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224 Cards in this Set

  • Front
  • Back
A right cerebellar lesion will cause ataxia on which side?
right; ipsilateral
What is appendicular ataxia?
uncoordinated limbs; caused by lateral cerebellar lesions
A lesion to the cerebellar vermis will cause ataxia of what structures?
medial areas like trunk, eyes, vertigo
Largest structure in the posterior fossa
cerebellum
The primary fissure separates _____ from ______
posterior lobe and anterior lobe of cerebellum
The ________ is the most inferior portion of the cerebellar vermis
nodulus
Superior cerebellar peduncle (aka brachium conjunctivum)
carries mainly outputs from the cerebellum
middle cerebellar peduncle (aka brachium conjunctivum)
carries mainly inputs to the cerebellum
inferior cerebellar peduncles (aka restiform body)
carries mainly inputs to the cerebellum
Function: Lateral hemisphere
Motor planning for extremities
Motor pathways influences: Lateral hemisphere
lateral cortico spinal tract
Function: Intermediate hemisphere
distal limb coordination
Motor pathways influenced: Intermediate hemisphere
lateral corticospinal tract, rubospinal tract
Function: Vermis
Proximal limb and trunk coordination
Motor pathways influenced: Vermis
anterior corticospinal tract, reticulospinal tract, vestibulospinal tract, tectospinal tract
Function: flocculonodular lobe
balance and vestibulo-ocular reflex
Motor pathways: flocculonodular lobe
medial longitudinal fasiculus
Cerebellar tonsilar herniation causes almost immediate death due to compression of what structure?
respiratory centers of the medulla
A patient with vertigo most likely has a problem with which part of the cerebellum?
vermis or flocculonodular lobes
All outputs from the cerebellum relay through which 4 nuclei?
Deep cerebellar nuclei (Dentate, Emboliform, Globose, Fastigial)
List the 4 deep cerebellar nuclei form lateral to medial
Dentate, Emboliform, Globose, Fastigial
Dentate nuclei
Most lateral of the deep nuclei; largest of the deep nuclei; receive projections from the lateral cerebellar hemispheres
The emboliform and globose nuclei are together called ________
interposed nuclei
Interposed nuclei
receive input from the intermediate part of the cerebellar hemispheres
Fastigial nuclei
receive input from the veris and a small input from the flocculonodular lobe
3 layers of the cerebellar cortex (superficial to deep)
Molecular, Purkinje, Granular
What is found within the molecular cell layer of the cerebellum?
unmyelinated granule cell axons, Purkinje cell dendrites, and several types of interneurons
2 Cerebellar input tracts
Mossy fibers and Climbing fibers
Mossy fibers
Ascend through the cerebellar white matter to form excitatory synapses onto dendrites of the granule cells --> form parallel fibers that run parallel to the folia --> excite purkinje cells
Output from the cerebellar cortex is brought to the deep cerebellar nuclei via what fibers?
Purkinje
Function: Purkinje Cells
Form inhibitory synapses onto the deep cerebellar nuclei and vestibular nuclei, which then convey outputs from the cerebellm to other regions through excitatory synapses
Golgi cells are found in which cell layer of the cerebellum?
granular
What are cerebellar parallel fibers?
found in the molecular layer; from the granule cells of the input fibers (Mossy and Climbing)
Mossy fibers activate which cell layer of the cerebellum?
granular cells which activate inhibitory Purkinje cells
Climbing fibers activate which cell layer of the cerebellum?
inhibitory Purkinje fibers
4 inhibitory descending axons from the cerebellar cortex
Purkinje, stellate, basket and Golgi cells
Why do cerebellar lesions result in ipsilateral deficits?
the motor systems from cerebellum are double crossed
From where to climbing fibers arise?
the contralateral inferior olivatory nulcues
Golgi Cells
Provide feedback inhibition onto the granule cells; this inhibitory feedback tends to shorten the duration of excitatory inputs to the granule cells (enhanced signal resolution in the time domain)
