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cerebellum
cerebellum
197
Anatomy
Graduate
04/25/2012

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Term
what are the 2 lateral parts of the cerebellum?
Definition
cerebrocerebellum
Term
what is the part of the cerebellum that is in the middle when it's in your brain but is on the bottom when you unfold it?
Definition
vestibulocerebellum
Term
anatomically, what is another term for the vestibulocerebellum?
Definition
flocculus and nodulus
Term
what is the center part of the cerebellum?
Definition
spinocerebellum
Term
what are the 3 parts of the spinocerebellum
Definition
vermis surrounded on 2 lateral sides by paramedian
Term
describe the main homonculus of the cerebellum
Definition
upside down person. Ipsilateral
Term
which part of the cerebellum contains the upside down homonculus
Definition
spinocerebellum
Term
which part of the cerebellum is important for trunkal musculature
Definition
vermis
Term
which part of the cerebellum is important for distal musculature
Definition
paramedian
Term
what are the three major paths for things going in or out of the cerebellum
Definition
superior cerebellar peduncle, middle cerebellar peduncle, inferior cerebellar peduncle
Term
which cerebellar peduncle is an afferent pathway for things coming in
Definition
middle
Term
which cerebellar peduncle is an efferent pathway for things going out
Definition
superior
Term
which cerebellar peduncle is a pathway both for things leaving and entering the cerebellum
Definition
inferior
Term
what is the deep cerebellar nucleus in each cerebrocerebellum
Definition
dentate
Term
what is the deep cerebellar nucleus in each paramedian
Definition
interposed nucleus
Term
what is the deep cerebellar nucleus in the vermal portion of the cerebellum
Definition
fastigial
Term
to where does the cerebrocerebellum always project information
Definition
dentate
Term
to where does the paramedian always project information
Definition
interposed nucleus
Term
to where does the vermis always project information
Definition
fastigial nucleus
Term
to where does the vestibulocerebellum project information
Definition
either the fastigial nucleus or the vestibular nuclei
Term
where in the cerebellum are purkinje cells located
Definition
at the surface/cortex
Term
to where do purkinje cells project
Definition
to a deep nucleus of the cerebellum
Term
if I am a purkinje cell in the cerebrocerebellum to where do I project
Definition
dentate
Term
if I am a purkinje cell in the floccus/nodulus/vestibulocerebellum, to where do I project
Definition
fastigial or vestibular nuclei
Term
do axonal projections from the cerebellum synapse on LMNs or interneurons in the spinal cord?
Definition
no
Term
if the cerebellar axons don't synapse on LMNs or interneurons, how does it influence movements
Definition
by modulating the activity patterns of UMNs
Term
to where does the cerebellum send axonal projections
Definition
to virtually all UMN pathways
Term
what 2 types of information goes to the cerebellum
Definition
sensory information about what kind of movements are occurring; information about planned movement
Term
from where does the cerebellum receive information about the initiation and planning of skilled movements?
Definition
cerebral cortex
Term
from where does the cerebellum receive information about the course of movements that are occurring
Definition
from the sensory systems (proprioception and vestibular)
Term
how is the cerebellum a comparator
Definition
it compares entended movements with actual movements
Term
what is the function of the cerebellum
Definition
reduce motor errors
Term
to where in the cerebellum is information about motor planning as well as sensory information projected to
Definition
purkinje cells in the cerebellar cortex
Term
what do purkinje cells do following reception of motor planning and sensory information
Definition
purkinje cells project a correction signal of intended vs. actual movements to the deep nuclei
Term
what do the deep nuclei of the cerebellum do upon receipt of a correction signal from purkinje cells
Definition
deep nuclei then project the correction signal to modulate the activity of UMNs
Term
when does the cerebellum analyze and correct movements
Definition
all day long
Term
can you move without your cerebellum?
Definition
yes, just not very well
Term
describe purkinje cells
Definition
large cells with extensive dendrites located in the cortex of the cerebellum
Term
what are the most abundant cells in the human brain
Definition
granule cells
Term
what are parallel fibers
Definition
specialized axons from granule cells
Term
what type of fibers are the majority of afferent/incoming fibers to the cerebellum?
Definition
mossy fibers
Term
what type of fibers wrap themselves around purkinje fibers?
