectospinal tract controls movement of head to turn toward visual targets
67
Q

pretectal nuclei

A
  • located at junction rostral mesencephalon and cd diencephalon
  • mediates PLR via connections to parasympathetic nucleus CN III
68
Q

optic chiasm

A

greater than half of the axons in each optic nerve cross to travel in optic tract on contralateral side here

69
Q

CN II path

A
  • optic nerve enters cr cavity via optic canal
  • optic chiasma at Jnx rostral and middle cr fossa
  • optic tract (lateral aspect diencephalon)
  • termination: LGN of thalamus, pretectal nuclei, rostral colliculus, suprachiasmatic nucleus
70
Q

PLR pathway decussates

A

at both the optic chasm and the midbrain

71
Q

pathway for PLR

A
  • optic nerve
  • optic tract
    -optic chiasm (some axons stay in optic nerve and tact on same side some cross to contralateral side via optic chiasma)
  • pretectal nuclei (ganglion cell axons carry visual info from 1 retina to both pretectal nuclei (at jxn rostral mesencephalon and cd diencephalon) )
  • pretectal nuclei project bilaterally into parasympathetic nucleus of CN III in midbrain
  • Cavernous sinus
    oribtal fissure
  • PN CN III contains parasympathetic preganglionic neurons that project via CN III to ciliary ganglion
  • post ganglionic neurons ciliary ganglio project to pupillary constrictor muscles to mediate pupil constriction
72
Q

direct PLR

A

light shined in one eye elicits pupillary constriction in same eye

73
Q

indirect or consensual PLR

A

light shined in one eye elicits pupillary constriction in opposite eye; occurs bc bilateral projections in PLR pathway (PLR pathway decussates at both optic chiasm and midbrain)

74
Q

horners syndrome

A

caused by interruption to sympathetic innervation of pupil, 3rd eyelid, and periorbital smooth muscle

75
Q

purpose of sympathetic innervation to eye

A

dilate pupil in response to threatening stimulus

76
Q

VE neurons in LH know threatening situation has occured

A

information comes from processing of visual, auditory, olfactory, and somatosensory nociceptive pathways and is relayed to autonomic control centers in hypothalamus and brainstem autonomic control centers then project to symp preganglionic neurons in LH spinal cord segments T1-T3

77
Q

Path symp innervation to eye

A
  • symp preganglionic neurons LH T1-T3
  • sympathetic trunk
  • cr cervical ganglion
  • TOF
  • carotid canal
  • cavernous sinus
  • orbital fissure
78
Q

3 nuclei containing LMNs to extraolcular muscles

A
  • Oculomotor nucleus
  • Trochlear nucleus
  • Abducent nucleus
79
Q

medial longitudinal fasciculus

A

MLF; interconnects oculomotor nucleus, trochlear nucleus, and abducens nucleus with each other, with vesicular nuclei and with LMNs in neck; interconnections permit coordination of eye movements and head movements

80
Q

Oculomotor nucleus location

A

rostral midbrain near midline v to periaqueductal grey

81
Q

CN III path

A
  • oculomotor nucleus
  • tegmentum
  • emerge from V midbrain medial to crus cerebri
  • cavernous sinus
  • orbital fissure
  • ventral rectus, dorsal rectus, medial rectus, ventral oblique, and levator palpebrea muscles
82
Q

trochlear nucleus location

A
  • cd midbrain in same location relative to periaqueductal grey (PAG) as oculomotor nucleus
83
Q

CN IV path

A
  • Trochlear nucleus
  • axons pass D around PAG
  • decussate in rostral medullary vellum (roof 4th ventricle rostral to cerebellum)
  • over lateral aspect midbrain
  • cavernous sinus
  • orbital fissure
  • dorsal oblique muscles
84
Q

Abducens nucleus location

A

rostral medulla near midline ventral to 4th ventricle

85
Q

CN VI path

A
  • abducens nucleus
  • tegementum
  • lateral to pyramids at level of trapezoid body
  • cavernous sinus
  • orbital fissure
  • lateral rectus and retractor bulbi muscles
86
Q

LMNs in oculomotor, trochlear, and abducens nuclei are controlled by

A

UMN projection from many areas of brain including vestibular nuclei, rostral colliculus, and motor cortex

87
Q

parasympathetic nucleus CN III

A

located medial to oculomotor nucleus (rostral midbrain near midline v to periaqueductal grey)

