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Neuro Midterm
Cerebellum Ppt
94
Anatomy
Professional
11/07/2011

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Term
What is ataxia?
Definition
Disordered contractions of agonist & antagonist muscles
Term
What is the term associated with ataxia (and most cerebellar disorders) that has to do with abnormal timing? with abnormal trajectories through space?
Definition
-dysrhythmia
-dysmetria
-abnormal overshoot
-abnormal undershoot
Term
Give an example of when ataxia occurs
Definition
Trauma, brain injury, contre coup (affects vision in occipital lobe of cerebrum), ischemiaļƒ  ataxia
Term
What constitutes the midline cerebellum and what are its fxns?
Definition
-archicerebellum and paleocerebellum
-truncal movements
Term
What constitutes the neocerebellum and what are its fxns?
Definition
-cerebellar hemispheres
-ipsilateral skilled movements (fine motor skills)
Term
What do lesions in the cerebellum cause? why?
Definition
ataxia in ipsilateral (to side of lesion) extremities.
-bc because cerebellar connections are either ipsilateral, or cross twice, between the cerebellum and the spinal cord
Term
Why is a cerebellar stroke quick to heal?
Definition
cerebellum has redundant (recurrent) circuitries, so is quick to heal and/ or relearn.
Term
What are the 3 I's of a cerebellar stroke?
Definition
-intact structure deprived of regulation (of motor and sensory tracts)
-ipsilateral
-improves with time
Term
What are some tests of ipsilateral skilled movements?
Definition
pill rolling tremor
natural activities with (jerky) tremor
finger to nose
heel-down-shin
knee pat (pronate -supinate)
foot pat
rebound
Term
what are some tests to test cerebellar vermis/lesion?
Definition
nystagmus
dysarthria
unsteadiness
gait
Term
What are 3 types of tremors observed in cerebellar digression?
Definition
-intention tremor
-cerebellar- when intention becomes more severe towards target
-Parkinsonian- rolling a pill
Term
What does the neocerebellum (more lateral cerebellum) present clinically? (with ischemia and hemorrhage)
Definition
incoordination (ataxia with movement of extremities)
cerebellar tremor
Term
What does the midline cerebellum present clinically? (with ischemia and hemorrhage)
Definition
truncal symptoms:
unsteadiness (gait)
nystagmus
dysarthria (scanning speech)
Term
What are arteries that supply the cerebellum? From what do they branch?
Definition
PICA (post. inferior cerebellar artery)
AICA (ant. inferior cerebellar artery)
SCA (superior cerebellar artery)

-all from the vertebro-bailar systems
-joins with vertebral vasculature to form the circle of willis.
Term
What does it mean if white areas present on an MRI/PET?
Definition
infarcted areas
Term
What are some causes of cerebellar hemorrhages? (uncommon and usually in smaller vessels)
Definition
-hypertension
-AVM
-hemorrhagic conversion of ischemic infarct
Term
Where do cerebro vascular issues come from?
Definition
thrombus and embolus from periphery (carotids)
-carotids enter brain first due to their early positioning on the aorta.
Term
How are cerebellar hemorrhages presented clinically?
Definition
Picture of increased intracranial pressure
Unsteadiness/ataxia
Hydrocephalus
Brainstem compression--> death
Term
How are cerebellar hemorrhages treated?
Definition
surgical evacuation
Term
in hydrocephalus, when there is a hamorrhage in the 4th ventricle, how does it get blocked?
Definition
due to small entrance hole to 4th ventricle, so CSF backs up in ventricles 1,2,3
Term
What is the most common cause of stroke?
Definition
hypertension
Term
Can TIA (temporary ischemia) occur in the cerebellum?
Definition
yes, but is more common in the cerebrum
Term
Can non-cerebellar ataxia occur? if so, how?
Definition
Yes.
In the form of sensory ataxia.
When posterior column-medial lemniscus pathway is interrupted--> get loss of position sense.
-overshoot limbs
-broad, unsteady gait
-usually caused by peripheral neuropathy
Term
How can sensory ataxia be improved?
Definition
by visual feedpack: Positive Romberg
Term
How can sensory ataxia be improved?
Definition
by visual feedpack: Positive Romberg
Term
What kind of connection do fine motor skills and balance and movement have?
Definition
reciprocal connection
Term
How many pathways are there to the cerebellum (afferent)? away (efferent)?
Definition
afferent=6
efferent=3
Term
What are some differential diagnoses of ataxia (non-cerebellar) for adults?
Definition
acute:
-toxic ingestion (alcohol)
-stroke

chronic?
-brain metastases
-chronic alcohol exposure
MS
Term
What are some differential diagnoses of ataxia (non-cerebellar) for children?
Definition
acute:
-accidental drug ingestion
-varicella (chix pox)- associated cerebellitis
-migraine

