The notochord induces...
overlying ectoderm to differentiate into neuroectoderm and form the neural plate.
The neural plate gives rise to...
the neural tube and neural crest cells.
The notochord becomes...
nucleus pulposus of the intervertebral disc in adults.
The alar plate is...
The basal plate is...
During development, forebrain/prosencephalon includes...
the telencephalon and diencephalon.
Adult derivatives of the telencephalon are...
the cerebral hemispheres and the lateral ventricles.
Adult deriatives of the diencephalon are..
the thalamus and third ventricle.
During development the midbrain/mesencephalon includes...
Adult derivatives of the mesencephalon are...
the midbrain and aqueduct.
During development, the hindbrain/rhombencephalon includes..
the metencephalon and the myelencephalon.
Adult derivatives of the metencephalon are...
the pons, cerebellum and upper part of the 4th ventricle.
Adult derivatives of the myelencephalon are...
the medulla and lower part of the 4th ventricle.
Neuroectoderm derivatives (4)
1. CNS neurons 2. ependymal cells 3. oligodendroglia 4. astrocytes
Neural crest derivatives (2)
1. PNS neurons 2. Schwann cells
Mesoderm derivative (1)
Microglia (like Macrophages, derived from Mesoderm)
If neuroporses fail to fuse in the 4th week, there is....
persisten connection between the amniotic cavity and spinal canal. (neural tube defects)
Neural tube defects are associated with....
low folic acid intake before conception and during pregnancy.
Labs indicative of neural tube defects
-increased alpha-fetoprotein (AFP) -increased AChE in amniotic fluid
Spina bifida occulta is due to...
failure of the bony spinal canal to close but there is no structural herniation. The dura is intact.
Spina bifida occulta is associated with...
a tuft of hair or skin dimple at the level of bony defect. (usually lower vertebral levels)
Meninges (but not spinal cord) herniates through the spinal canal defect; normal AFP.
Meninges and spinal cord herniate through spinal canal defect.
malformation of the anterior neural tube resulting in no forebrain and an open calvarium ("frog-like" appearance).
Clinical findings of Anencephaly
increased AFP polyhydramnios (no swallowing center in brain)
Anencephaly is associated with...
maternal diabetes. Maternal folate supplementation decreases risk.
failure of the left and right hemispheres to separate usually during weeks 5-6.
Holoprosencephaly has a complex etiology that may be related to mutations in...
sonic hedgehog signaling pathway.
Moderate form of holoprosencephaly has...
cleft lip/palate and more severe form results in cyclopia.
Chiari II (Arnold-Chiari malformation) is...
significant herniation of cerebellar tonsils and vermis through the foramen magnum with aqueductal stenosis and hydrocephalus.
Chiari II often presents with...
lumbosacral myelomeningocele and paralysis below the defect.
agenesis of the cerebellar vermis with cystic enlargement of the 4th ventricle.
Dandy-Walker is associated with...
hydrocephalus and spina bifida.
Syringomyelia is a...
cystic cavity within the spinal cord that typically damages the crossing anterior spinal commissural fibers.
Syringomyelia presents with a...
"cape-like" bilateral loss of pain and temperature sensation in the upper extremities.
Syringomyelia is most common at...
Syringomyelia is associated with...
Chiari I malformation (> 3-5 mm cerebellar tonsillar ectopia; congenital and manifests with HAs and cerebellar symptoms)
The anterior 2/3 of the tongue are formed by...
1st and 2nd branchial arches (thus sensation via CN V3 and taste via CNVII).
The posterior 1/3 of the tongue is formed by...
the 3rd and 4th branchial arches (thus sensation and taste mainly from CN IX)
Motor innervation to the tongue is via...
Muscles of the tongue are derived from...
permanent cells; they do not divide in adulthood and generally do not have a progenitor stem cell population.
Cell bodies and dendrites of axons can be stained via...
Nissl substance (stains RER). RER is not present in the axon.
If an axon is injured, it undergoes...
Wallerian degeneration which is degeneration distal to the injury and axonal retraction proximally; this allows for potential regeneration.
Astrocyte Functions (6)
-physical support -repair -K+ metabolism -removal of excess NT -component of BBB -glycogen fuel reserve buffer
In response to neural injury, astrocytes cause...
-CNS phagocytes (scavenger cells) -not readily discernible in Nissly stains -small, irregular nuclei and little cytoplasm
Microglia respond to tissue damage by...
differentiating into large phagocytic cells.
