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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 |
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A lesion to the cerebellar vermis will cause ataxia of what structures? |
medial areas like trunk, eyes, vertigo |
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Largest structure in the posterior fossa |
cerebellum |
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The primary fissure separates _____ from ______ |
posterior lobe and anterior lobe of cerebellum |
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The ________ is the most inferior portion of the cerebellar vermis |
nodulus |
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Superior cerebellar peduncle (aka brachium conjunctivum) |
carries mainly outputs from the cerebellum |
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middle cerebellar peduncle (aka brachium conjunctivum) |
carries mainly inputs to the cerebellum |
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inferior cerebellar peduncles (aka restiform body) |
carries mainly inputs to the cerebellum |
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Function: Lateral hemisphere |
Motor planning for extremities |
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Motor pathways influences: Lateral hemisphere |
lateral cortico spinal tract |
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Function: Intermediate hemisphere |
distal limb coordination |
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Motor pathways influenced: Intermediate hemisphere |
lateral corticospinal tract, rubospinal tract |
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Function: Vermis |
Proximal limb and trunk coordination |
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Motor pathways influenced: Vermis |
anterior corticospinal tract, reticulospinal tract, vestibulospinal tract, tectospinal tract |
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Function: flocculonodular lobe |
balance and vestibulo-ocular reflex |
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Motor pathways: flocculonodular lobe |
medial longitudinal fasiculus |
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Cerebellar tonsilar herniation causes almost immediate death due to compression of what structure? |
respiratory centers of the medulla |
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A patient with vertigo most likely has a problem with which part of the cerebellum? |
vermis or flocculonodular lobes |
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All outputs from the cerebellum relay through which 4 nuclei? |
Deep cerebellar nuclei (Dentate, Emboliform, Globose, Fastigial) |
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List the 4 deep cerebellar nuclei form lateral to medial |
Dentate, Emboliform, Globose, Fastigial |
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Dentate nuclei |
Most lateral of the deep nuclei; largest of the deep nuclei; receive projections from the lateral cerebellar hemispheres |
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The emboliform and globose nuclei are together called ________ |
interposed nuclei |
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Interposed nuclei |
receive input from the intermediate part of the cerebellar hemispheres |
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Fastigial nuclei |
receive input from the veris and a small input from the flocculonodular lobe |
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3 layers of the cerebellar cortex (superficial to deep) |
Molecular, Purkinje, Granular |
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What is found within the molecular cell layer of the cerebellum? |
unmyelinated granule cell axons, Purkinje cell dendrites, and several types of interneurons |
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2 Cerebellar input tracts |
Mossy fibers and Climbing fibers |
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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 |
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Output from the cerebellar cortex is brought to the deep cerebellar nuclei via what fibers? |
Purkinje |
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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 |
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Golgi cells are found in which cell layer of the cerebellum? |
granular |
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What are cerebellar parallel fibers? |
found in the molecular layer; from the granule cells of the input fibers (Mossy and Climbing) |
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Mossy fibers activate which cell layer of the cerebellum? |
granular cells which activate inhibitory Purkinje cells |
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Climbing fibers activate which cell layer of the cerebellum? |
inhibitory Purkinje fibers |
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4 inhibitory descending axons from the cerebellar cortex |
Purkinje, stellate, basket and Golgi cells |
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Why do cerebellar lesions result in ipsilateral deficits? |
the motor systems from cerebellum are double crossed |
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From where to climbing fibers arise? |
the contralateral inferior olivatory nulcues |
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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) |
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Stellate and basket cells |
narrow the spatial extent of excitatory inputs to Purkinje cells (enhanced signal resolution in the spatial domain) |
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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) |
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Are the deep cerebellar nuclei excitatory or inhibitory? |
excitatory |
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Lateral cerebellar lesions |
affect mainly distal limb coordination |
