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78 Cards in this Set
- Front
- Back
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Anterior lobe of cerebellum somatotopic arrangement (top to bottom) |
leg, arm, head |
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Posterior lobe of cerebellum somatotopic arrangement (top to bottom) |
head, arm, leg |
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Vermis of cerebellum somatotopic set up |
information from auditory and visual cortex |
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Where do the afferent signals from the lateral lobes/cerebrocerebellum send information to? |
the cortex |
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Where does the cerebellum play a large role? |
in motor control and motor learning |
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What does the cerebellum mainly do? |
coordinates movement and postural control by comparing actual motor output with intended movement |
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What mechanisms does the cerebellum use? |
feed-forward and feedback mechanisms |
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What makes the cerebellum a unique structure? |
Input exceeds output and it is a highly integrative structure |
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What does the motor planning function of the cerebellum do? |
plans which muscles will be moving at what intensity and for how long |
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What does the position sense of the cerebellum do? |
compares intended movement with actual movements |
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What does the feedback function of the cerebellum do? |
messages the motor cortex to adjust movements |
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Describe the internal feedback tracts |
apprises the cerebellum of movement commands before it is received by the muscles |
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Describe the spinocerebellar tract |
it monitors the response of muscles to commands and does unconscious/automatic adjustments to movements and posture |
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What are the internal feedback tracts? |
rostrospinocerebellar tract and anterior (ventral) spinocerebellar tract (VSCT) |
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Where does the rostrospinocereellar tract transfer information? |
transmit info from cervical spinal cord to ipsilateral cerebellum |
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What is the path of the rostrocerebellar tract? |
it enters the cerebellum via the superior cerebellar peduncles |
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Where does the VSCT get information from? |
the thoracolumbar spinal cord (cell bodies in lateral and ventral horns) and both sides of lower body |
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What is the pathway for the VSCT? |
axons cross and ascend in contralateral antrior spinocerebellar tract to midbrain then enters the cerebellum via superior cerebellar peduncles (most fibers recross midline before entering cerebellum) |
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What would a brown sequard lesion of the cerebellum do? |
cause a loss in ability to monitor on contralateral side and loss of movement on ipsilateral side |
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What are the high fidelity (somatotopic) pathways? |
cuneocerebellar tract and posterior (dorsal) spinocerebellar tract (DCST) |
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What information do the high fidelity pathways manage? |
information about actual movements from muscle spindles, golgi tendon organs, and cutaneous mechanoreceptors |
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What is the travel path of the cuneocerebellar tract? |
primary afferents travel in dorsal columns to lower medulla, synapses in lateral cuneate nucleus, enters ipsilateral inferior cerebellar peduncle, and ends in cerebellar cortex |
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What is the travel path of the DCST? |
primary afferents travel in dorsal column to thoracic/upper lumbar spinal cord, synapses in nucleus dorsalis, and remains ipsilateral to cerebellar cortex |
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What forms the cuneocerebellar tract? |
second order neurons |
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What forms the posterior spinocerebellar tract? |
second order axons |
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Where are the input cerebellar pathways coming from? |
cerebral cortex, vestibular apparatus, vestibular and auditory nuclei, spinal cord (high fidelity pathways and itnernal feedback tracts), and descending motor tracks |
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Where are the output cerebellar pathways coming from? |
vestibulospinal, reticulospinal, rubrospinal, corticobrainstem, and corticospinal |
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What are the afferents of the medial/vermal zone? |
primary vestibular afferents and vestibular nuceli, reticular and pontine nuclei, and spinal cord (DSCT and VSCT) |
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What are the efferents of the medial/vermal zone? |
vestibulospinal tracts, reticulospinal tracts, medical corticospinal tract, and motor cortex via thalamus |
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What is the function of the medial/vermal zone? |
integrate spinal and vestibular inputs and influences important motor pathways for walking |
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What are the afferents of the intermediate/paravermal zone? |
DSCT and VSCT, reticular nuclei, and cerebral cortex via pontine nuclei |
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What are the efferents of the intermediate/paravermal zone? |
rubrospinal tract and lateral corticospinal tract |
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What is the function of the intermediate/paravermal zone? |
integrate spinal and cortical inputs and influences walking through motor cortical areas |
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What is the afferent for the lateral/cerebrocerebellum zone? |
cerebral cortex via pontine nuclei |
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What are the efferents of the lateral/cerebrocerebellum zone? |
lateral corticospinal tract, corticobrainstem tract, and rubrospinal tract |
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What is the function of the lateral/cerebrocerebellum zone? |
influence walking via cortical interactions and may be most important for voluntary modification of locomotor cycle |
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What are the afferents of the flocculonodular/vestibulocerebellar zone? |
primary vestibular afferents, vestibular nuclei, and reticular nuclei |
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What is the efferent of the flocculonodular/vestibulocerebellar zone? |
vestibular nuclei |
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What is the function of the flocculonodular/vestibulocerebellar zone? |
control of eye movements and balance |
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What is the afferent of the paraflocculus? |
vestibular and visual input |
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What are the functions of the cerebellum? |
equilibrium, gross movements of the limbs, and fine/distal/voluntary movements |
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How does the vestibulocerebellum help with equilibrium? |
It allows for smooth eye movements and coordinates responses to balance reactions |
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How does the spinocerebellum assist in gross movements of limbs? |