HIV-infected microglia will...
fuse to form multinucleated giant cells in the CNS.
Myelin in the CNS is formed by...
oligodendrocytes. And by Schwann cells in the PNS.
Myelin increases both...
space constant and conduction velocity.
Each oligodendrocyte can....
myelinate many axons. It is the predominant glial cell in white matter.
On H&E, oligodendroglia have a..
"fried egg" appearance.
Oligodendroglia are injured in...
MS, progressive multifocal leukoencephalopathy (PML) and leukodystrophies.
Each Schwann cell myelinates...
only 1 PNS axon and they promote axonal regeneration.
Scwhann cells are destroyed in...
Acoustic neuroma is a...
type of schwannoma typically located in the internal acoustic meaturs (CN VIII).
If acoustic neuroma is bilateral, it is strongly associated with...
neurofibromatosis type 2.
Freen nerve endings description
C fibers - slow, unmyelinated Adelta fibers - fast, myelinated
Free nerve endings are located in the...
Free nerve endings sense...
pain and temperature.
Meissner corpuscles are..
large, myelinated fibers that adapt quickly.
Meissner corpuscles are located in...
glabrous (hairless) skin.
Meissner corpuscles sense...
dynamic, fine/light touch; position sense
Pacinian corpuscles are...
large, myelinated fibers that adapt quickly
Pacinian corpuscles are in the...
deep skin layers, ligaments and joints.
Pacinian corpuscles sens..
vibration and pressure.
Merkel discs are...
large, myelinated fibers that adapt slowly.
Merkel discs are located in..
the basal epidermal layer and hair follicles.
Merkel discs sense...
pressure, deep static touch; position sense
The endoneurim surrounds...
a single nerve fiber layers. This is the inflammatory infiltrate in Guillain barre.
The perineurium surrounds...
a fascicle of nerve fibers; must be rejoined in microsurgery for limb reattachment; permeability barrier.
The epineurium is a...
dense CT that surrounds the entire nerve (fascicles and blood vessels).
NE is synthesized in...
the locus ceruleus (pons).
Dopamine is synthesized in...
the ventral tegmentum and SNc (midbrain).
5-HT is synthesized in...
the raphe nucleus (pons, medulla, midbrain)
ACh is synthesized in...
the basal nucleus of Myenert.
GABA is synthesized in...
the nucleus accumbens.
NE change in disease (2)
increased in anxiety decreased in depression
Dopamin change in disease (3)
increased in Huntington decreased in Parkinson decreased in depression
Serotonin change in disease (3)
increased in Parkinson decreased in anxiety decreased in depression
ACh change in disease (3)
increased in Parkinson decreased in Alzheimer decreased in Huntington
GABA change in disease (2)
decreased in anxiety decreased in Huntington
The BBB is formed by 3 structures:
1. tight junctions between nonfenestrated capillary endothelial cells 2. basement membrane 3. astrocyte foot processes
Glucose and amino acids cross the BBB via...
slow, carrier-mediated transport.
Nonpolar/lipid-soluble substances cross the BBB via...
Areas of the brain w/o BBB allow for special brain functioning (3):
1. area postrema (vomiting after chemo) 2. OVLT (osmotic sensing) 3. neurohypophysis (ADH release)
In regards to the BBB, infarction or neoplasm can destroy...
endothelial cell tight junctions leading to vasogenic edema.
Functions of the Hypothalamus (7)
TAN HATS 1. Thirst and water balance 2. Adenohypophysis control 3. Neurohypophysis regulates hormones produced in the hypothalamus 4. Hunger 5. Autonomic regulation 6. Temperature regulation 7. Sexual urges
ADH is made in the...
Oxytocin is made in the...
ADH and oxytocin are both made by...
the hypothalamus but stored and released by the posterior pituitary.
Lateral area of the Hypothalamus
Hunger (destruction leads to anorexia and FTT) inhibited by leptin
Ventromedial area of the hypothalamus
Satiety (destruction leads to hyperphagia) stimulated by letin
Circadian rhythm controls the nocturnal release of...
ACTH, prolactin, melatonin, and NE.
The SCN releases...
NE to the pineal gland which releases melatonin.
SCN is regulated by...
the environment (light).
Extraocular movements during REM sleep are due to...
activity of PPRF (paramedian pontine reticular formation).