Definition
climbing fibers
Term
where do climbing fibers come from
Definition
olive
Term
what do we call afferent axons from the inferior olive
Definition
climbing fibers
Term
what do we call afferent axons to the cerebellum from the pons, spinal cord, and vestibular nuclei
Definition
mossy fibers
Term
what do mossy fibers synapse on in the cerebellum
Definition
granule cells
Term
what do the axons of granule cells give rise to
Definition
parallel fibers
Term
what is the outermost layer of the cerebellar cortex
Definition
molecular layer
Term
why are granule axons called parallel fibers when they split
Definition
because they run parallel to each other
Term
what do parallel fibers do
Definition
send excitatory input over to dendrites of purkinje fibers
Term
is the excitatory input that parallel fibers give to purkinje fibers weak or strong
Definition
weak
Term
how can the weak excitatory input from parallel fibers excite purkinje fibers
Definition
because of their extensive dendrites, purkinje fibers can receive input from over 10,000 parallel fibers
Term
along with parallel fibers, from what other fibers do purkinjes receive excitatory synapses
Definition
climbing fibers
Term
is the excitatory input that climibing fibers give to purkinje fibers weak or strong
Definition
strong
Term
where do purkinje fibers project
Definition
deep cerebellar nuclei
Term
are purkinje cells excitatory or inhibitory
Definition
GABAnergically inhibitory
Term
is the output of the cerebellar cortex excitatory or inhibitory
Definition
inhibitory
Term
what do purkinje cells do to the deep cerebellar nuclei
Definition
inhibit them
Term
from what do deep cerebellar nuclei receive excitatory synapses
Definition
collateral branches of mossy and climbing fibers
Term
what modulates the excitation of the deep cerebellar nuclei from the mossy and climbing fibers?
Definition
purkinje cells
Term
is purkinje cell excitation from mossy fibers direct or indirect
Definition
indiret
Term
how is purkinje cell excitation from mossy fibers indirect
Definition
mossy fibres synapse on granules, whose axons bifurcate into parallel fibers and synapse on purkinje cells
Term
what are the 2 sources of excitatory input on purkinje cells from outside the cerebellum
Definition
mossy fibers, climbing fibers
Term
is purkinje cell excitation from climbing fibers direct or indirect
Definition
direct
Term
what gives rise to the output/efferent fibers of the cerebellum?
Definition
purkinje cells
Term
what is the correction signal to the deep nuclei of the cerebellum
Definition
inhibitory impulses from purkinje cells
Term
describe dr k's family with purkinje cells, mossy fibers, climbing fibers, and deep cerebellar nuclei
Definition
Dr. K is a deep cerebellar nucleus. His daughters are climbing and mossy fibers. They ask him for something, and he says yes. They ask his wife (purkinje cell), and she tells him he has to say no. So he compromises and tones down his original yes.
Term
describe the formation of correction signal from purkinje, climbing, mossy fibers
Definition
an input to the cerebellum sends excitatory information to the deep nuclei through collaterals of the climbing and mossy fibers. A short time later, the deep nuclei receives processed inhibitory information from the purkinje cells, which were also excitied by the climbing and mossy fibers. What leaves the deep nuclei are correction signals that leave the cerebellum to modulate the activity of UMNs throughout the brain and spinal cord.