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Medial cerebellar lesions |
affect mainly trunk control, posture, balance, and gait |
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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 |
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Lesions in the cerebellar vermis |
Do not typically cause unilateral deficits because the medial motor systems influence proximal trunk mucles bilaterally |
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Deep nuclei of the lateral hemisphere |
Dentate nucleus |
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Cerebellar peduncle of the lateral hemisphere |
superior cerebellar peduncle |
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Output Targets of lateral hemispheres |
Ventrolateral nucleus of thalamus (VL), parvocellular red nucleus |
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Deep nuclei of intermediate hemipshere |
interposed nuclei (emboliform + globose) |
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Cerebellar peduncle of intermediate hemisphere |
superior cerebellar peduncle |
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Output target of intermediate hemisphere |
VL, magnocellular red nucleus |
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Deep nuclei of vermis |
Fastigial nucleus |
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Cerebellar peduncle of Vermis |
superior cerebellar peduncle, uncinate fasiculus, juxtarestiform body |
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Output targets of vermis |
reticular formation, vestibular nuclei |
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Deep nuclei of inferior vermis and flocculonodular lobe |
vestibular nuclei |
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Cerebellar peduncle of inferior vermis and flocculonodular lobe |
juxtarestiform body |
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Output targets of inferior vermis and flocculonodular lobe |
medial longitudinal fasiculus (eye movement pathways) |
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Output signals come from the motor cortex, to the cerebellar deep nuclei to what structure next? |
thalamus (VL), red nucleus or MLF |
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From the dentate nucleus, where does the output signal go next? |
thalamus (VL) |
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From the vestibular nucleus in the cerebellum, where does the output signal go next? |
MLF |
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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 |
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Reciprocal connections between the cerebellum and vestibular nuclei are important for what? |
equilibrium and balance |
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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 |
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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) |
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Pontine nuclei |
scattered areas of gray matter in the ventral pons interspersed among the descending corticospinal and corticobulbar tracts |
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The pontocerebellar fibers reach the cerebellum via _______ through the _______ cerebellar peduncle |
pontine nuclei; middle |
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4 spinocerebellar tracts |
Dorsal, ventral, rostral and cuneocerebellar tracts |
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A patient with damage to the cuneocerebellar tract will have decreased coordination in which part of the body? |
upper extremity |
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A patient with damage to the dorsal spinocerebellar tract will have decreased coordination in which part of the body? |
lower extremity |
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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 |
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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 |
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Main Origins of Input: Doral Spinocerebellar Tract |
leg proprioceptors |
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Main Origin of Input: Cuneocerebellar Tract |
Arm proptioceptors |
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Main Origin of Input: Ventral Spinocerebellar Tract |
Leg interneurons |
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Main Origin of Input: Rostral Spinocerebellar Tract |
Arm interneurons |
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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 |
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Cerebellar penduncle: Dorsal spinocerebellar tract |
inferior cerebellar peduncle |
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External cuneate nucleus |
located in the medulla, just lateral to the cuneate nucleus; site of cells for cuneocerebellar fibers |
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Cerebellar peduncle: Cuneocerebellar tract |
inferior cerebellar peduncle |
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The ventral spinocerebellar tract arises from ______ |
spinal border cells |
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Cerebellar peduncle: Ventral spinocerebellar tract |
superior cerebellar peduncle |
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Cerebellar peduncle: Rostral spinocerebellar tract |
superior and inferior cerebellar peduncle |
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Corticopontine fibers travel to (ipsilateral or contralateral) pons? |
ipsilateral |
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Pontocerebellar fibers travel from the pons to the (ipsilateral or contralateral) cerebellum? |
contralateral middle cerebellar peduncle |
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The nucleus Dorsalis of Clark sends sensory innervation to the cerebellum (inferior peduncle) via which tract? |