Alcohol, benzodiazapenines, and barbituates are associated with...
decreased REM sleep and delta wave sleep.
Bedwetting should be treated with...
oral desmopressin (DDAVP) which mimics ADH.
Treat night terrors and sleepwalking with...
Awake (eyes open) EEG
beta waves (high frequency, low amplitude)
Awake (eyes closed) EEG
Stage 1 NREM is...
light sleep with theta waves.
Stage 2 NREM is...
deeper sleep with sleep spindles and K complexes that makes up 45% of sleep.
Bruxism occurs during...
Stage 2 sleep.
Stage 3 NREM is...
deepest slow-wave sleep with delta waves (low frequency, high amplitude).
Sleepwalking, night terrors and bedwetting occur during...
stage 3 sleep.
REM sleep features
-loss of motor tone -increased brain O2 use -increased pulse/bp -memory processing function? -Beta waves
Dreaming and clitoral/penile tumescence occurs during...
The posterior pituitary (neurohypophysis) receives...
hypothalamic axonal projections from supraoptic (ADH) and paraventricular (oxytocin) nuclei.
The thalamus is the major relay for...
all ascending sensory info except olfaction.
spinothalamic and dorsal columns/medial lemniscus
pain/temp, pressure, touch, vibration and proprioception
primary somatosensory cortex
trigeminal and gustatory pathway
face sensation and taste
primary somatosensory cortex
superior olive and inferior colliculus of tectum
auditory cortex of the temporal lobe
basal ganglia and cerebellum
1. contralateral cortex via middle cerebellar peduncle 2. ipsilateral proprioceptive info via inferior cerebellar peduncle from the spinal cord
Cerebellum outputs information to the contralateral cortex to...
modulate movement. It starts at the purkinje cells then to the deep nuclei then to the contralateral cortex via the superior cerebellar peduncle.
Deep nuclei (from lateral to medial)
Dentate, Emboliform, Globose, Fastigial
Lateral lesions of the cerebellum affect...
voluntary movement of the extremities; when injured, there is a propensity to fall toward the injured side
Medial lesions of the cerebellum involve...
vermal cortex, fastigial nuclei and flocculonodular lobe resulting intruncal ataxia, nystagmus and head tilting.
Pts with medial lesions of the cerebellum may present with...
a wide-based gait and deficits in truncal coordination.
The basal ganglia is important in...
voluntary movements and making postural adjustments.
Basal ganglia receives...
cortical input and provides negative feedback to the cortex to modulate movement.
The exicatory pathway receives cortical inputs that...
stimulate the striatum to release GABA which disinhibits the thalamus via the GPi/SNr (leading to increased motion).
The inhibitory pathway receives cortion inputs that..
stimulate the striatum which disinhibits STN via GPe and then STN stimulates GPi/SNr to inhibit the thalamus (decreased motion).
In the excitatory pathway, dopamine binds to...
D1 stimulating the excitatory pathway. (increases motion)
In the inhibitory pathway, dopamine binds to...
D2 inhibiting the inhibitory pathway (increased motion).
Parkinson is a degenerative disorder of the CNS associated with...
Lewy bodies and loss of dopaminergic neurons in the substantia nigra pars compacta.
Lewy bodies are composed of..
alpha-synuclein - intracellular eosinophilic inclusions.
Clinical findings of Parkinson (5)
1. tremor (pill-rolling) 2. cogwheel rigidity 3. Akinesia 4. postural instability 5. shuffling gait
Huntington Disease features
-autosomal dominant -trinucleotide repeat of CAG on chr 4 -20-50 yrs old
Huntington is characterized by...
choreiform movements, aggression, depression and dementia.
Huntington pathology is due to...
decreased levels of ACh and GABA in the caudate. (atrophy of caudate on imaging)
In Huntington, neuronal death is via...
NMDA-R binding and glutamate toxicity.
sudden, wild flailing of 1 arm +/- ipsilateral leg
Characteristic lesion of hemiballismus
contralateral subthalamic nucleus (ex. lacunar stroke)
sudden, jerky, purposeless movements
Characteristic lesion of chorea and athetosis
slow, writhing movements (esp in fingers)
Myoclonus (sudden, brief, uncotrolled muscle contraction) is common in...
metaboic abnormalities such as renal and liver failure.
sustained, involuntary muscle contractions. Ex. writer's cramp, blepharospasm
Essential tremor (postural tremor) is an..
action tremor; exacerbated by holding posture/limb position
Treatment for essential tremor
Resting tremor is an...
uncontrolled movement of distal appendages; tremor is alleviated by intentional movement
Intetion tremor is a...
slow, zigzag motion when pointing/extending toward a target.