Term
what happens to information that enters the cerebellum
Definition
it comes back out altered/corrected
Term
what are the 5 principle functions of the cerebellum
Definition
1. compares planned movement with actual movement and makes error corrections. 2. relies on sensory/feedback information to optimize movements. 3. coordinates equilibrium, posture, and eye movements. 4. plans and learns certain coordinated skilled movements. 5. together with the basal ganglia, regulates and modifies motor performance
Term
what does the cerebellum rely on to optimize movement
Definition
sensory information/feedback
Term
if we could unfold the cerebellum from the brainstem, what would be the 3 anatomical regions of the cerebellum
Definition
anterior lobe, posterior lobe, flocconodular lobe
Term
what other brain structure is developed from the same part of the embryological neural tube as the cerebellum
Definition
pons
Term
what is the central (vertical) region of the cerebellum
Definition
vermis
Term
what do we call the 2 lateral parts of the cerebellum
Definition
hemispheres
Term
what are the 3 fissures of the cerebellum
Definition
primary, horizontal, posterior
Term
what are the 3 major components of the cerebellum
Definition
cerebellar cortex, deep cerebellar nuclei, cerebellar peduncles
Term
what is the cerebellar cortex
Definition
the overlying outer cortical region made of gray matter
Term
what travels through the cerebellar peduncles
Definition
all incoming and outgoing information to/from the cerebellum (axon tracts)
Term
what type of pathway is the superior cerebellar peduncel
Definition
primarily an efferent pathway (output axons)
Term
what type of pathway is the middle cerebellar peduncle
Definition
afferent (input axons)
Term
where do the afferent axons that go to the cerebellum through the middle peduncle come from
Definition
contralateral pons
Term
what type of pathway is the inferior cerebellar peduncle
Definition
afferent and efferent
Term
about how many neurons go into each side of the cerebellum
Definition
about 20 million
Term
from what 4 major anatomical areas does the cerebellum receive input
Definition
cerebrum, vestibular nuclei, spinal cord, inferior olive
Term
from what cerebral cortices does the cerebellum receive input
Definition
frontal/parietal cortices
Term
what are the fibers that carry input to the cerebellum from the vestibular nuclei, spinal cord, and cortices/cerebrum
Definition
mossy fibers
Term
through which peduncles does afferent information travel to get to the cerebellum
Definition
middle and inferior peduncles
Term
what are the output targets of the cerebellum
Definition
locations of where UMN pathways originate
Term
what are the 5 output targets of the cerebellum
Definition
red nucleus, vestibular nuclei, superior colliculus, reticular formation, motor cortex (via thalamus VA/VL nuclei)
Term
describe the cerebellar cortex
Definition
similar to cerebral cortex: contain cell bodies overlying deeper white matter
Term
what are folia
Definition
extensive folds in the cerebellar cortex that increase surface area
Term
what are the 3 functional areas of the cortex of the cerebellum
Definition
cerebrocerebellum, vestibulocerebellum, spinocerebellum
Term
what is the largest subdivision of the cerebellar cortex
Definition
cerebrocerebellum
Term
what is phylogenetically the oldest part of the cerebellum
Definition
vestibulocerebellum
Term
how are the subdivisions of the cerebellar cortex made/named
Definition
by their different sources of input
Term
from where does the cerebrocerebellum receive input
Definition
from many areas of the cerebral cortex
Term
in what kinds of animals is the cerebrocerebellum highly developed
Definition
primates
Term
what is the cerebrocerebellum concerned with
Definition
the planning and execution of highly skilled movements including speech: movement planning and learning
Term
which part of the cerebellum contains the flocculus and noddulus
Definition
vestibulocerebellum
Term
from where does the vestibulocerebellum receive input
Definition
vestibular nuclei
Term
what is the vestibulocerebellum primarily concerned with
Definition
the regulation of movements underlying posture and equilibrium; also regulates eye movement
Term
from where does the spinocerebellum receive input
Definition
from the spinal cord
Term
what is the spinocerebellum concerned with
Definition
ongoing execution of limb movement
Term
what is the lateral/paramedian part of the spinocerebellum concerned with
Definition
distal limb muscle movmeent
Term
what is the median/vermis part of the spinocerebellum concerned with
Definition
proximal muscle movements and eye movement
Term
what kind of info does the cerebrocerebellum get and from where
Definition
info from cerebrum about planning activity
Term
what kind of info does the vestibulocerebellum get and from where
Definition
from vestibular nuclei about where we are in space
Term
what kind of info does the spinocerebellum get and from where
Definition
from spinal cord about position of trunk/body/limbs
Term
is the somatotopic map of the cerebellum continuous or fractionated
Definition
fractionated
Term
what is the bottom line of the somatotopic map of the cerebellum
Definition
distal limbs are lateral, trunk is medial
Term
where are the deep cerebellar nuclei
Definition
embedded in white matter deep to the cerebellar cortex
Term
what are the deep cerebellar nuceli
Definition
dentate, interposed, fastigial
Term
from where do the deep cerebellar nuclei receive input
Definition
purkinje cells of the cerebellar cortex
Term
what do the neurons of the deep nuclei do
Definition
give rise to the major excitatory output pathways from the cerebellum
Term
what are the 2 nuclei that are a part of the interposed nuclei
Definition
globose and embiliform
Term
which of the deep cerebellar nuclei is the largest
Definition
dentate
Term
what part of the cerebellum projects to the dentate
Definition
cerebrocerebellum
Term
which part of the cerebellum project to the interposed and fastigial nuclei
Definition
spinocerebellum
Term
which part of the cerebellum projects to the fastigial and vestibular nuclei
Definition
vestibulocerebellum
Term
what are the 4 cerebellar pathways
Definition
olivocerebellar, cerebrocerebellar, spinocerebellar, vestibulocerebellar
Term
which of the cerebellar pathways integrates with the other 3
Definition
olivocerebellar
Term
how does the olivocerebellar pathway integrate with the other cerebellar pathways
Definition
our olive is always sending climbing fibers to all other pathways/parts of the cerebellum
Term
from where does the inferior olive receive descending information
Definition
the inferior olive receives descending information from the cerebral cortex, including motor and visual cortices as well as the red nucleus
Term
from where does the inferior olive receive ascending information
Definition
inferior olive receives ascending sensory and proprioceptive information from the limbs via spinolivary tracts
Term
once integrated, where does information that has been projected to the inferior olive go next?