dorsal spinocerebellar, then become Mossy fibers |
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3 major arteries to the cerbellum |
PICA, SCA, AICA |
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The PICA usually arises from _______ |
the vertebral artery |
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The AICA usually arises from _______ |
the lower basilar artery |
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The SCA usually arises from _____ |
the top of the basilar artery, just below the posterior cerebral artery |
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The PICA supplies |
the lateral medulla, most of the inferior half of the cerebellum, and the inferior vermis |
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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 |
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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 |
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An infarct that involves just the cerebellum itself is most like in which cerebellar artery? |
SCA |
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Infarcts of the lateral pons or medulla that spare the cerebellum most often occur in which arteries? |
PICA and AICA |
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Large cerebellar infarcts in the PICA or SCA |
can cause swelling of the cerebellum --> hydrocephalus due to compression of 4th ventricle |
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Presentation of cerebellar hemorrhage |
headache, nausea, vomiting, vertigo, possible hydrocephalus + 6th nerve palsies and impaired consciousness |
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Fatal gastroenteritis |
cerebellar hemorrhage that initially presents with only GI symptoms of nausea and vomiting |
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Tx hydrocephalus due to hemorrage |
ventriculostomy; this carries risk of upward transtentorial herniation as the posterior fossa hemorrhage and edema expand |
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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 |
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dysrhythmia |
ataxic movments with abnormal times |
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dysmetria |
abnormal projections through space (over or undershooting) |
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Lesions confined to the ________ affect primarily the medial motor systems |
cerebellar vermis |
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Gait associated to vermis lesions |
wide-based, unsteady, "drunk-like"; Truncal ataxia |
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Ataxia associated with intermediate and lateral portions of cerebellum |
appendicular ataxia |
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Ataxia associated with unilateral lesion in the lateral portion of the cerebellum |
No appreciable deficit |
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Lesions of the cerebellar hemispheres cause (ipsilateral, contralateral, bilateral) symptoms in the extremities |
ipsilateral |
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Lesions of the cerebellar peduncles cause (ipsilateral, contralateral, bilateral) deficits |
ipsilateral |
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Cerebellar lesions affected the medial motor system cause (ipsilateral, contralateral, bilateral) |
bilateral (truncal ataxia) |
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What is ataxia-hemiparesis? |
ataxia along with motor loss; internal capsule lesions affect corticospinal tract and corticopontine fibers both; often caused by lacunar infarcts |
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In ataxia hemiparesis, the ataxia is usually (contralateral, ipsilateral) to the lesion and the hemiparesis is usually (contralateral, ipsilateral) to the lesion |
contralateral, contralateral |
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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) |
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Sensory Ataxia |
occurs when the posterior-column-medial lemniscal pathways is disrupted, resulting in loss of joint position sense |
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Sensory Ataxia is made worse by |
closing the eyes |
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Cause of Sensory Ataxia |
lesions of peripheral nerves or posterior column |
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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 |
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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 |
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The finger-to-nose test |
the patient touches their nose and then the examiner's finger alternately; tests for ataxia |
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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 |
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Tests for dysrhythmia |
Rapid tapping of fingers together, of the and on the thigh or of foot on the floor |
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Dysdiadochokinesia |
abnormalities of rapid alternating movements, such as alternately tapping one hand with the palm and dorsum of the other hand |
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Testing for overshoot |
have the pt raise both arms suddenly from their lap or lower them suddently to the level of the examiners hand |
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Postural tremor |
occurs when the limg muscles are activated to hold a particular position |
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Tandem gait |
the heel touches the toe with each each, forcing the patient to assume a narrow stance (tests truncal ataxia) |
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The Romberg test checks for (truncal or appendicular ataxia)? |
truncal |
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titubation |
tremor or the trunk or head associated with midline lesions |