Characteristic lesion of intention tremor...
Lesion to the bilateral amygdala causes...
Kluver-Bucy syndrome (hyperorality, hypersexuality, disinhibited behavior); associated with HSV-1.
Lesions to the frontal lobe cause...
disinhibition and deficits in concentration, orientation and judgement; may have reemergence of primitive reflexes.
Lesions to the right parietal-temporal cortex cause...
spatial neglect syndrome (agnosia of the contralateral side of the world)
Lesions to the left parietal-temporal cortex cause...
agraphia, acalculia, finger agnosia and left-right diorientation (aka Gerstmann syndrome)
Lesion to the reticular activating system (midbrain) causes...
reduced levels of arousal and wakefulness
Lesion to the mamillary bodies causes...
Wernicke-Korsakoff syndrome (confusion, ophthalmoplegia, ataxia, memory loss, confabulation and personality changes.
Mamillary body lesions are associated with...
thiamine deficiency and excessive EtOH use; can be precipitated by giving glucose w/o B1 to a B1 deficient pt.
Basal ganglia lesion may result in...
tremor at rest, chorea or athetosis.
Cerebellar hemisphere lesions lead to..
intention tremor, ataxia and loss of balance
Cerebellar vermis lesions lead to...
truncal ataxia and dysarthria.
Lesions in the subthalamic nucleus lead to...
Lesions to the hippocampus cause..
Lesions to the paramedian pontine reticular formation lead to...
eyes looking away from the side of the lesion.
Lesions to the frontal eye fields lead to...
eyes looking toward the lesion.
Central pontine myelinolysis causes...
acute paralysis, dysarthria, dysphagia, diploplia and loss of consiousness. Can cause "locked-in syndrome".
Central pontine myelinolysis pathology is due to...
massive axonal demyelination in pontine white matter tracts secondary to osmotic forces and edema.
Central pontine myelinolysis is commonly iatrogenic caused by...
overly rapid correction of hyponatremia.
nonfluent aphasia with intact comprehension
Broca's area is located in the...
inferior frontal gyrus of the frontal lobe.
Wernicke's aphasia is...
fluent aphasia with impaired comprehension and repetition.
Wernicke's area is located in the...
superior temporal gyrus of the temporal lobe.
Global aphasia is...
nonfluent aphasia with impaired comprehension; both broca and wernicke areas are affected.
poor repetition but fluent speech; intact comprehension
Conduction aphasia can be caused by damage to..
left superior temporal lobe and/or left supramarginal gyrus.
Transcortical motor aphasia
nonfluent aphasia with good comprehension and repetition
Transcortical sensory aphasia
poor comprehension with fluent speech and repetition
Mixed transcortical aphasia
nonfluent speech, poor comprehension, and good repetition
Watershed zones of the brain are damaged in severe...
hypotension leading to upper leg/arm weakness and defects in higher-order visual processing.
Cerebral perfusion is primarily driven by...
PCO2 (PO2 can help in severe hypoxia).
Therapeutic hyperventilation (decreases PCO2) helps to decrease...
intracranial pressure in cases of acute cerebral edema via decreased cerebral perfusion by vasoconstriction.
If there is a lesion in the MCA supply to the motor cortex, this causes...
contralateral paralysis of the upper limb and face.
If there is a lesion in the MCA supply to the sensory cortex, this causes....
contralateral sensation of the upper and lower limbs and face.
If there is a lesion in the MCA supply to Wernicke's or Broca's area regions, this causes...
aphasia if in the dominant hemisphere (usually left) and hemineglect if it affects the nondominant side.
If there is a lesion in the ACA supply to the motor cortex, this causes...
contralateral paralysis in the lower limb.
If there is a lesion in the ACA supply to the sensory cortex, this causes...
contralateral loss of sensation in the lower limb.
If there is a lesion in the lenticulostriate artery to the striatum and internal capsule, this causes...
A lesion in the ASA to the lateral corticospinal tract will cause...
contralateral hemiparesis (arms and legs).
A lesion of the ASA to the medial lemniscus will cause...
decreased contralateral proprioception.