It coordinates postural adjustments and automatic movements |
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How does the cerebrocerebellum assist with fine/distal/voluntary movements? |
It coordinates voluntary fine motor movements in distal extremities and the planning of movements/timing |
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What neurons are active during stance and during swing? |
Stance: vestibular neurons Swing: reticular neurons |
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What increases during stance and during swing? |
Stance: increased extensor muscle activity Swing: increased flexor muscle activity |
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When is there the greatest and least amounts of activity of the intermediate zone? |
Greatest during transition between ipsilateral stance and swing phases, and least activity during midstance |
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What is the significant role of the lateral zone? |
It has a significant role in making adjustments when precise limb placement is necessary and visual guidance is required |
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What do anterior lobe lesions cause? |
- increased anterior posterior sway - hypermetric postural responses - postural tremor - increased intersegmental movements of head, trunk, and legs |
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What does anterior-posterior sway look like? |
high velocity, low amplitude movement going back and forth |
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What are examples of hypermetric postural responses? |
- overshooting the initial responses - larger than normal surface-reactive torque responses - exaggerated and prolonged muscle activity |
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Describe how omnidirectional sway looks |
low frequency, high amplitude in all directions - looks like a drunk sway |
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What balance deficits occur with cerebellar lesions? |
- cerebellar gait ataxia - reduced joint excursions - increased stride - stride variability in joint angles - decomposition between ankle and knee joints - reduced walking speed |
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What intersegmental coordination deficits occur with cerebellar lesions? |
- no gait ataxia - leg kinematics indistiguishable from control subjects on level surface - decomposition effect increases w/ incline or precision need |
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What contributes to cerebellar gait ataxia during uninterrupted level walking? |
balance deficits more than visually guided leg control deficits |
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How do cerebellar lesions affect feed-forward control? |
Makes patient unable to learn to use predictive feed-forward control to scale postural responses to expected perturbations |
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How do cerebellar lesions affect adaptation to sudden/predictable changes? |
Patients can adapt to changes in speed, but use individualized strategies |
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How do cerebellar lesions affect the 'podokinetic after-rotation' effect? |
Makes it so that patient has reduced amplitudes of after-rotation, diminished capacity to store novel orientation |
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What does the CNS have to generate? |
basic pattern of rhythmic reciprocal flexor and extensor muscle activity that makes up basic locomotor synergy |
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Where is basic synergy generated? |
brainstem and spinal cord |
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What does the cerebellum contribute to? |
- modulation of timing, rate, and force of muscle activity controlling pattern - maintains intersegmental and interlimb coordination |
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What does the CNS do with balance? |
Maintains control of equilibrium using feedforward and feedback mechanisms to maintain upright posture |
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What does cerebellum lesions impair in regards to balancce? |
- impaired sitting, standing, and walking balance - abnormal postural tone - frequent falling during locomotion |
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What happens when the cerebellar system fails with normal locomotion? |
gait ataxia occurs |
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Why does the CNS have to have adaptive capabilities for locomotor control? |
So that the basic pattern can be altered according to the demands of the environment or changes in behavioral goals |
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TIM VaDeTuCoNe |
T: trauma (TBI) I: inflammation (MS, cerebellitis, gluten ataxia) M: metabolic (hypothyroidism, gluten ataxia, toxicity) Va: vascular (stroke) De: degenerative (Friedrich's ataxia) Tu: tumor Co: congenital (chiaria malformation, agenesis, hypoplasia) Ne: neurogenic (idiopathic late-onset cerebellar ataxia) |
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What is Friedrich's ataxia? |
debilitating/life shortening, degenerative neuromuscular disorder, autosomal recessive, limits production of frataxin, causes neuronal degeneration |
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Symptoms of Friedrich's ataxia |
- ataxia in arms and legs - fatigue and weakness - loss of sensation - loss of vibration and position sense early on - aggressive scoliosis - others like vision/hearing impairment, DM, hypertrophic cardiomyopathy and arrhythmias |
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Prognosis of friedrich's ataxia |
- loss of ambulation 5 - 15 years after onset - average lifespan 30 - 40 years after diagnosis - cardiac dz and diabetes greatest risk |
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What is ataxia - telangiectasia? |
- complex, multisystem disorder characterized by progressive neurologic impairment - predominantly cerebellar form of spinocerebellar degeneration - delayed onset of incomplete pubertal development (early menopause) - autosomal recessive gene that affects DNA resistance to stress |
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Symptoms of ataxia - telangiectasia |
- relentlessly progressive - ataxia is notable early on - oculomotor apraxia (I can see it - can't grab it) - dysarthria/drooling - involuntary movements - signs of spinocerebellar degeneration w/ loss of DTRs and spinal muscle atrophy - other - weakens immune system, telangiectasia, DM, chronic lung dz |
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Prognosis of ataxia - telangiectasia |
- inability to walk by 10/11 y.o. - difficulty swallowing, poor nutrition, poor weight gain - life expectancy highly variable, approx. 25 years after diagnosis - most common causes of death are lung dz and cancer |
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What is common to all cerebellar lesions? |
- uncoordinated voluntary movement - normal strength - jerky - inaccurate |
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What part of the cerebellum is affected when there is truncal ataxia? |
flocculonodular lobe |
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What lesion is it when there is gait and limb ataxia? |
paravermal lesion |
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What lesion is it when there is hand ataxia? |
lateral cerebellar lesion |
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What tests help distinguish between cerebellar and somatosensory ataxia? |
- proprioception - vibration sense - ankle reflexes |
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What are the vestibulocerebellar symptoms? |
- nystagmus - dysequilibrium - difficulty maintaining sitting and standing balance (truncal ataxia) |