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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 |
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Scanning or Explosive Speech |
Ataxic quality of speech with irregular fluctuations in rate and volume; associated with cerebellar disorders |
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A patient has inability to touch their finger to their nose. This is (truncal or appendicular ataxia)? |
appendicular ataxia |
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Most common causes of acute ataxia in adults |
toxin ingestion and ischemic or hemmoragic stroke |
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Common causes of chronic ataxia in adults |
cerebrovascular disease, brain metastases, chronic toxin exposure (medications, alcohol), MS, degenerative disorders of the cerebellum |
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Acute Ataxia in children |
accidental drug ingestion, varicella-associated cerebellitis, migraine |
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Chronic ataxia in children |
cerebellar astrocytoma, medulloblastoma, Friedreich's ataxia, ataxia-tenagiectasia |
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Hereditary Ataxia Syndromes |
sponocerebellar ataxia (SCA); gene defects encoding polyglutamine trinucleitide repeats |
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eye movement abnormaliities localize to ___ (2) of cerebellum |
vermis |
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2 lobes of cerebellum |
anterior |
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___ fissure is visible only on ventral surface of cerebellum |
posterolateral |
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posterolateral fissure separates ___ from ___ |
flocculonodular lobes |
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flocculus is medial/lateral to nodulus |
lateral |
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tonsillar herniation is bad because of ___ |
compression of medulla, compromising respiratory centers |
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superior cerebellar peduncle decussates at level of ___ |
inferior colliculi |
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middle cerebellar peduncle primarily carries ___ |
cerebellar inputs |
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inferior cerebellar peduncle primarily carries ___ |
cerebellar inputs |
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intermediate hemispheres do ___ |
appendicular coordination |
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vermis/flocculonodular lobes do ___ (2) |
axial coordination |
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deep cerebellar nuclei from lateral to medial |
dentate |
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___ comprise the interposed nuclei |
emboliform |
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___ is active before voluntary movements |
dentate |
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dentate nuclei receive inputs from ___ |
lateral cerebellar hemispheres |
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interposed nuclei receive inputs from ___ |
intermediate cerebellar hemispheres |
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fastigial nuclei receive inputs from ___ |
vermis |
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cerebellar cortex has ___ layers |
3 |
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3 layers of cerebellar cortex from deep to superficial |
granule cell layer |
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molecular layer contains ___ (3) |
granule cell axons |
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2 kinds of cerebellar input fiber types |
mossy fibers |
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mossy fibers synapse on ___s |
granule cells |
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granule cell axons give off ___s in the molecular layer |
parallel fibers |
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parallel fibers run in plane of ___ and perpendicular to ___, with which they synapse |
surface of folium |
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synapses from parallel fibers to purkinje cells are excitatory/inhibitory |
excitatory |
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purkinje cells synapse on ___s |
deep nuclei |
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synapses from purkinje cells on deep nuclei are excitatory/inhibitory |
inhibitory |
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climbing fibers start in ___ |
contralateral inferior olivary nucleus |
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climbing fibers grow along axon of ___ |
purkinje cell |
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climbing fibers synapse on approximately ___ purkinje cells |
10 |
|
synapse from climbing fiber on purkinje cell is excitatory/inhibitory |
excitatory |
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each purkinje cells receives synapses from ___ climbing fibers |
1 |
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3 kinds of cerebellar interneurons |
stellate |
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stellate cells are located in ___ layer |
molecular |
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basket fibers have dendrites oriented ___ly |
perpendicular to parallel fibers of molecular layer |
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golgi cells receive inputs from ___ |
parallel fibers of molecular layer |
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cerebellar glomeruli are located in ___ layer |
granule cell |
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cerebellar glomeruli have ___ (2) as inputs and ___ as terminus |
mossy fiber |
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on microscopy, cerebellar glomeruli look like ___s |
clearings among granule cells |
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lesions of ___ cerebellum cause ipsilateral deficit because of ___ |