Definition
all areas of the contralateral cerebellum
Term
through which peduncle does information travel from the inferior olive to the contralateral cerebellum
Definition
inferior cerebellar peduncle
Term
what kind of information does the inferior olive give to the cerebellum
Definition
information about actual and intended ongoing movements
Term
what do inferior olive projections to the cerebellum play an important role in
Definition
motor learning. When you learn new activities, this pathway works in overtime
Term
through what type of fibers does information travel on to go from the inferior olive to the cerebellum
Definition
climbing fibers
Term
when I have a motor plan to move a muscle, what is the path of the motor command to initiate voluntary movement (be general)
Definition
command is sent from the motor cortex to the muscle through the corticospinal tract
Term
when I have a motor plan to move a muscle, how does the plan also get to the cerebellum
Definition
the plan is projected from the cortex to the pontine nuclei. Fibers then project via the middle cerebellar peduncle to the cerebrocerebellum/purkinje cells
Term
what happens to the motor plan information in the cerebrocerebellum
Definition
the cerebrocerebellum analyzes the plan then generates a correction signal which is then projected to the dentate nucleus
Term
where does the correction signal in the cerebrocerebellum pathway go after reaching the dentate nucleus
Definition
the correction signal is projected via the superior cerebellar pathway to the contralateral VL thalamus and then back to the motor cortex to help adjust the motor command accordingly by adjusting UMN
Term
what are the steps of the input of the cerebrocerebellar pathway in detial
Definition
1. inputs to the cerebrocerebellum arise from motor/sensory cortical areas; 2. synapse in the pons/pontine nuclei; 3. axons decussate in pons (transverse pontine fibers); 4. these axons project to the cerebrocerebellum via MCP; 5.
Term
what are the steps of the output of the cerebrocerebellar pathway in detail
Definition
1. purkinje cells project the correction signal to the dentate nucleus; 2. dentate nucleus projects to contralateral VL nucleus of the thalamus via SCP; 3. thalamic axons project to cortex to initate/modulate UMN activity; 4. some axons project to the red nucleus and back to the olive as a feedback loop for motor learning
Term
what is the summary of the cerebrocerebellar pathway
Definition
information from the cerebral cortex is sent to the cerebellum. This information is integrated in the cerebellar cortex. Cerebellum projects the integrated information/correction signal back to the cerebral cortex and selects and adjusts planned and skilled motor movements
Term
what is another term for the cerebrocerebellar pathway
Definition
dentothalamic pathway
Term
what are the steps of the spinocerebellum pathway as I move my right let
Definition
1. proprioceptive information from the limbs and trunk ascend in the spinal cord through the dorsal spinocerebellar pathway and enter the spinocerebellum through the ICP. 2. spinocerebellum uses this afferent input to assess movement. 3. spinocerebellum generates a correction signal and sends it to the interposed and/or fastigial nuclei. 4. interposed nuclei relay the correction signal via the SCP to the contralateral VL thalamus and then to the motor cortex to adjust UMN and fastigial nucleus relays the correction signal to the brainstem via the ICP to adjust UMNs
Term
through what pathway does the correction signal go when leaving the interposed nucleus
Definition
SCP
Term
to where does the correction signal go when leaving the interposed nucleus
Definition
VL thalamus, then to motor cortex, then to lateral UMN pathways, then to distal musculature
Term
through which pathway does the correction signal go when leaving the fastigial nucleus
Definition
ICP
Term
to where does the correction signal go when leaving the fastigial nucleus
Definition