A lesion of the ASA to the caudal medulla will cause...
ipsilateral hypoglossal dysfunction (causing the tongue to deviate ipsilaterally).
Medial Medullary syndrome is caused by...
infarct of paramedian branches of ASA and vertebral arteries.
A lesion to the PICA will affect the...
lateral medulla (vestibular nuclei, lateral spinothalamic tract, spinal trigeminal nucleus, nucleus ambiguus, sympathetic fibers, and inferior cerebellar peduncle).
Symptoms of a PICA lesion include...
vomiting, vertigo, nystagmus decreased pain and temp sensation from ipsilateral face and contralateral body dysphagia hoarseness decreased gag reflex ipsilateral Horner ataxia dysmetria (Lateral Medullary Syndrome - Wallenberg)
AICA lesion affects the...
lateral pons (cranial nerve nuclei, vestibular nuclei, facial nucleus, spinal trigeminal nucleus, cochlear nuclei, sympathetic fibers). (Lateral Pontine Syndrome)
AICA lesion affecting the lateral pons causes...
vomiting, vertigo, nystagmus paralysis of the face decreased lacrimation and salivation decreased taste from 2/3 anterior tongue decreased corneal reflex decreased pain/temp in face ipsilateral decreased hearing and Horner
AICA lesions can also affect the middle and inferior cerebellar peduncles leading to...
ataxia and dysmetria.
PCA lesion affects the...
occipital cortex and visual cortex causing contralateral hemianopia with macular sparing.
Lesion to the basilar artery affects...
the pons, medulla, lower midbrain, corticospinal and corticobulbar tracts, ocular crainal nerve nuclei, and PPRF.
Basilar artery lesion causes...
"locked in syndrome": quadriplegia, loss of voluntary facial, mouth and tongue movements. (preserved consciousness and blinking)
Most common lesion of the anterior communicating artery is...
an aneurysm which can lead to visual field defects and stroke.
Saccular aneurysms can cause...
cranial nerve impingment.
The posterior communicating artery is a common location of...
saccular aneurysms where they cause CNIII palsy (pupil is down/out with ptosis and dilation).
abnormal dilation of the artery due to weakening of the vessel wall.
Berry aneurysms occur at...
the birfucations of the circle of willis, most commonly the junction of the ACA and anterior communicting a.
Rupture of berry aneurysms leads to...
subarachnoid hemorrhage (worst HA of life) or hemorrhagic stroke. Can also cause
Berry aneurysms can also cause bitemporal hemianopia due to..
compression of the optic chiasm.
Berry aneurysms are associated with...
ADPKD Ehlers-Danos Marfan
Risk factors of Berry aneurysms include...
advanced age HTN smoking race (AA)
Charcot-Bouchard microaneurysms are associated with..
chronic HTN and they affect small vessels (in basal ganglia, thalamus).
Central post-stroke pain syndrome is...
neuropathic pain due to thalamic lesions. Initial sense of numbness and tingling followed by allodynia and dysaesthesia.
Epidural hematoma is ususally due to..
rupture of the middle meningeal artery secondary to fracture of the temporal bone.
Rapid expansion is seen in epidural hematoma leading to...
transtentorial herniation and CN III palsy.
CT of an epidural hematoma shows...
convex (lentiform), hyperdense blood collection.
Epidural hematoma does not cross...
suture lines. It can cross falx and tentorium.
Subdural hematomas are usually due to...
rupture of bridging veins casuing slow venous bleeding.
Subdural hematomas are seen in...
elderly individuals, alcoholics, blunt trauma, shaken baby.
CT of a subdural hematoma shows...
crescent-shaped hemorrhage that crosses suture lines. Cannot cross falx, tentorium.
Time course of a subarachnoid hemorrhage is...
rapid and pts complain of worst HA of life. Due to rupture of aneurysm.
Spinal tap of subarachnoid hemorrhage shows...
bloody or yellow (xanthochromic) spinal tap.
2-3 days after a subarachnoid hemorrhage, there is risk of..
vasospasm due to blood breakdown (not visible on CT, treat with nimodipine) and rebleed (visible on CT).
Intraparenchymal (hypertensive) hemorrhage is most commonly caused by...
systemic HTN. Also seen with amyloid angiopathy, vasculitis and neoplasm.
Intraprenchymal hemorrhages typically occur in...
basal ganglia and internal capusle but can be lobar.