Stellate and basket cells
narrow the spatial extent of excitatory inputs to Purkinje cells (enhanced signal resolution in the spatial domain)
Cerebellar Glomerulus
contain axons and dendrites encapsulated in a glial sheath; contain two types of inputs (large mossy fiber axon terminals and Golgi cell axon terminals), which form synapses onto one type of postsynaptic cell (granule cell dendrites)
Are the deep cerebellar nuclei excitatory or inhibitory?
excitatory
Lateral cerebellar lesions
affect mainly distal limb coordination
Medial cerebellar lesions
affect mainly trunk control, posture, balance, and gait
2 places where cerebellar motor tracts cross
superior cerebellar peduncle decussation+ pyramidal decussation or ventral tegmental descussion; DOUBLE CROSSED - deficits in coordination occur ipsilateral to the lesion
Lesions in the cerebellar vermis
Do not typically cause unilateral deficits because the medial motor systems influence proximal trunk mucles bilaterally
Deep nuclei of the lateral hemisphere
Dentate nucleus
Cerebellar peduncle of the lateral hemisphere
superior cerebellar peduncle
Output Targets of lateral hemispheres
Ventrolateral nucleus of thalamus (VL), parvocellular red nucleus
Deep nuclei of intermediate hemipshere
interposed nuclei (emboliform + globose)
Cerebellar peduncle of intermediate hemisphere
superior cerebellar peduncle
Output target of intermediate hemisphere
VL, magnocellular red nucleus
Deep nuclei of vermis
Fastigial nucleus
Cerebellar peduncle of Vermis
superior cerebellar peduncle, uncinate fasiculus, juxtarestiform body
Output targets of vermis
reticular formation, vestibular nuclei
Deep nuclei of inferior vermis and flocculonodular lobe
vestibular nuclei
Cerebellar peduncle of inferior vermis and flocculonodular lobe
juxtarestiform body
Output targets of inferior vermis and flocculonodular lobe
medial longitudinal fasiculus (eye movement pathways)
Output signals come from the motor cortex, to the cerebellar deep nuclei to what structure next?
thalamus (VL), red nucleus or MLF
From the dentate nucleus, where does the output signal go next?
thalamus (VL)
From the vestibular nucleus in the cerebellum, where does the output signal go next?
MLF
Uncinate fasiculus
loops over the superior cerebellar peduncle and then sends fibers to continu caudally via the contralateral juxtarestiform body to reach the contralateral vestibular nulclei
Reciprocal connections between the cerebellum and vestibular nuclei are important for what?
equilibrium and balance
Inputs of the cerebellum
(1) virtually all areas of the cerebral cortex (2) multiple sensory modalities, including visual, auditory, and somatosensory systems (3) brainstem nuclei (4) spinal cord
The cerebellum receives input from the cortex via which fibers?
corticopontine (from the frontal, temporal, parietal, and occipital lobes that travel in the internal capsule and cerebral peduncles)
Pontine nuclei
scattered areas of gray matter in the ventral pons interspersed among the descending corticospinal and corticobulbar tracts
The pontocerebellar fibers reach the cerebellum via _______ through the _______ cerebellar peduncle
pontine nuclei; middle
4 spinocerebellar tracts
Dorsal, ventral, rostral and cuneocerebellar tracts
A patient with damage to the cuneocerebellar tract will have decreased coordination in which part of the body?
upper extremity
A patient with damage to the dorsal spinocerebellar tract will have decreased coordination in which part of the body?
lower extremity
Afferent information about limb movements is conveyed to the cerebellum by the ________ tract for the lower extremity and by the ______ tract for the upper extremity and neck
dorsal spinocerebellar; cuneocerebellar cerebellar
Information about activity f spinal cord interneurons, thought to reflect the amount of activity in descending pathways, is carried by the _______ tract for lower extremitites and _______ tract for lower extremities
