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77 Cards in this Set
- Front
- Back
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Control of posture depends on what?
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Reticulospinal and Vestibulospinal (extensor tone);
Rubrospinal and corticospinal (Flexor tone) |
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How does the cerebellum affect control of posture?
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It inhibits the lateral vestibular nucleus of vestibulospinal tract
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What is decerebrate rigidity?
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Lesion below red nucleus and above vestibular nucleus; only the lateral vestibulospinal tract and reticulospinal input to motoneurons to exert tonic extension.
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What is decorticate rigidity?
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Lesion above red nucleus so rubrospinal tract to flex arms and extensor tone paths are intact.
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What happens to decerebrate posturing when cerebellum is removed?
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It is enhanced because cerebellum usually inhibits the remaining lateral vestibular nucleus.
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What is the premotor cortex for?
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sequence and strategy of movement; Cortex 8 (frontal eye field is inf 8)
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What is the supplementary motor cortex for?
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#6 - coordination of arms and legs
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What would central Horner's be accompantied by?
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Wallenburg's - Lateral medullary syndrome
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What does ultrasonography allow?
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Measurement of blood flow VELOCITY
think of the velocity of ultra SOUND |
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What does nuclear medicine technique allow visualization of?
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cerebral perfusion
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What can measure blood flow, metabolic rate for oxygen, and glucose?
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Positron emission tomography
PET (oxygen EMISSIONS) |
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What is endarterectomy?
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surgery for carotid stenosis
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What are drugs that prevent brain infarct?
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aspirin and ticlopidine
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What drugs increase cerebral tolerance for ischemia?
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Ca channel blockers and excitatory amino acid antagonists.
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How long is ischemia OK for before widespred destruction?
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4 mins
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What are the two types of strokes and their prevalences?
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Infarction (85%), Hemorrhage (15%)
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What is the leading cause of large vessel infarcts?
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artherosclerosis which causes thrombosis at highly turbulant branch points.
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What is medullary syndrome of wallenbyrg?
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contralateral sensory loss
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What would midbrain ischemia show? pons occlusion?
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1) oculomotor signs and altered mental status
2) bilateral weakness and sensory loss |
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What is the major cause of small vessel occlusion?
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Chronic hypertension that causes lipid deposition
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What is the most common clinical feature of small vessel occlusion?
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Pure motor hemiparesis, NO SENSORY LOSS because it is most likely lacunar
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What areas of the brain do small vessel occlusions affect?
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deep structures such as IC, basal ganglia, pontine base
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What are the main areas for aneurysms?
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branching sites in the circle of willis
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What is acute stroke therapy?
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Acute AAT: antiplatelet, anticoagulant, thrombolytics
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What is TPA and what is it used for?
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Tissue plasminogen activator used as thrombolytic in acute stroke (less than 3 hrs)
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what are risk factors for stroke? The single greatest risk factor?
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Old Black Hypertensive Males:
Single biggest risk factor: HAVING A PREVIOUS STROKE |
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What is the neostriatum aka striatum?
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caudate + putamen
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What is the lentiform nucleus?
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Putamen + globus pallidus
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What is the corpus striatum?
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neostriatum + globus pallidus
(so caudate + putamen + globus pallidus) |
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What is the principal loop of basal ganglia?
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Cortex - striatum - globus pallidus - VaVl thalamus - cortex
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What are the two accessory loops of basal ganglia?
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subthalamus <--> globus pallidus
Substantia nigra <--> striatum |
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What are the H fields of forel?
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transitional zone between brainstem and brain (tegmentum and subthalamus)
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What fiber systems are involved with the prerubral fields (H fields of forel)?
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dorsolateral sensory fiber systems such as LST and trigem lemnisci
Medial and dorsomedial fiber such as MFB, mammillotegmental tract Subthalamic fiber systems to globus pallidus and VaVl thalamus |
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What is the direct pathway and what does it result in?
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Two GABAergic neurons in a row which reduces inhibition on thalamus = stimulation and hyperkinesia on cortex as in chorea
INCREASED CORTICAL ACTIVATION |
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What is the indirect pathway and what does it result in?
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Two GABAeric neurons in a row reduce inhibition of subthalamus which stimulates GABAergic neurons in the globus pallidus to inhibit VaVl thalamic nuclei = HYPOKINESIA as in parkinson.
DECREASED CORTICAL ACTIVATION |
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How does dopamine from substantia nigra affect the direct and indirect pathways?
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It stimulates direct and inhibits indirect pathways
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What does the cerebellum receive input from?
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Stretch receptors: muscle spindles and golgi tendon organs
visual/oculomotor |
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What does the cerebellum send motor output control to?
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Brainstem and cortex
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What is the cerebellum responsible for?
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coordination of movements (taxia)
unconscious proprioception |
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How many layers is the cerebellar cortex?