88
Q

path through parasympathetic nucleus CN III

A
  • parasympathetic nucleus CN III
  • axons travel as part CN III (cavernous sinus -> orbital fissure)
  • synapse in ciliary ganglion w/ in periorbita
  • postganglionic neurons form ciliary nerves which innervate ciliary muscles and pupillary constrictors
89
Q

normal eye position depends on

A

intact vesicular system and MLF as well as CNs III, IV, and VI

90
Q

strabismus

A

deviation form normal eye position; occurs with normal head position suggesting lesion to LMN (cell body or axon)

91
Q

oculomotor damage -> strabismus

A

ventrolateral strabismus

92
Q

trochlear damage -> strabismus

A

rotated (cat vs calf)

93
Q

abducens damage -> strabismus

A

medial strabismus

94
Q

positional strabismus

A

occurs when head moved into certain position; suggests lesion affecting MLF or vestibular nuclei

95
Q

normal VOR

A
  • move animals head side to side eyes move in opposite direct as head so gaze is fixed
  • depends on intact vestibular system, intact MLF, and functioning LMNs to extra ocular muscles
96
Q

resting nystagmus

A

oscillating moevement of eye occurs spontaneously with head in normal position

97
Q

positional nystagmus

A

occurs when head moved into certain positions

98
Q

resting and positional nystagmus suggest

A

a lesion affecting the vestibular system or cerebellum bc damaged vestibular system is reporting head movements that are not occurring and eye movement system is generating eye movements based on faulty input

99
Q

visual following

A

tests CN II visual pathways through cerebral cortex, descending pathways from cerebrum to brainstem, cerebellum and CNs III, IV, and VI

100
Q

vestibular nuclei location

A

located in rostral medulla slightly cd and immediately medial to cd cerebellar peduncle

101
Q

auditory system

A
  • hair cells in cochlea transduce auditory stimulus and release neurotransmitter onto dendrites of primary afferent neurons
  • cell bodies of primary afferents in spiral ganglion in PTB
  • through PTB
  • internal acoustic meatus
  • join brainstem at level of trapezoid body
  • synapse on cochlear nuclei in rostral medulla
102
Q

auditory information used locally

A

in brainstem for more reflexive types of behavior such as auditory orienting

103
Q

unilateral auditory deficits

A

difficult to detect, animal with lesion in PTB, brainstem, or forebrain that disrupts auditory pathway patient will like present for more noticeable and serious problems than hearing loss

104
Q

vestibular apparatus

A
  • located within PTB
  • bony labyrinth (semicircular canals and the vestibule) houses epithelial lined membranous labrynth (composed of semicircular ducts and saccule and utricle)
  • filled with endolymph (fluid that flows within the ducts in response to movements of the head)
105
Q

endolymph

A

movement of endolymph detected by hair like processes of specialized receptor cells (hair cells) located in ampullae of semicircular canals; hair cells release neurotransmitter from their basal surface onto vestibular afferents

106
Q

primary vestibular afferents

A
  • dendrites near basal surface of hair cells of vestibular apparatus
  • cell bodies located w/ in vestibular ganglion in PTB
  • axons join those of auditory afferents run through PTB -> int acoustic meautus into cr cavity
  • fibers enter brainstem at level trapezoid body to synapse in vestibular nuclei and cerebellum
107
Q

where do primary vestibular afferents synapse in cerebellum

A

flocculonodular lobe and vermis

108
Q

vestibular apparatus detects

A

acceleration and rotation of head

109
Q

semicircular canals

A

oriented to be in 3 perpendicular planes so they can encode angular rotation of the head

110
Q

semicircular canals on L and R of head

A

designed to function in pairs based on orientation in common plane

111
Q

movement exciting vestibular afferents from semicircular duct on one side

A

inhibits vestibular afferents from paired duct on opposite side; this info is then conveyed to the vestibular nuclei (ie rotation head to right increases activity in vestibular afferents on right and decreases activity in vestibular afferents on left based on how hair cells respond to movement)

112
Q

vestibular nuclei gives rise to what 3 major motor pathways

A
  • Medial vestibulospinal tract/ pathway
  • lateral vestibulospinal tract/ pathway
  • pathway for vestibule-ocular reflex (VOR)
113
Q

medial vestibulospinal tract/ pathway location

A
  • projects bilaterally to cervical spinal cord via MLF and ventromedial funicilus
114
Q

Medial vestibulospinal tract/ pathway fx

A

provides innervation to the neck muscles that control head position; controls movements of head for maintaining posture and balance