ventral spinocerebellar; rostral spinocerebellar
Main Origins of Input: Doral Spinocerebellar Tract
leg proprioceptors
Main Origin of Input: Cuneocerebellar Tract
Arm proptioceptors
Main Origin of Input: Ventral Spinocerebellar Tract
Leg interneurons
Main Origin of Input: Rostral Spinocerebellar Tract
Arm interneurons
Nucleus dorsalis of Clark
long column of cells that run in the dorsomedial spinal cord gray matter intermediate zone, from C8 to L2 or L3; Fibers ascending from here ascend ipsilaterally in the dorsal spinocerebellar tract; these fibers give rise to mossy fibers that travel to the ipsilateral cerebellar cortex via inferior cerebellar peduncle
Cerebellar penduncle: Dorsal spinocerebellar tract
inferior cerebellar peduncle
External cuneate nucleus
located in the medulla, just lateral to the cuneate nucleus; site of cells for cuneocerebellar fibers
Cerebellar peduncle: Cuneocerebellar tract
inferior cerebellar peduncle
The ventral spinocerebellar tract arises from ______
spinal border cells
Cerebellar peduncle: Ventral spinocerebellar tract
superior cerebellar peduncle
Cerebellar peduncle: Rostral spinocerebellar tract
superior and inferior cerebellar peduncle
Corticopontine fibers travel to (ipsilateral or contralateral) pons?
ipsilateral
Pontocerebellar fibers travel from the pons to the (ipsilateral or contralateral) cerebellum?
contralateral middle cerebellar peduncle
The nucleus Dorsalis of Clark sends sensory innervation to the cerebellum (inferior peduncle) via which tract?
dorsal spinocerebellar, then become Mossy fibers
3 major arteries to the cerbellum
PICA, SCA, AICA
The PICA usually arises from _______
the vertebral artery
The AICA usually arises from _______
the lower basilar artery
The SCA usually arises from _____
the top of the basilar artery, just below the posterior cerebral artery
The PICA supplies
the lateral medulla, most of the inferior half of the cerebellum, and the inferior vermis
The AICA supplies
the inferior lateral pons, the middle cerebellar peduncle, and a strip of ventral (anterior) cerebellum between the territories of the PICA and SCA, including the flocculus
The SCA supplies
the upper lateral pons, the superior cerebellar peduncle, most of the superior half of the cerebellar hemisphere, including the deep cerebellar nuclei, and the superior vermis
An infarct that involves just the cerebellum itself is most like in which cerebellar artery?
SCA
Infarcts of the lateral pons or medulla that spare the cerebellum most often occur in which arteries?
PICA and AICA
Large cerebellar infarcts in the PICA or SCA
can cause swelling of the cerebellum --> hydrocephalus due to compression of 4th ventricle
Presentation of cerebellar hemorrhage
headache, nausea, vomiting, vertigo, possible hydrocephalus + 6th nerve palsies and impaired consciousness
Fatal gastroenteritis
cerebellar hemorrhage that initially presents with only GI symptoms of nausea and vomiting
Tx hydrocephalus due to hemorrage
ventriculostomy; this carries risk of upward transtentorial herniation as the posterior fossa hemorrhage and edema expand
Ataxia
disordered contractions of agonist and antagonist muscles and the lack of normal coordination between movements at different joints, seen in patients with cerebellum dysfunction
dysrhythmia
ataxic movments with abnormal times
dysmetria
abnormal projections through space (over or undershooting)
Lesions confined to the ________ affect primarily the medial motor systems
cerebellar vermis
Gait associated to vermis lesions
wide-based, unsteady, "drunk-like"; Truncal ataxia
Ataxia associated with intermediate and lateral portions of cerebellum
appendicular ataxia
Ataxia associated with unilateral lesion in the lateral portion of the cerebellum
No appreciable deficit
Lesions of the cerebellar hemispheres cause (ipsilateral, contralateral, bilateral) symptoms in the extremities