Irreversible damage from stroke begins after...
5 minutes of hypoxia.
Most vulnerable brain regions to stroke (ischemia) are:
-hippocampus -neocortex -cerebellum -watershed areas
Histology 12-48 hrs after ischemic event
Histology 24-72 hrs after ischemic event
necrosis + neurtrophils
Histology 3-5 days after ischemic event
Histology 1-2 wks after ischemic event
reactive gliosis + vascular proliferation
Histology more than 2 weeks after ischemic event
Hemorrhagic strokes are...
intracerebral bleeds often due to HTN, anticoagulation and cancer. May be secondary to ischemic stroke followed by reperfusion.
Most common site of hemorrhagic stroke
Ischemic stroke is...
acute blockage of vessels leading to disruption of blood flow and subsequent ischemia resulting in liquefactive necrosis.
3 types of ischemic stroke:
1. thrombotic 2. embolic 3. hypoxic
Thrombotic stroke is typically due to...
a clot forming directly at the site of infarction (commonly MCA), usually over an atherosclerotic plaque.
Embolic stroke is due to...
an embolus from another part of the body that obstructs a vessel; can affect multiple vascular territories.
Hypoxic stroke is due to..
hypoperfusion or hypoxemia. Common during CV surgeries; tends to affect watershed areas.
Treatment for ischemic stroke
tPA if within 3-4 hours of onset and no risk of hemorrhage.
Ischemic stroke risk can be decreased with...
aspirin or clopidogrel, bp control, and control of sugars and lipids.
A transient ischemic attack (TIA) is...
a brief, reversible episode of focal neurologic dysfunction lasting
The dural venous sinsues drain blood from...
cerebral veins and empty into the internal jugular vein. They receive CSF from arachnoid granulations.
The lateral ventricle empties to the...
3rd ventricle via the interventricular foramina of Monro.
The 3rd ventricle empties to the...
4th ventricle via the cerebral aqueduct.
The 4th ventricle empties to the...
subarachnoid space via the foramina of Luschka (Laterally) and the foramen of Magendie (medially).
CSF is made by...
ependymal cells of choroid plexus. It is reabsorbed by arachnoid granulations and then drains into dural venous sinuses.
A communicating hydrocephalus is due to...
decreased CSF absorption by the arachnoid granulations which can lead to increased intracranial pressure, papilledema and herniation. (ex. from arahnoid scarring post-meningitis)
Normal pressure hydrocephalus does not result in...
increased subarachnoid volume.
Normal pressure hydrocephalus is due to expansion of the...
ventricles that distorts the fibers of the corona radiata and leads to clinical triad of urinary incontinence, ataxia and cognitive dysfunction.
Hydrocephalus ex vacuo has the appearance of...
increased CSF that is actually the result of decreased neural tissue due to atrophy. Intracranial pressure is normal. Seen in Alzheimer, advanced HIV and Pick disease.
A noncommunicating hydrocephalus is caused by...
a structural blockage of CSF circulation within the ventricular system (ex. stenosis of the cerebral aqueduct).
There are 31 spinal nerves:
8 cervical 12 thoracic 5 lumbar 5 saccral 1 coccygeal
Nerves C1-C7 exit...
above their corresponding vertebra and all other nerves exit below. Ex. C3 exits above the 3rd cervical vertebra and L2 exits below the 2nd lumbar vertebra.
Vertebral disc herniation
nucleus pulposus herniates through the annulus fibrosus; usually occurs posterolaterally at L4-L5 or L5-S1
The spinal cord extends to...
the lower border of L1-L2 vertebrae.
The subarachonid space (contains CSF) extends to...
lower border of S2 vertebra so lumbar puncture is usually performed between L3-L4 or L4-L5 (level of cauda equina).
In the spinal cord, the legs are...
lumbosacral and lateral in the lateral corticospinal tract and spinothalamic tract.
The dorsal column is for...
ascending pressure, vibration, fine touch and proprioception.
