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130 Cards in this Set
- Front
- Back
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Amygdala lesion (bilateral)
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Kluver-Bucy syndrome: Hyperorality, hypersexuality, disinhibited behavior; docility, hyperphagia, visual agnosia
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Frontal lobe
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Disinhibition and changes in concentration, orientation, and judgement (personality changes); reemergence of primitive reflexes
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Right parietal lobe
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Spatial neglect syndrome (agnosia of the contralateral world)
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Left parietal lobe
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Gerstmann syndrome- Agraphia, acalculia, finger agnosia, LR disorientation
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Reticular activating system (midbrain)
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Reduced level of arousal and wakefulness (coma)
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Mammillary bodies
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Wernicke-Korsakoff syndrome
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Cerebellar hemisphere
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Intention tremor, limb ataxia, fall towards the side of the lesion, dysmetria, delays in initiating and stopping movement
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Cerebellar vermis
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Truncal ataxia, dysarthria
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Subthalamic nucleus
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Contralateral hemiballismus
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Hippocampus
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Anterograde amnesia (cannot make new memories)
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PPRF (paramedian pontine reticular formation)
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Eyes look away from the lesion
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Frontal eye fields
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Eyes look toward the lesion
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Superior colliculi
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Paralysis of upward gaze (Parinaud syndrome)
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Arcuate fasciculus
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Poor repetition
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Broca's aphasia (inferior frontal gyrus)
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Poor vocal expression
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Wernicke's aphasia (superior temporal gyrus)
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Poor comprehension
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Anterior spinal artery = medial medullary syndrome
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Contralateral hemiparesis (corticospinal tract: lower extremities- UMN), medial lemniscus (decreased contralateral proprioception), ipsilateral paralysis of the hypoglossal nerve)
Note that pain and temperature sensation are preserved. Remember that the nucleus of CN XII is in the central medulla and that you "lick the lesion" |
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PICA = Wallenberg's syndrome/lateral medullary syndrome
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Pain and temperature loss on the CL body and IL face (trigeminal nucleus), ipsilateral dysphagia, hoarseness, decreased gag reflex, vertigo, diplopia, nystagmus, vomiting, ipsilateral Horner's (descending sympathetic fibers), ipsilateral ataxia (loss of ICP to the cerebellum)
-The nuclei of CN IX, X, XI are in the lateral medulla (remember XII is medal) so the symptoms are due to lesions of these. Note that proprioception (medial lemniscus) and motor functions are maintained |
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AICA = lateral inferior pontine syndrome
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Ipsilateral facial paralysis, ipsilateral facial pain and temperature, contralateral pain and temperature loss in body, ipsilateral loss of taste from anterior 2/3 of tongue, ipsilateral cochlear nucleus (hearing loss), vestibular (nystagmus), ipsilateral dystaxia (MCP, ICP),
Note: No CL body paralysis or loss of vibration and proprioception! Remember the nuclei for CN V, VII, VIII are in the lateral pons (VI is medial) |
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Posterior cerebral artery
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CL hemianopia with MACULAR SPARING. Supplies occipital cortex
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Middle cerebral artery
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CL face and arm paralysis and sensory loss, aphasia, left-sided neglect. Amaurosis fugax occurs here, CL inferior quadrantanopsia, homonymous hemianopsia
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Anterior cerebral artery
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Leg-foot motor and sensory loss
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Anterior communicating artery
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Most common site of circle of Willis aneurysm; visual field deficits (bitemporal hemianopsia)
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Posterior communicating artery
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Common area of aneurysm; CN III palsy (eye looks down and out)
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Lateral striate
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"arteries of stroke" pure motor hemiparesis; supply internal capsule and basal ganglia
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Watershed zones
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Between ACA/MCA, PCA/MCA. Damaged in severe hypotension
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Basilar artery
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"locked-in" syndrome. CN III intact usually
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Sturge-Weber Syndrome
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Port-wine stains (nevus flammeus) in the V1 opthalmic distribution, ipsilateral leptomeningeal angiomas, pheochromocytomas. Can cause glaucoma, seizures, hemiparesis, and MR.