ipsilateral
Lesions of the cerebellar peduncles cause (ipsilateral, contralateral, bilateral) deficits
ipsilateral
Cerebellar lesions affected the medial motor system cause (ipsilateral, contralateral, bilateral)
bilateral (truncal ataxia)
What is ataxia-hemiparesis?
ataxia along with motor loss; internal capsule lesions affect corticospinal tract and corticopontine fibers both; often caused by lacunar infarcts
In ataxia hemiparesis, the ataxia is usually (contralateral, ipsilateral) to the lesion and the hemiparesis is usually (contralateral, ipsilateral) to the lesion
contralateral, contralateral
Causes of ataxia-hemiparesis
lesions in the corona radiata, internal capsule, or pons that both involve corticospinal and corticopontine fibers (however, it can also be seen in thr frontal lobes, parietal lobes, or sensorimotor cortex, or in midbrain lesions that involve fibers of the superior cerebellar peduncles or red nucleus)
Sensory Ataxia
occurs when the posterior-column-medial lemniscal pathways is disrupted, resulting in loss of joint position sense
Sensory Ataxia is made worse by
closing the eyes
Cause of Sensory Ataxia
lesions of peripheral nerves or posterior column
Is sensory ataxia ipsilateral or contralateral to the lesion?
ipsilateral if due to lesion in peripheral nerves/posterior column, but can be contralateral if lesion is found in thalamus, thalamic radiations, or somatosensory cortex
Symptoms of Cerebellar Disorders
nausea, vomiting, vertigo, slurred speech, unsteadiness, or uncoordinated limb movements; headache may occur in the occipital, frontal, or upper cervical area; hydrocephalus and head tilt
The finger-to-nose test
the patient touches their nose and then the examiner's finger alternately; tests for ataxia
Heel-shin test
The patient rubs one heel up and down the length of the opposite shin in as straight of a line as possible; variations include tapping the heel repeatedly ont he same spot
Tests for dysrhythmia
Rapid tapping of fingers together, of the and on the thigh or of foot on the floor
Dysdiadochokinesia
abnormalities of rapid alternating movements, such as alternately tapping one hand with the palm and dorsum of the other hand
Testing for overshoot
have the pt raise both arms suddenly from their lap or lower them suddently to the level of the examiners hand
Postural tremor
occurs when the limg muscles are activated to hold a particular position
Tandem gait
the heel touches the toe with each each, forcing the patient to assume a narrow stance (tests truncal ataxia)
The Romberg test checks for (truncal or appendicular ataxia)?
truncal
titubation
tremor or the trunk or head associated with midline lesions
Nysagmus
when the patient looks toward a target in their periphery, slow phases occur toward the primary position and fast phases occur back toward the target; unlike the nystagmus in peripheral vertigo, the nysagmus in cerebellar lesions may change directions, depending on the direction of gaze; vertical nysagmus may be present in cerebellar disorders
Scanning or Explosive Speech
Ataxic quality of speech with irregular fluctuations in rate and volume; associated with cerebellar disorders
A patient has inability to touch their finger to their nose. This is (truncal or appendicular ataxia)?
appendicular ataxia
Most common causes of acute ataxia in adults
toxin ingestion and ischemic or hemmoragic stroke
Common causes of chronic ataxia in adults
cerebrovascular disease, brain metastases, chronic toxin exposure (medications, alcohol), MS, degenerative disorders of the cerebellum
Acute Ataxia in children
accidental drug ingestion, varicella-associated cerebellitis, migraine
Chronic ataxia in children
cerebellar astrocytoma, medulloblastoma, Friedreich's ataxia, ataxia-tenagiectasia
Hereditary Ataxia Syndromes
sponocerebellar ataxia (SCA); gene defects encoding polyglutamine trinucleitide repeats
eye movement abnormaliities localize to ___ (2) of cerebellum
vermis