through ICP to brainstem to medial UMN pathways (reticulo and vestibulo) and then to axial musculature
Term
does the spinocerebellum only receive information through the spinocerebellum pathway
Definition
no, also through the olivocerebellar pathway
Term
does the interposed nucleus control distal or trunkal muscles
Definition
distal
Term
does the fastigial nucleus control distal or trunkal muscles
Definition
trunkal
Term
from where does the spinocerebellum receive somatosensory stimuli
Definition
spinal cord (clarke's and external cuneate nuclei) via the ICP
Term
what does the input to the spinocerebellum from the spinal cord tell the cerebellum
Definition
provides information to the cerebellum concerning fidelity of movement
Term
what is the output of the spinocerebellar pathway
Definition
via purkinje axons to the interposed and fastigial nuclei. Interposed axons project to the VL thalamus, then to corticosspinal UMNs to adjust distal muscles OR to red nucleus. Fastigial axons project to brainstem where UMN pathways influence distal muscles.
Term
what does the vestibulocerebellar pathway influence
Definition
posture, balance, eye movements
Term
what is the vestibulocerebellar pathway
Definition
1. sensory information concerning equilibrium and body position is conveyed to the vestibular nuclei via CN VIII. 2. this positional information is relayed to the vestibulocerebellum via the ICP. 3. the vestibulocerebellum generates a correction signal which is sent to the fastigial nucleus and vestibular nuclei. 4. fastigial output axons project via ICP to adjust the UMNs from vestibular nuceli to modulate posture/balance and extraocular muscles
Term
what is another term fro the vestibulocerebellar pathway
Definition
flocculonodular pathway
Term
from where and through which cerebellar pathway does the vestibulocerebellar pathway receive input
Definition
from the vestibular nuclei and CN VIII via the ICP
Term
to where do purkinje cells in the vestibulocerebellum relay the correction signal
Definition
to the vestibular and fastigial nuclei
Term
to where do fastigial output axons project
Definition
through ICP to modulate UMNs in vestibular nuclei (control posture/balance/eye motions)
Term
studying which system has enhanced our understanding of the contribution the cerebellum makes to motor error correction
Definition
oculomotor system
Term
If you partially cut the tendon of the left eye's lateral rectus muscle to weaken horizontal gaze in that eye AND you place a patch over the normal right eye, what is the initial effect of saccades performed by the left eye?
Definition
hypometric: undershoots the target because it is weakened
Term
if you partially cut the tendon of the left eye's lateral rectus muscle to weaken horizontal gaze in that eye AND you place a patch over the normal right eye, what is the effect of saccades performed by the left eye in about 5 days?
Definition
the amplitude of the left eye's saccades gradually increase until they are accurate
Term
if you partially cut the tendon of the left eye's lateral rectus muscle to weaken horizontal gaze in that eye AND you place a patch over the normal right eye for 5 days and THEN you remove the patch from the right eye and put it on the left eye, what is the effect of saccades performed by the right eye?
Definition
hypermetric: they overshoot
Term
in the lateral rectus muscle weakening/patch experiments, what is happening?
Definition
the CNS is correcting the errors made in saccades from the weak (left) eye by increasing the gain of the saccade motor system
Term
how is the cerebellum involved in the saccade motor system
Definition
the cerebellum sets the gain for the saccade motor system (and other motor systems) to make sure it is accurate. An intact cerebellum is required for smooth saccadic eye movements
Term
can folks with cerebellar disease make good saccadic eye movements?
Definition
no
Term
what is the VOR?
Definition
a simple reflex that keeps eyes fixed on a target while the head is moving
Term
what is the cerebellum's role in VOR?