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Tuberous sclerosis
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Hamartomas in the CNS, skin, and organs; CARDIAC RHABDOMYOMAS, RENAL ANGIOMYOLIPOMA, subependymal giant cell astrocytoma (candlestick dropping within the ventricles), MR, seizures, ash-leaf spots, sebaceous adeoma, shagreen patch; AD
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von Hippel-Lindau disease
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Cavernous hemangiomas in skin, mucosa, organs; bilateral renal cell carcinoma, hemangioblastoma in retina, brain stem, cerebellum, pheochromocytoma. AD mutation VHL gene on chromsome 5.
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Where are Meissner's corpuscles located and what do they mediate?
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In glabrous (hairless) skin. They are large myelinated fibers that mediate position sense, DYNAMIC fine touch (manipulation). Adapt QUICKLY
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Where are Pacinian corpuscles located and what do they mediate?
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They are located in DEEP skin layers, ligaments, and joints. They mediate vibration and pressure and are large, myelinated fibers.
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What are Merkel's disks and what do they mediate?
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Large, myelinated fibers that are located in superficial hair follicles and mediate position sense, STATIC touch (shapes, edges, textures). They adapt SLOWLY.
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What neurotransmitter is decreased in REM sleep?
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ACh (decreased in Huntingtons and Alzheimers)
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Where is GABA synthesized?
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Nucleus accumbens (decreased in anxiety and Huntingtons)
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Where is ACh synthesized?
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Basal nucleus of Meynert
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What does the supraoptic nucleus of the hypothalamus do?
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Makes ADH
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What does the paraventricular nucleus of the hypothalamus do?
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Makes oxytocin
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What does the lateral area of the hypothalamus do?
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Mediates hunger- destruction causes anorexia and FTT; INHIBITED by leptin
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What does the ventromedial area of the hypothalamus do?
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Mediate satiety- destruction causes hyperphagia (seen in craniopharyngioma). ACTIVATED by leptin
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What does the anterior hypothalamus do?
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Cooling, parasympathetic
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What does the posterior hypothalamus do?
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Heating, sympathetic
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What does the suprachiasmatic nucleus of the hypothalamus do?
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Circadian rhythm
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What nucleus of the thalamus mediates vision?
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LGN- From CN II
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What nucleus of the thalamus mediates hearing?
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MGN- from the superior olive and inferior colliculus of the pons
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What provides input to the cerebellum?
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Ipsilateral inferior cerebellar peduncle (proprioception) and contralateral middle cerebellar peduncle. These act through climbing and mossy fibers. Once they reach the cerebellar cortex, Purkinje fibers project to the deep nuclei.
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How does the cerebellum provide output to the cortex?
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Through the superior cerebellar peduncle.
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What are the deep nuclei of the cerebellum?
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Dentate, Emboliform, Globose, Fastigial (L to M)
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What does the lateral part of the cerebellum mediate?
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Cerebrocerebellum- Voluntary movement of extremities
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What does the medial part of the cerebellum mediate?
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Spinocerebellum (vermis + paravermal regions)- Mediate balance, truncal coordination, ataxia, propensity to fall TOWARD the lesion
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What part of the basal ganglia inhibits movement?
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Globus pallidus internus directly inhibits the thalamus.
The direct pathway INHIBITS the globus pallidus internus, thereby stimulating movement. D1 receptors activate the direct pathway. |
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What part of the basal ganglia facilitates movement?
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Globus pallidus externa (blocks the STN from stimulating the globus pallidus internus). The indirect pathway INHIBITS the GPe, thereby inhibiting movement.
D2 receptors block the indirect pathway. |
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What are Lewy bodies?
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Alpha-synuclein (intracellular inclusions)
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How can you get hemiballismus?
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Lacunar stroke in a patient with long-standing hypertension
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What causes neuronal death in Huntington's?
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NMDA-R binding and glutamate toxicity
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What is dystonia?
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Sustained, involuntary muscle contractions- writer's cramp, blepharospasm, spasmodic torticollis
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Recurrent laryngeal nerve injury
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-Results in loss of all laryngeal muscles EXCEPT the cricothyroid (remember in embryo that the cricothyroid comes from the 4th branchial arch and the others come from the 6th)
-Travels with the inferior thyroid artery and can be injured during surgery to the neck (thyroidectomy) |
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What do Charcot-Bouchard microaneurysms affect?