flocculonodular lobe
2 lobes of cerebellum

they are separated by ___
anterior

posterior

primary fissure
___ fissure is visible only on ventral surface of cerebellum
posterolateral
posterolateral fissure separates ___ from ___
flocculonodular lobes

posterior lobe
flocculus is medial/lateral to nodulus

the 2 are connected via ___
lateral

pedicles
tonsillar herniation is bad because of ___
compression of medulla, compromising respiratory centers
superior cerebellar peduncle decussates at level of ___

it primarily carries ___

it is aka ___
inferior colliculi

cerebellar outputs

brachium conjunctivum
middle cerebellar peduncle primarily carries ___

it is aka ___
cerebellar inputs

brachium pontis
inferior cerebellar peduncle primarily carries ___

it is aka ___
cerebellar inputs

restiform body
intermediate hemispheres do ___
appendicular coordination
vermis/flocculonodular lobes do ___ (2)
axial coordination

vestibulo-ocular coordination
deep cerebellar nuclei from lateral to medial

___ are largest
dentate

emboliform

globose

fastigial

dentate
___ comprise the interposed nuclei
emboliform

globose
___ is active before voluntary movements

___ is active during voluntary movements
dentate

interposed
dentate nuclei receive inputs from ___
lateral cerebellar hemispheres
interposed nuclei receive inputs from ___
intermediate cerebellar hemispheres
fastigial nuclei receive inputs from ___
vermis

flocculonodular lobe
cerebellar cortex has ___ layers
3
3 layers of cerebellar cortex from deep to superficial
granule cell layer

purkinje cell layer

molecular layer
molecular layer contains ___ (3)
granule cell axons

purkinje cell dendrites

interneurons
2 kinds of cerebellar input fiber types
mossy fibers

climbing fibers
mossy fibers synapse on ___s
granule cells
granule cell axons give off ___s in the molecular layer
parallel fibers
parallel fibers run in plane of ___ and perpendicular to ___, with which they synapse
surface of folium

dendrites of purkinje cells
synapses from parallel fibers to purkinje cells are excitatory/inhibitory
excitatory
purkinje cells synapse on ___s
deep nuclei
synapses from purkinje cells on deep nuclei are excitatory/inhibitory
inhibitory
climbing fibers start in ___
contralateral inferior olivary nucleus
climbing fibers grow along axon of ___
purkinje cell
climbing fibers synapse on approximately ___ purkinje cells
10
synapse from climbing fiber on purkinje cell is excitatory/inhibitory
excitatory
each purkinje cells receives synapses from ___ climbing fibers
1
3 kinds of cerebellar interneurons
stellate

Golgi

basket
stellate cells are located in ___ layer

Golgi cells are located in ___ layer

basket cells are located in ___ layer
molecular

granule cell

molecular
basket fibers have dendrites oriented ___ly

their axons terminate on ___

this does ___
perpendicular to parallel fibers of molecular layer

purkinje cells

lateral inhibition of purkinje cells
golgi cells receive inputs from ___

their axons terminate on ___

this does ___
parallel fibers of molecular layer

granule cells

feedback inhibition on granule cells
cerebellar glomeruli are located in ___ layer
granule cell
cerebellar glomeruli have ___ (2) as inputs and ___ as terminus
mossy fiber

golgi cell axon

granule cell dendrite
on microscopy, cerebellar glomeruli look like ___s
clearings among granule cells
lesions of ___ cerebellum cause ipsilateral deficit because of ___
lateral and intermediate

both input and output pathways involve double decussation
all cerebellar output pathways project to ___ (2)
cortex

medulla
cerebellar outputs project to cortex through ___
contralateral VL pars caudalis of thalamus
VL projects to ___ (5) cortices
motor

premotor

SMA

parietal lobe

PFC
lateral and intermediate cerebellar output projects to medulla through ___
contralateral red nucleus
lateral cerebellar outputs all project through ___
dentate nucleus
lateral cerebellar outputs project from dentate nucleus to medulla through ___
parvocellular red nucleus
parvocellular red nucleus is the ___ part
rostral
intermediate cerebellar outputs all project through ___
interposed nuclei
intermediate cerebellar outputs project to medulla through ___
magnocellular red nucleus
magnocellular red nucleus gives rise to ___
rubrospinal tract
parvocellular red nucleus projects to ___ in medulla via ___
inferior olivary nucleus

central tegmental tract
first neuron in triangle of Guillain-Mollaret has soma in ___ and projects to ___
lateral cerebellum

dentate nucleus
2nd neuron in triangle of Guillain-Mollaret has soma in ___ and projects vis ___ to ___
dentate nucleus