chronic:
-astrocytoma or medullablastoma
Term
How does alcohol affect the brainstem?
Definition
-hits brainstem first
-HR altered
-breathing altered
-gait altered
Term
What medicine do you give to heart failure pts? what does it do?
Definition
digitalis- makes heart contract more.
Term
What are the three cortexes surrounding the central sulcus?
Definition
-primary (motor) cortex (precentral)
-premotor cortex (precentral and lateral)
-primary (sensory) cortex (postcentral)
Term
Ischemic areas cannot be clearly defined.. what are the areas of ischemia?
Definition
umbra- dead
-surrounded by pen (part which is dying)
Term
A pt with Ca channel blocker has what side effects?
Definition
-lack of impulses (Ca triggers impulses)
-constipation
Term
What is the lateral sulcus/ lateral fissure/ sylvian fissure?
Definition
-fissure or deeper sulcus bw temporal and frontal lobe
Term
Whaich area on the sensory homunculous is notedly big?
Definition
lips, because comes from a wide sulcus on the postcentral sensory gyri.
Term
What is the connection bw inhibitory and excitatory NTs?
Definition
reciprochal
Term
Which NT can be inhibitory and excitatory, depending on the area?
Definition
L-Dopa
-too much, schizo
-too little, parkinsons
Term
What do gyri contribute to brain fxn?
Definition
give brain bigger surface area, so more sensory and motor areas can be covered.
Term
What do gyri contribute to brain fxn?
Definition
give brain bigger surface area, so more sensory and motor areas can be covered.
Term
What do gyri contribute to brain fxn?
Definition
give brain bigger surface area, so more sensory and motor areas can be covered.
Term
What is a big part of the motor homunculus?
Definition
vocalization
Term
What is vastesia?
Definition
pins and needles sensation
Term
What becomes of efferent motor impulses?
Definition
crosses over and goes to spinal cord to spinal nerves.
Term
What did GABA-pentine do to Dr. Alli?
Definition
gave him amnesia when he was on sterroids.
-also saw 4 wives.
Term
how do impulses cross over to and from the post and pre central cortex?
Definition
sENSORY cORTEX:
-Left hemisphere receives input from right side of body

Motor Cortex:
-Left hemisphere controls body's right side.
Term
Which hemisphere is Broca's and Wernicke's area located in?
Definition
left
Term
What are the top 3 killers in U.S.? What is the silent killer?
Definition
1-Heart Attack
2-Colorectal
3-Stroke

Silent: Hypertension
Term
what are the 3 main cerebral arteries?
Which do most strokes involve?
Definition
middle, anterior and posterior cerebral arteries
-middle (MCA)
Term
When would you administer adenosine into MCA?
Definition
-hypoxic baby after childbirth (more common at high altitudes)
-MI
-A-fib
Term
What are the 3 branches of the MCA?
Definition
superior, inferior and deep
See slide 16, from Neuro-midterm ppt
KNOW WHRE ALL CEREBRAL ARTERIES ARE TO COMPARE TO HOMUNCULUS
Term
What do the MCA deep branches supply? What 3 problems can be associated here?
Definition
-basal ganglia
-production of dopamine
-dopamine issues can occur: schizo, parkinon's and huntington's
Term
From inferior to superior, what are the sensory homunculi on the precentral (motor) cortex?
Definition
swallowing
tongue
jaw
lips (big)
face (big)
eyelid/ball
Brow
Neck
Thumb and fingers (big)
Hand (big)
wrist
elbow
shoulder
trunk
hip
knee
ankle
toes
Term
From inferior to superior, what are the sensory homunculi on the postcentral (sensory) cortex?
Definition
-introabdominal
-pharynx
-tongue
-teeth, gums, jaw
-lips (big) (upper lip bigger)
-face
-nose
-eye
-thumb and fingers (index is biggest)
-hand
-wrist
-forearm
-elbow
-arm
-shoulder
-head
-neck
-trunk
-hip
-leg
-feet (big)
-toes
-genitals
Term
WHat results in an infarct of the Left MCA?
Definition
Right hemiplegia, right hemianesthesia, right homonymous hemianopsia

Left gaze preference

Global aphasia
Term
WHat results in an infarct of the Right MCA?
Definition
Left hemiplegia, left hemianesthesia, left homonymous hemianopsia

Right gaze preference

Left hemineglect
Term
Which MCA area is affected most? why?
Definition
inferior MCA, bc of gravity
Term
What is the same word for ipsilateral?
Definition
homonymous
Term
what is aphasia
Definition
inability to talk
Term
What are the 3 types of aphasia (with lost repetition), and what area in the brain is the cause?
Definition
expressive (Broca's)- cannot express what he is thinking
-mostly nouns and verbs (telegraphic speech)
-often with right hemiparesis

receptive (Wernicke's)- cannot comprehend
-speech is fluent (but no meaning)
-unaware of deficit

conductive (lesion in area bw receptor and motor area)
-repetition affected
-reserved comprehension
Term
What are the two conditions of aphasia associated with preserved repetition?
Definition
isolation syndrome-
-destruction of zones bw ACA, MCA and PCA
-motor and receptive areas isolated from rest of the cortex of same hemisphere

partial isolation syndrome
Term
Where is Broca's located? Wernicke's?
Definition
-anterior to the central sulcus
-posterios to central sulcus
-have reiprochal relaitonship
Term
What happens when there is an infarct to the ACA?
Definition
sensory loss
weakness
Term
What are 2 basal ganglia?
Definition
putamen and globus pallidus
Term
What happens in a PCA infarct?
Definition
contralateral homonymous hemianopia
-if infarct is bilateral- cortical blindness
Term
Why is cortical blindness called cortical blindness?
Definition
bc involves occipital lobe.
Term
What is a watershed infarct and what are the most susceptible to?
Definition
Infarction of the cerebral cortex in an area of blood supply between two major cerebral arteries.