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Small vessels- In the basal ganglia, thalamus, pons, cerebellar hemispheres. These occur with chronic hypertension.
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What is the difference between berry aneurysms and Charcot-Bouchard aneurysms?
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Berry- Saccular; affect large vessels (most notably the bifurcation of the anterior communicating) and lead to hemorrhagic stroke/subarachnoid hemorrhage and terrible headache.
Charcot-Bouchard- Microaneurysms; Affect small vessels (typically lenticulostriate, which are branches of the MCA) and are due to chronic hypertension. Rupture leads to intracerebral hemorrhage/hemorrhagic stroke that causes sudden focal loss of sensation or paralysis. |
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What does the middle meningeal artery arise from?
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Maxillary artery
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What is a complication of epidural hematoma?
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Rapid expansion under systemic arterial pressure leading to transtentorial herniation and CN III palsy.
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Which type of hematoma crosses suture lines?
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Subdural
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Which type of hematoma crosses the falx and tentorium?
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Epidural
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What are causes of parenchymal hematoma?
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Hypertension (Charcot-Bouchard), amyloid angiopathy (lobar strokes all over the brain), DM, tumor. These usually occur in the basal ganglia and internal capsule.
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What are the most vulnerable areas to global ischemia?
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Hippocampus, cerebellum, watershed areas, neocortex
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What is the histologic timeline of ischemic brain disease?
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12-48 hours: Red neurons (cytoplasmic eosinophilia)
24-72 hours: Necrosis + neutrophils 3-5 days: Macrophages 1-2 weeks: Reactive gliosis (astrocytes) + vascular proliferation >2 weeks: Glial scar |
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What causes ischemic strokes due to thrombi and where do they typically occur?
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Atherosclerosis causes; Usually occurs at the bifurcation of the ICA, origin of the MCA, and vertebrobasilar system.
Form a cystic cavity with reactive gliosis. |
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Where do ischemic strokes due to emboli occur?
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The emboli can come from atrial fibrillation, carotid dissection, patent foramen ovale (DVT), endocarditis. They usually affect large arteries, with the MCA most commonly.
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What causes hemorrhagic stroke?
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Aneurysm rupture usually, secondary to ischemic stroke followed by reperfusion (the vessels are fragile)
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What is normal pressure hydrocephalus?
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There is NOT an increase in subarachnoid space volume, but expansion of the venticles leads to dementia, ataxia, and urinary incontinence.
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What is communicating hydrocephalus?
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Decreased CSF absorption by the arachnoid villi, leading to increased ICP, papillema, and herniation
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What is hydrocephalus ex vacuo?
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Occurs when the the brain atrophies so it appears like there is increased CSF. This is seen in Alzheimers, Picks disease, and advanced HIV. The triad seen in NPH is NOT present.
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How far does the subarachnoid space extend?
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To the lower border of S2
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What tracts are the legs lateral?
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Lateral corticospinal and spinothalamic (dorsal columns, legs are medial)
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Fine touch and proprioception pathway
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Sensory nerve ending ---> DRG ---> dorsal column ----> synapses at the ipsilateral nucleus gracilis/cuneatis -----> decussates in medulla to enter the contralateral medial lemniscus ----> synapses at the ipsilateral VPL ----> sensory cortex
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Pain and temperature tract
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Sensory nerve ending (A-delta, C) ----> DRG ----> enters spinal cord through Lissauer and ascends ipsilaterally about 2-3 levels ----> synapses in the ipsilateral gray matter (dorsal horn) ----> Decussates in anterior commissure and ascends in the CL spinothalamic tract----> synapses at the VPL ----> Sensory cortex
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Descending voluntary motor
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Cell body in primary motor cortex ----> descends ipsilaterally through the internal capsule and decussates at the pyramids in the medulla ---> descends contralaterally in the lateral corticospinal tract----> synapses in the anterior horn of the spinal cord ----> LMN leaves spinal cord ----> synapses at the NMJ
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What is clasp knife spasticity?
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Initial jerking to passive extension followed by sudden release of resistance- UMN
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What lesions are seen in poliomyelitis?