1st order neuron of the dorsal column
sensory nerve ending leads to the cell body in the DRG which enters the spinal cord and ascends ipsilaterally in the dorsal column
1st synapse of the dorsal column
ipsilateral nucleus cuneatus or gracilis in the medulla
2nd order neuron of the dorsal column
decussates in the medulla and ascends contralaterally in the medial lemniscus
Synapse 2 of the dorsal column
VPL of the thalamus
3rd order neuron of the dorsal column
Spinothalamic tract function
-ascending -lateral: pain/temp -anterior: crude touch/pressure
1st order neuron of the spinothalamic tract
sensory nerve ending has cell body in DRG and enters spinal cord
Synapse 1 of spinothalamic tract
ipsilateral gray matter in spinal cord
2nd order neuron of the spinothalamic tract
decussates at the anterior white commissure and then ascends contralaterally
Synapse 2 of the spinothalamic tract
3rd order neuron of the spinothalamic tract
Lateral corticospinal tract fxn
descending: voluntary movement of contralateral limbs
1st order neuron of the corticospinal tract
UMN: cell body in primary motor cortex that descends ipsilaterally (through internal capsule), and most fibers decussate at the caudal medulla (pyramidal decussation) and then descend contralaterally
Synapse 1 of the lateral corticospinal tract
cell body of the anterior horn
2nd order neuron of the lateral corticospinal tract
LMN: leaves spinal cord
synapse 2 of the lateral corticospinal tract
+ UMN lesion + LMN lesion
- UMN lesion +LMN lesion
- UMN lesion + LMN lesion
increased UMN lesion decreased LMN lesion
increased UMN lesion decreased LMN lesion
+ UMN lesion - LMN lesion
Spastic paralysis sign
+ UMN lesion - LMN lesion
Flaccid paralysis sign
- UMN lesion + LMN lesion
Clasp knife spasticity
+ UMN lesion - LMN lesion
Werdnig-Hoffman Disease (poliomyelitis and spinal muscular atrophy) characteristics
-LMN lesions only -due to destruction of anterior horns -flaccid paralysis
Multiple Sclerosis characteristics
-due to demyelination -mostly affects white matter of the cervical region -random and asymmetric lesions -scanning speech -intention tremor -nystagmus
Amyotrophic lateral sclerosis characteristics
-combined UMN adn LMN deficity w/ no sensory, cognitive or oculomotor deficits
ALS can be caused by a defect in...
superoxide dismutase 1.
ALS commonly presents as...
fasciculations with eventual atrophy and weakness of hands; fatal.
Treatment for ALS
riluzole can modestly increase survival by decreasing presynaptic gluatamate release.
Complete occlusion of the anterior spinal artery characteristics
-spares dorsal columns and Lissauer tract -upper thoraic ASA territory is a wather shed area bc artery of Adamkiewicz supplies ASA below T8
Tabes dorsalis is caused by...
tertiatry syphilis and results from degeneration of the dorsal columns and roots leading to impaired sensation adn proprioception and progressive senosry ataxia (cant feel legs = poor coordination).
Tabes dorsalis is associated with...
Charcot joints, shooting pain, Argyll Robertson pupils.
Argyll Robertson pupils are...
small, bilateral pupils taht further constrict to accomodation and convergence but not to light.
Exam of Tabes dorsalis will demonstrate...
absence of DTRs and + Romberg.
Syringomyelia causes damage to...
the anterior white commissure of the spinothalamic tract (2nd order neurons) leading to bilateral loss of pain and temp.
Vit B12 or E deficiency leads to...
subacute combined degeneration (demyelination of the dorsal columns, lateral corticospinal tracts and spinocerebellar tracts) leading to ataxic gait, paresthesia, impaired position and vibration sense.
Poliomyelitis is caused by...
poliovirus which replicates in the oropharynx and small intestine before spreading via the bloodstream to the CNS.
Poliovirus infection causes destruction of...
cells in the anterior horn of the spinal cord (LMN death).
Symptoms of poliomyelitis
LMN lesion signs (weakness, hypotonia, flaccid paralysis, fasciculations, hyporeflexia, and muscle atrophy) -infection signs (fever, malaise, nausea, etc.)
Findings of poliomyelitis
-CSF w/ increased WBCs and slight increase in protein - virus recovered from stool or throat
Spinal muscular atrophy (Werdnig Hoffmann disease)
congenital degeneration of anterior horns of the spinal cord leading to a LMN lesion; autosomal recessive inheritance
Spinal muscular atrophy presents as...
a "floppy baby" with marked hypotonia and tongue fasciculations
Friedreich ataxia is due to...
an autosomal recessive trinucleotide repeat (GAA) on chr 9 that encodes frataxin (iron binding protein).