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Three: afferent, efferent, deep nuclei
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What is the flucculonodular lobe and what is it critical for?
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Its a little ninja that sits under the posterior cerebellar lobe that controls descending extensor systems involved with balance and posture.
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What is the somatotopy of the cerebellar cortical surface?
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Legs in anterior, then ARM and FACE then ARM then Leg again (like a palindrome)
Axial musculature in the midline |
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What does a hemispheric lesion to the cerebellum cause?
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ipsilateral ataxia
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What does lesion to the vermis cause?
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ataxia of the trunk and head (titubation)
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What can cause gait ataxia?
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alcohol effects on anterior lobe; continued use can cause permanent DRUNKEN ATAXIC GAIT
...but also SCA strokes and tumors :( |
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What does info does the spinocerebellar pathway carry? Which one come from the leg?
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Post/ant/cuneo/rostral spinocerebellar pathway gives bodily input to the cerebellum.
Posterior from legs |
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Medial cerebellar region:
What nucleus? What cerebellar cortex? What purpose? Output directed where? |
Fastigial nucleus by vermis and flocculonodular lobe for BALANCE AND POSTURE
to brainstem to affect extensor muscle tone (think: you want to balance so you extend your arms out) |
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What does posterior lobe of cerebellum coordinate?
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COODINATION of voluntary motor activity
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Purpose of anterior lobe of cerebellum?
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regulation of muscle tone
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What nucleus receives from the paravermal and hemispheric regions of the cerebellar cortex?
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Paravermal - interpositus
Hemisphere - dentate |
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Why are cerebellar lesions presented ipsilaterally?
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The dentatorubrothalamic tract crosses at the lower midbrain to control the contralateral motor cortex (which controls the initial ipsilateral side of the body)! COOL.
what a doublecrosser |
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All cells in the cerebellar cortex are what?
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INHIBITORY GABA CELLS except for granule cells
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What does the cerebellar inhibitory control system control?
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deep cerebellar nuclei output
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What are two big differences between basal ganglia and cerebellar lesions?
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Basal ganglia lesions produce motor disorders on the contralateral side and have RESTING tremors
Cerebellar lesions present ipsilaterally and have intention tremors |
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What is dysdiadochokinesis?
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inability to perform repetitive movements (cerebellar lesion)
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What is dysmetria?
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overshoot/undershoot of intended positions (cerebellar lesion)
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What are the characteristics of movement disorders?
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1) absence of motor weakness
2) involuntary movements 3) interrupted or poor coordination of volitional movements 4) abnormal posture and muscle tone |
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What is the cause of movement disorders?
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basal ganglia abnomalities
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What are the structures of basal ganglia?
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CPGSSS
caudate, putamen, globus pallidus, striatum, subthalamic nucleus, substantia nigra |
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What is the prototype disease with resting tremor?
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hypokinesia - Parkinson's
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What are the 4 signs of parkinson's
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Resting tremor, Akinesia/bradykinesia, Rigidity, Poor Balance
RAR, B! |
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What is damaged in a parkinson's patient?
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nigrostriatal pathway
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Treatment for parkinson's?
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L Dopa
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What are the hyperkinesias?
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Chorea, Dystonia, Myoclonus, Ballism
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What is geste antagoniste?
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A certain posture that makes dystonia twisting stop in a patient. ie touching face
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What causes Huntinton's Chorea?
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too much dopamine...
AD Chromosome 4 CAG repeat over 36 |
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What basal ganglia structure is messed in Huntington's?
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Striatal cells; loss of these cholinergic cells means dompaminergic system dominates
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What is the treatment for huntington's?
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dopaminergic blocker
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What is action exacerbated, treated with botulism or anticholinergics?
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Dystonia hyperkinesia; PUTAMEN is messed
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What are signs of huntington's?
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non-repetitive movements
AD dementia diffuse damage its like chorea plus dementia, SUCKS |
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What does damage of the left nigrostriatal pathway cause?
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Right hemi parkinism; remember that basal ganglia lesions are contralateral? yea, and cerebellar lesions present ipsilaterally
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What are postural tremors associated with?
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excess NE activity such as in hyperthroidism, amphetamine use
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What are end point exacerbation tremors usually caused by?
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Cerebellar damage as in MS; this will present IPSILATERALLY! yah.
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What NTs are involved with the basal ganglia?
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this summer: SAND and Grey Goose:
serotonin, ACh, NE, Dopamine, GABA, Glutamate |
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What is Myoclonus caused by?
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Decreased serotonin
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What kind of movement disorder is tourette's?What kind of people usually have this?
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Tics; ususally children with ADD or OCD
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What causes tics? Treatment?
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increased dopaminergic activity; treatments decrease NE activity or dopamine blockers
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