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Destruction of cells in the anterior horn- LMN only- Muscle weakness, atrophy, fasciculations, fibrillation, hyporeflexia.
Dx: LP shows lymphocytes, slight elevation in protein, and NO change in glucose (opposite of GBS which shows increased proteins with few cells) |
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What is Werdnig-Hoffman disease?
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Infantile SMA (AR- SM1 gene) that presents as a floppy baby with tongue fasciculations. Due to destruction of anterior horn and LMN involvement.
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What is seen in ALS?
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BOTH LMN and UMN lesions- anterior horn and corticospinal tract lesions in the spinal cord. NO sensory, cognitive, or oculomotor deficits. Presents as fasciculations and eventual atrophy (especially in the hands and forearms).
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What defect may be seen in ALS?
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Superoxide dismutatse 1
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What can be used to treat ALS?
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Riluzole- decreases Glutamate release
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What defect is seen in syringomyelia?
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Damage to the anterior commissure- This disrupts the 2nd order neuron of the spinothalamic tract so that there is bilateral loss of pain and temperature in a cape like distribution (usually seen in C8-T1). It can expand to affect other tracts - anterior horn to cause atrophy (usually hands; different from ALS though because there are sensory deficits)
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What is seen in vitamin B12, Friedrich's ataxia, and vitamin E deficiency?
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Loss of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts: Ataxic gait, hyperreflexia, impaired position and vibration sense bilaterally.
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What is the cause of death in Friedrich's ataxia?
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Hypertrophic cardiomyopathy
Defect in frataxin leads to mitochondrial impairment |
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What spinal cord deficit would you see with total occlusion of the anterior spinal artery?
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Supplies the ventral surface so lose everything BUT the dorsal columns and tract of Lissauer (supplied by the posterior spinal artery)
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What can cause Horner's syndrome?
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Lesion of the spinal cord above T1: Pancoast tumor, Brown-Sequard, late-stage syringomyelia
Also disruptions in the descending sympathetic fibers from the hypothalamus (AICA, PICA lesions) |
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What supplies sensory input to the posterior half of the skull (anterior is trigeminal- DUH)?
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C2
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What supplies sensory input to the neck?
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C3 (high turtleneck), C4 (low collar)
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What dermatome is at L1?
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Inguinal ligament
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What dermatome is at L4?
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Knee caps
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What level are the reflexes at?
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Biceps- C5, 6
Triceps- C7, 8 Patella- L3, 4 Achilles- S1, 2 |
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Where do germinomas occur and what do they cause?
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Precocious puberty and parinaud syndrome (due to lesion of the superior colliculi); arise in the pineal gland.
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What information is carried in the inferior colliculus?
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Auditory
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What innervates the stapedius muscle in the ear?
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CN VII
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What is carried in the nucleus solitarius?
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Taste, baroreceptors, gut distension (VII, IX, X)
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What is carried in the nucleus ambiguus?
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Motor innervation of the pharynx, larynx, and upper esophagus (IX, X, XI)
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What does the dorsal motor nucleus do?
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Sends autonomic (parasympathetic) fibers to the heart, lungs, and upper GI
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What would happen if you had a CN XII lesion?
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Tongue deviates toward the lesion
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What would happen if you had a CN V motor lesion?
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Jaw deviates toward the lesion (due to bilateral cortical input to the lateral pterygoid)
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What would
happen if you had a CN X lesion? |
Uvula deviates away from the lesion
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What would happen if you had a CN XI lesion?
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Weakness turning head to CL side and shoulder droops on IL side
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What is Bell's palsy?
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Complete destruction of the facial nucleus itself or the facial nerve. Results in ipsilateral facial paralysis with inability to close the eye on the involved side. Associated with AIDS, Lyme disease (bilateral), HSV, Sarcoidosis, Tumors, DM
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What is seen with near and far vision?
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Near- ciliary muscle contracts (lens convex)
Far- ciliary muscle relaxes (lens flattens) |
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What is the pathway of aqueous humor?
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Made in the ciliary body (ciliary process by beta stimulation) and travels between the angle of the lens and iris into the anterior chamber. It goes through the trabecular meshwork (absorbs aqueous humor) and is collected in the canal of Schlemm
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What conditions are associated with cataracts?