115
Q

lateral vestibulospinal tract/ pathway location

A
  • projects ipsilaterally to all levels spinal cord via ventromedial funiculus
  • excites LMNs to ipsilateral axial and proximal limb extensors and inhibits lens innervating ipsilateral flexors
116
Q

lateral vestibulospinal tract/ pathway fx

A
  • turning or tilting head in one direct increases activity in ipsilateral vestibular nucleus which produces increased ipsilateral extensor tone to maintain balance
  • pathway also facilitates ipsilateral stretch reflex for extensor muscles and inhibits contralateral stretch reflex
117
Q

lesions involving vestibular nuclei can afffect

A

general muscle tone and stretch reflexes (bc lateral vestibulospinal tract/ pathway facilitates ipsilateral stretch reflex for extensor muscles and inhibits contralateral stretch reflex)

118
Q

vestibular nuclei projects

A

into brainstem for reticular formation vomitting center and to cerebral cortex for conscious perception of head position movement and higher level motor processing

119
Q

Pathway for VOR

A
  • from vestibular nuclei on either side travels rostrally in medial longitudinal fasciculus (MLF) to synapse:
  • excitatory synapse on ipsilateral oculomotor nucleus (controls MR)
  • excitatory synapse on contralateral abducens nucleus (controls LR)
120
Q

VOR activity in vestibular nuclei on either side

A

drives eyes in the contralateral direction

121
Q

in absence of head movement vestibular nuclei

A

have baseline level of activity balanced so eyes look straight ahead; if head rotates in horizontal plane eyes will move in contralateral direction

122
Q

nystagmus

A
  • normal phenomenon that exists to maintain appropriate eye position in face of large rotational movements of head
  • 2 phases slow phase and fast phase
123
Q

slow phase of nystagmus

A

at beginning of head movement eyes move with equal velocity as head but in opposite direction to keep image stabilized on retina; this stage is slow phase of nystagmus which is VOR

124
Q

fast phase of nystagmus

A

head continues to move eyes reach maximal excursion and can no longer maintain the stationary image a fast eye movement occurs to fix gaze at new central location
this is not dependent on VOR pathway

125
Q

nystagmus naming

A

named for direction of fast phase should name it nystagmus with slow phase to left and/ or fast phase to the right rather than right nystagmus

126
Q

when cavity in vestibular nuclei on either side of brain is balanced

A

motor input to postural muscles on both sides of body is equal ; equal activity in vestibular nuclei results in equal stimulation of medial and lateral rectus muscles for both eyes

127
Q

lesion that causes unilateral damage to vestibular apparatus, vestibular nerve, or vestibular nuclei in brainstem

A

will cause an imbalance in the system resulting in somewhat predictable movements of the eyes and postural muscles

128
Q

lesion of vestibular apparatus, nerve or nucleus may cause abnormal nystagmus with slow phase

A

directed toward the lesion; nystagmus is initiated by the VOR

129
Q

when lesion abolishes activity in the vestibular apparatus, nerve, or nuclei on one side

A

the baseline cavity on the other side is unopposed -> VOR toward side of lesion followed by a fast eye movement away from lesion when eyes reach their maximal excursion in orbit

130
Q

patient with lesion of vestibular apparatus, nerve, or nuclei often presents with

A

loss of balance including a tendency to fall, turn (tight circles) or demonstrate a head tilt toward the side of the lesion largely bc decreased extensor tone on side of the lesion; if vestibular apparatus nerve or nucleus on one side is no longer active there is loss of excitatory input to ipsilateral extensors of limbs via lateral vestibulospinal tract; contralateral limb will still have extensor tone

131
Q

cerebellum plays a critical role in

A

maintenance of posture and in control of eye movements; combines vestibular input with input from many systems including the visual system and proprioceptors in the limbs, trunk, neck, and eye muscles; determines appropriate movement and feedback to vestibular nuclei to influence their output

132
Q

axons from cerebellum to vestibular nuclei

A

travel in caudal cerebellar peduncle

133
Q

effect of the cerebellum on the vestibular nuclei

A

is inhibitory

134
Q

unilateral lesion of cerebellum or cd cerebellar peduncle can result in Turing/ tiltiing/ falling ___ from the side of the lesion

A

away; this = paradoxical vestibular dx bc clinical signs relative to lesion are reversed; rather than diminishing activity in the vestibular nuclei the cerebellar lesion releases the vestibular nuclei from inhibition resulting in increased activity in vestibular pathways ipsilateral to cerebellar lesion

135
Q

peripheral vestibular dx

A

refers to problem affecting PNS components of vestibular system (vestibular apparatus and vestibular nerve)

136
Q

central vestibular dx

A

refers to problem affecting CNS components of vestibular system (vestibular nuclei, cd cerebellar peduncle, and cerebellum)

Neuro Anatomy (17 decks)

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