Definition
error reduction
Term
describe the VOR
Definition
when a visual image on the retina shifts due to head movements, the eyes move in opposite direction to head movement at the same velocity so that the retinal image remainss table
Term
if a subject wears minifying glasses, altering the size of the image on the retina, what is the initial effect with the VOR
Definition
when the subject turns her head, her eyes will move the same distance as the head and at the same velocity, but they will be too large to keep the image on the retina because of the minifying glasses. They will overshoot the image.
Term
if a subject wears minifying glasses, altering the size of the image on the retina, what is the graduale effect with the VOR
Definition
subjects learn to adjust the distance the eyes must move in response to head movements in order to get accurate eye movements.
Term
if a subject wears minifying glasses, altering the size of the image on the retina, what happens to the gain?
Definition
the gain is reset
Term
if a subject wears minifying glasses, altering the size of the image on the retina, and then the subject removes the glasses, what is the effect?
Definition
the change in the gain is retained for a period of time following removal of the glasses. Your VOR will be out of register.
Term
where are the retained changes (after removing minimizing glasses) detected using electrophysiological recording
Definition
purkinje and deep nuclei neurons
Term
what does it mean that changes in VOR movements are retained?
Definition
the cerebellum is capable of motor learning and remembering.
Term
is the cerebellum capable of storing motor information?
Definition
yes
Term
what is the significance that the cerebellum can store motor information
Definition
as we develop, our cerebellum learns the activity and is able to store the activity inside the cerebellum. It motor learns and it motor remembers
Term
how does cerebellar damage affect movement
Definition
patients with cerebellar damage exhibit persistent errors in movement
Term
list 5 signs of cerebellar dysfunction
Definition
ataxia, nystagmus, action tremors, dysdiadochokinesia, vertigo
Term
what is ataxia
Definition
clumsiness
Term
what is nystagmus
Definition
eyes have difficulty maintaining fixation; they have involuntary, rhythmical, repeated oscillations of one or both eyes
Term
what are action tremors
Definition
over and undershooting of a target (inability to correct movements)
Term
what is dysdiadochokinesia
Definition
inability to perform alternating movements
Term
what is vertigo
Definition
dizziness characterized by sensation of spinning
Term
how do cerebellar problems affect agonist/antagonist muscle contractions
Definition
people with cerebellar problems have trouble coordinating agonist and antagonist muscles so the timing is off.
Term
what will be the result if you have cerebellar disease that affects trunkal and proximal muscles that help control gait
Definition
you'll walk with an altered gait
Term
describe the gait of someone with cerebellar problems
Definition
jumpy, staggered; from trunkal musculature
Term
how is a cerebellar gait different from a stroke gait
Definition
cerebellar is less predictable and standard
Term
if someone has cerebellar disease, how does their action tremor change as they get closer to their target
Definition
the closer they get to the target, the greater the amplitude of their tremor. As they get closer, they get more error. They can't filter out errors because of lesions in their cerebellum
Term
how to test for dysdiadochokinesia
Definition
as them to pronate/supinate their hands repeatedly and quickly. People with cerebellar disease have difficulty with this task
Term
what part of the cerebellum would contribute to vertigo if it was impaired
Definition
vestibulocerebellum
Term
if the cerebellum is damaged on one side, which side of the body will exhibit movement errors?
Definition
same side
Term
if one small area within the cerebellum is damaged, will it cause movement errors throughout the entire same side of the body?
Definition
probably not. Inputs to the cerebellum are represented topographically, so movement errors are very specific.
Term
what part of the cerebellum can chronic alcoholism affect
Definition
anterior cerebellum
Term
if someone's anterior cerebellum is damaged, what will be affected
Definition
lower limbs: results in staggering, ataxic gait. Arms not affected
Term
if the vermis is damaged, will you see unilateral or bilateral symptoms
Definition
bilateral, symmetrical symptoms.
Term
what happens if we lose part of the vestibulocerebellum
Definition
problems with posture, balance, and eye movements
Term
can cerebellar dysfunction cause difficulty performing planned motor skills/
Definition
yes
Term
what happens if someone gets a lesion to the lateral areas of the cerebrocerebellum
Definition
cerebrocerebellum is all about planning skilled motor activities, so they get action tremors and inability to do rapid alternating movements
Term
what kind of problems would someone have if their vermis is damaged
Definition
trunkal
Term
what kind of problems would someone have if they have a lesion to their paramedian
Definition
extremity issues
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