-ischemia
Term
How can watershed infarcts lead to systemic drop in BP?
Definition
When infarct is in 2 watershed zones:
bw ACA and MCA
bw MCA and PCA
Term
what is man-in-the-barrel syndrome?
Definition
-disproportionate weakness to both arms while everything else still works.
-due to bilateral supratentorial brain lesions caused by watershed infarcts
Term
What are some causes of man-in-the-barrel syndrome?
Definition
cerbral vascular disorders, cardiac and extracardiac surgeries, and pons and spinal cord involvement, bilateral brachial paralysis
Term
What is a Transient Ischemic Attack? (TIA)
Definition
Temporary narrowing of a vessel followed by return of flow before permanent damage occurs

-lasts less than 24 hours
Term
What are some causes of TIA?
Definition
-thrombus
-embolism- occluding vessel but then dissolving
-vasospasm
-cerebrovascular disease
Term
How do you tell if it was TIA or other transient neurological deficits?
Definition
-typical vascular pattern remains (MCA, ACA, PCA)
-but positive for stroke risk factors?
Term
What are some stroke risk factors?
Definition
Smoker
Hypertension
DM
Hypercholesterolemia
Heart disease, especially atrial fibrillation
Prior athersclerotic history
Positive family history
Term
What are some causes of transient loss of consciousness?
Definition
-basilar artery TIA
-seizure
-orthostasis
-cardiogenic syncope (due to vasovagal syncope or arrhytmia)
Term
STR-oke stands for what?
Definition
smile
tongue
raise arm
Term
What does a "stroke" refer to?
Definition
-hemorrhagic event
-ischemic infarction of brain
-can become hemorrhagic
Term
Uschemic strokes can be due to...
Definition
vasospasm
thrombis
embolus
Term
What are some sources of embolic infarcts?
good to know so future strokes may be prevented
Definition
-thrombotic material
-fat or cholesterol emboli from trauma to bones or arterial walls
-disc emboli in cervical trauma
-amniotic fluid emboli during childbirth
-contaminants in IV drugs
-air emboli in deep sea divers
Term
What are the 3 types od thrombotic emboli?
Definition
-Cardioembolic (A-fib, MI, lack of closure of patent foramen ovale, septic emboli)
-artery to artery
-dissection of carotid or vertebral leads to thrombus to embolus
Term
How does a patent foramen ovale cause thrombotic emboli?
Definition
venous thromboembolism is allowed to bypass lungs and go directly from right to left heart, and then to the brain.
Term
Where do large vessel infarcts occur?
Definition
MCA, ACA, PCA
Term
Where do small vessel infarcts occur
Definition
sometimes called lacunar infarcts (resemble small lakes)
-in deep vessels of basal ganglia, thalamus, internal capsule, medial portions of brainstem
Term
What is the cause of a lacunar infarct and what are they occluded by?
Definition
-hypertension
-liphyalinosis, atherosclerosis, thrombus, embolus
Term
What happens in this lacunar syndrome: ataxic hemiparesis?
Definition
damage to proprioceptive cerebellar circuitry
Term
What happens when a lacune is thalamic?
Definition
contralateral somatosensory deficits
Term
What happens in basal ganlion lacunae?
Definition
movement disorders
Term
Seizure occur in about __% of stroke pts.
Definition
15
Term
Carotid stenosis occurs where? what is this cause usually?
Definition
just after carotid bifurcation
-atherosclerosic disease
-thrombi formed here can embolize distally giving rise to TIA's and strokes of:
-MCA
-ACA
-opthalmic artery (with monocular vision loss)
Term
How do you find carotid stenosis?
Definition
listen for bruits (whooshing sound)
Term
How can occlusion of an ICA (internal carotid artery) be asymptomatic?
Definition
when pt has good collateral flow via
-Anterior and Posterior communicating arteries
(on either side of ICA)
Term
what is a carotid endarterectomy?
Definition
artheromatous material is shelled out from ICA
-stroke treatment
-not always permanent
Term
What can cause a tear in an intimal layer of carotid or vertebral arteries? what can this progress to?
Definition
trauma, cough, sneeze
-a flap protrudes into vessel lumen
-stenosis ensues
-thrombus formed - can embolize
Term
What is the treatment of thrombi or emboli?
Definition
anticoacgulants
examples: aspirin, warfarin.
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