lateral and intermediate |
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all cerebellar output pathways project to ___ (2) |
cortex |
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cerebellar outputs project to cortex through ___ |
contralateral VL pars caudalis of thalamus |
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VL projects to ___ (5) cortices |
motor |
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lateral and intermediate cerebellar output projects to medulla through ___ |
contralateral red nucleus |
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lateral cerebellar outputs all project through ___ |
dentate nucleus |
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lateral cerebellar outputs project from dentate nucleus to medulla through ___ |
parvocellular red nucleus |
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parvocellular red nucleus is the ___ part |
rostral |
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intermediate cerebellar outputs all project through ___ |
interposed nuclei |
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intermediate cerebellar outputs project to medulla through ___ |
magnocellular red nucleus |
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magnocellular red nucleus gives rise to ___ |
rubrospinal tract |
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parvocellular red nucleus projects to ___ in medulla via ___ |
inferior olivary nucleus |
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first neuron in triangle of Guillain-Mollaret has soma in ___ and projects to ___ |
lateral cerebellum |
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2nd neuron in triangle of Guillain-Mollaret has soma in ___ and projects vis ___ to ___ |
dentate nucleus |
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3rd neuron in triangle of Guillain-Mollaret has soma in ___ and projects via ___ to ___ |
parvocellular red nucleus |
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4th neuron in triangle of Guillain-Mollaret has soma in ___ and projects via ___ to ___ |
inferior olivary nucleus |
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triangle of Guillain-Mollaret is aka ___ |
myoclonic triangle |
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lesion of triangle of Guillain-Mollaret can cause ___ which presents with ___ |
hypertrophic olivary degeneration |
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T/F: projections from lateral and intermediate cerebellum go to distinct parts of VL |
TRUE |
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2 kinds of medial cerebellar outputs |
superior vermis |
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cerebellar outputs from superior vermis all project through ___ |
fastigial nuclei |
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cerebellar outputs from superior vermis project to ipsilateral medulla via ___ and contralateral medulla via ___ |
juxtarestiform body |
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superior vermis projects to ___ in ipsilateral medulla |
vestibular nuclei |
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superior vermis projects to ___ in contralateral medulla |
vestibular nuclei |
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juxtarestiform body is visible at ___ |
lateral wall of 4th ventricle |
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inferior cerebellum and flocculonodular lobe all project via ___ to ___ |
juxtarestiform body |
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T/F: no cerebellar outputs project to lower motor neurons |
false: some fastigial projection to upper C cord |
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all cerebellar inputs except those from ___ are via ___ |
inferior olivary nuclei |
|
cerebellar inputs from inferior olivary nucleus are carried via ___ |
climibing fibers |
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cortical inputs to cerebellum project first to ___ |
ipsilateral pontine nuclei |
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pontine nuclei project to contralateral cerebellum via ___ |
middle cerebellar peduncle |
|
spinal inputs to cerebellum travel via ___ |
spinocerebellar tracts |
|
4 spinocerebellar tracts |
dorsal 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 |
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soma of 1st neuron in dorsal SCT is in ___ |
leg DRG proprioceptor |
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nucleus dorsalis of clark is located at ___ (on axial slice) |
antero-medial aspect of posterior grey horn |
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soma of 2nd neuron in dorsal SCT is in ___ |
nucleus dorsalis of clark |
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in spinal cord, dorsal SCT runs in the ___ |
dorsolateral funiculus |
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soma of 1st neuron in cuneocerebellar tract is in ___ |
arm DRG proprioceptor |
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soma of 2nd neuron in cuneocerebellar tract is in ___ |
external nucleus cuneatus |
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soma of 1st neuron in ventral SCT tract is in ___ (2) |
spinal border cells |
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spinal border cells are located in ___ |
outer edge of central grey |
|
ventral SCT decussates at ___ |
AWC and after entering cerebellum via superior peduncle |
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anterior aspect of cerebellum is primarily perfused by ___ |
AICA |
|
posterior cerebellum is primarily perfused by ___ |
SCA and PICA |
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cerebellar infarcts occur primarily in ___ (2) territories |
SCA |
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cerebellar infarcts sparing the brainstem are primarily in ___ territory |
SCA |
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5 extra-cerebellar lesions which cause ataxia (or similar symptoms) |
pons |