superior cerebellar peduncle

contralateral parvocellular red nucleus
3rd neuron in triangle of Guillain-Mollaret has soma in ___ and projects via ___ to ___
parvocellular red nucleus

central tegmental tract

inferior olivary nucleus
4th neuron in triangle of Guillain-Mollaret has soma in ___ and projects via ___ to ___
inferior olivary nucleus

inferior cerebellar peduncle (climbing fibers)

contralateral lateral cerebellum
triangle of Guillain-Mollaret is aka ___
myoclonic triangle
lesion of triangle of Guillain-Mollaret can cause ___ which presents with ___
hypertrophic olivary degeneration

palatal myoclonus
T/F: projections from lateral and intermediate cerebellum go to distinct parts of VL
TRUE
2 kinds of medial cerebellar outputs
superior vermis

inferior vermis + flocculonodular lobe
cerebellar outputs from superior vermis all project through ___
fastigial nuclei
cerebellar outputs from superior vermis project to ipsilateral medulla via ___ and contralateral medulla via ___
juxtarestiform body

uncinate fasciculus
superior vermis projects to ___ in ipsilateral medulla
vestibular nuclei

reticular formation
superior vermis projects to ___ in contralateral medulla
vestibular nuclei
juxtarestiform body is visible at ___
lateral wall of 4th ventricle
inferior cerebellum and flocculonodular lobe all project via ___ to ___
juxtarestiform body

ipsilateral vestibular nuclei
T/F: no cerebellar outputs project to lower motor neurons
false: some fastigial projection to upper C cord
all cerebellar inputs except those from ___ are via ___
inferior olivary nuclei

mossy fibers
cerebellar inputs from inferior olivary nucleus are carried via ___
climibing fibers
cortical inputs to cerebellum project first to ___
ipsilateral pontine nuclei
pontine nuclei project to contralateral cerebellum via ___
middle cerebellar peduncle
spinal inputs to cerebellum travel via ___
spinocerebellar tracts
4 spinocerebellar tracts
dorsal SCT

cuneocerebellar tract

ventral SCT

rostral SCT
dorsal SCT carries inputs from ___
leg proprioceptors
ventral SCT carries inputs from ___
leg interneurons
rostral SCT carries inputs from ___
arm interneurons
cuneocerebellar tract carries inputs from ___
arm proprioceptors
soma of 1st neuron in dorsal SCT is in ___

it projects to ___ (2)
leg DRG proprioceptor

fasciculus gracilis

nucleus dorsalis of clark
nucleus dorsalis of clark is located at ___ (on axial slice)

its rostro-caudal extent is from ___ to ___
antero-medial aspect of posterior grey horn

C8

L2 or L3
soma of 2nd neuron in dorsal SCT is in ___

it projects via ___ to ___
nucleus dorsalis of clark

inferior cerebellar peduncle

ipsilateral cerebellar cortex
in spinal cord, dorsal SCT runs in the ___
dorsolateral funiculus
soma of 1st neuron in cuneocerebellar tract is in ___

it projects via ___ to ___
arm DRG proprioceptor

fasciculus cuneatus

external nucleus cuneatus
soma of 2nd neuron in cuneocerebellar tract is in ___

it projects via ___ to ___
external nucleus cuneatus

inferior cerebellar peduncle

ipsilateral cerebellar cortex
soma of 1st neuron in ventral SCT tract is in ___ (2)

it projects via ___ to ___
spinal border cells

intermediate zone

superior cerebellar peduncle

ipsilateral cerebellar cortex
spinal border cells are located in ___
outer edge of central grey
ventral SCT decussates at ___
AWC and after entering cerebellum via superior peduncle
anterior aspect of cerebellum is primarily perfused by ___
AICA
posterior cerebellum is primarily perfused by ___
SCA and PICA
cerebellar infarcts occur primarily in ___ (2) territories
SCA

PICA
cerebellar infarcts sparing the brainstem are primarily in ___ territory
SCA
5 extra-cerebellar lesions which cause ataxia (or similar symptoms)
pons

PFC

lacunar ataxia hemiparesis

dorsal column (sensory ataxia)

other SC