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Age, smoking, EtOH, sunlight, classic galactosemia, galactokinase deficiency, diabetes, trauma, infection
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What function of CN III is affected first by compression (PCA berry aneurysm, uncal herniation, etc)?
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Parasympathetic (pupil constriction) because these fibers lie on the outside of the nerve, where as the motor lies on the inside (affected by vascular disease such as DM- sorbitol)
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What causes an APD?
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Optic nerve damage
Retinal detachment |
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What causes left upper quadrantic anopia?
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Lesion to right temporal lobe- Meyer's loop loops around temporal horn of lateral ventricle
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What causes left lower quandrantic anopia?
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Lesion to right parietal lobe- Dorsal optic radiation through internal capsule
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What is a consequence of senile plaques seen in Alzheimers?
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Amyloid angiopathy- intracranial hemorrhage
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What are neurofibrillary tangles?
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Abnormally phosphorylated tau protein (insoluble cytoskeletal elements and correlate with degree of dementia) Seen in AD
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What are Pick bodies?
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Intracellular, aggregated tau protein
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What are senile plaques?
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HTP + beta-amyloid central core + neurites seen in AD
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What are periventricular plaques?
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Areas of oligodendrocyte loss and reactive gliosis seen in MS. They show axon demyelination, depletion of oligodendrocytes, accumulation of lipid-laden macrophages (phagocytose products of myelin breakdown), fibrillary astrocytosis (response to injury), and infiltration by lymphocytes/monocytes possibly
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What is albuminocytologic dissociation?
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Increased CSF with normal cell count seen in GBS
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What is a cluster headache?
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Unilateral repetitive brief headaches characterized by periorbital pain associated with IL lacrimation, rhinorrhea, Horner's syndrome; Tx: sumatriptan
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What is the cause of migraines?
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Irritation of CN V and release of substance P, CGRP, vasoactive peptides
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Glioblastoma multiforme
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-Cerebral hemispheres, can cross corpus callosum
-Pseudopalisading tumor cells with necrosis and hemorrhage, cystic degeneration grossly -GFAP -Heterogenously enhancing -45-70 peak age |
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Meningioma
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-Convexities of hemispheres
-Arises from arachnoid cells -Psammoma bodies -50-70, women, NF2 -Uniformly enhancing |
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Schwannoma
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-S100
-Cerebellopontine angle -Bilateral in NF2 |
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Oligodendroglioma
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-Rare
-Frontal lobes, looks nasty as hell -Fried egg with calcifications |
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Pilocytic astrocytoma
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-GFAP
-Usually in cerebellum -Rosenthal fibers: eosinophilic, corkscrew fibers -Cystic and solid grossly |
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Medulloblastoma
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-Highly malignant
-Vermis; can compress 4th ventricle to cause hydrocephalus -Homer Wright pseudorosettes, small blue cells -<16 -Radiosensitive |
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Ependymoma
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-<3
-4th ventricle- hydrocephalus -Poor prognosis -Perivascular rosettes, blepharoplasts (basal cilary bodies) near nucleus |
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Hemangioblastoma
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-Cerebellar
-EPO -vHL syndrome when found with retinal angiomas -Foamy cells and vascular |
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What is associated with uncal herniation?
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Occurs when the medial portion of the temporal lobe herniates through the tentorium cerebelli
1. Ipsilateral dilated pupil/ptosis (CN III) 2. Contralateral homonymous hemianopia- Compression of ipsilateral PCA 3. Ipsilateral paresis- compression of CL cerebral crus (false localizing sign) 4. Duret hemorrhage- Caudal displacement of brainstem causing paramedian artery rupture |
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Lacunar stroke
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Due to hypertensive changes in small arteries of basal ganglia and deep white matter- hyaline arteriolarsclerosis. These lead to pure motor, pure sensory, ataxia-hemiplegia syndrome, or dysarthria-clumsy hand syndrome.
There are small cavitary spaces called lacunas |
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Where is the area postrema and what does it do?
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It is at the dorsal surface of the medulla at the caudal end of the fourth ventricle and it is the CTZ- no BBB here
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