Friedreich ataxia causes...
degeneration of multiple spinal cord tracts leading to muscle weakness, loss of DTRs, vibratory sense and proprioception
Friedreich ataxia presents in childhood with...
kyphoscoliosis. -staggering gait -frequent falling -nystagmus -dysarthria -ps cavus -hammer toes -hypertrophic cardiomyopathy (cause of death)
Brown-Sequard syndrome is due to...
hemisection of the spinal cord.
Findings of Brown-Sequard
-ipsilateral UMN signs -ipsilateral loss of tactile, vibration and proprioception -contralateral pain and temp loss -ipsilateral loss of all sensation at the level of the lesion -ipsilateral LMN signs at the level of the lesion
If a brown-sequard lesion occurs above T1, a pat may present with...
Horner syndrome due to damage of the oculosympathetic pathway.
Sympathectomy of the face: -Ptosis -Anhidrosis (and flushing) -Miosis (pupil constriction)
Horner syndrome is associated with...
lesion of the spinal cord above T1. (Pancoast tumor, Brown-Sequard syndrome, late-stage syringomyelia)
The 3-neuron oculosympathetic pathway projects from...
the hypothalamus to the intermediolateral column of the spinal cord then to the superior cervical (sympathetic) ganglion and finally to the pupil, smooth muscle of the eyelid and sweat glands.
posterior half of skull cap
high turtlenck shirt
at the nipple
at the xiphoid process
at the umbilicus
at the inguinal ligament
includes the kneecaps
S2, S3, S4 dermatomes
erection and sensation of penile and anal zones
Diaphragm and gallbladder pai is referred to the...
right shoulder via the phrenic nerve.
C5 nerve root
C7 nerve root
L4 nerve root
S1 nerve root
Primitive reflexes are inhibited by...
a mature/developing frontal lobe and may reemerge in adults with frontal lobe lesions.
"hang on for life" reflex - abduct/extend limbs when startled and then draw them together
movement of head toward one side if cheek or mouth is stroked
sucking response when roof of mouth is touched
curling of fingers if palm is stroked
dorsiflexion of large toe and fanning of others with plantar stimulation (Babinski sign)
stroking along one side of the spine while the newborn is in ventral suspension causes lateral flexion of the lower body toward the stimulated side
CNs that lie medially at the brain stem
III VI XII (motor = medial)
-melatonin secretion -circadian rhythm
conjugate vertical gaze center
paralysis of conjugate vertical gaze due to a lesion in the superior colliculi (pinealoma)
Olfactory - smell **only CN w/o thalamic relay
Optic - sight
Oculomotor - eye movement (SR, IR, MR, IO), pupillary constriction, accomodation, eyelid opening
Trochlear - eye movemetn (SO)
Trigeminal - mastication, facial sensation (ophthalmic, maxillary, mandibular divisions), somatosensation from the anterior 2/3 of the tongue
Abducens - eye movement (LR)
Facial - facial movement, taste from anterior 2/3 of tongue, lacrimation, salivation, eyelid closure, stapedius muscle in ear
The facial nerve courses through...
the parotid gland but does not innervate it.
vestibulocochlear - hearing and balance
Glossopharyngel - taste and somatosensation from posterior 1/3 of tongue, swallowing, salivation, monitoring carotid body and sinus chemo/baro receptors and stylopharyngeus.
The stylopharyngeus acts to...
elevate the pharynx and larynx. Innervated by CN IX.
Vagus - taste from epiglottic region, swallowing, soft palate elevation, midline uvula, talking, coughing, thoracoabdominal viscera, monitoring aortic arch chemo/baro receptors
Accessory - head turning, shoulder shrugging (SCM, Trapezius)
Hypoglossal - tongue movement
Cranial nerve nuclei are located in..
the tegmentum portion of the brainstem.
Midbrain contains cranial nerve nuclei for:
CN III and IV
Pons contains cranial nerve nuclei for:
CN V, VI, VII, and VIII
Medulla contains cranial nerve nuclei for:
CN IX, X, and XII
Spinal cord contains cranial nerve nucleus for:
Corneal reflex afferent
Corneal reflex efferent
Lacrimation reflex afferent
Lacrimation reflex efferent
Jaw jerk afferent
V3 (senosry - muscle spindle from masseter)
Jaw jerk efferent
V3 (motor - masseter)
Pupillary reflex afferent
Pupillary reflex efferent
Gag reflex afferent
Gag reflex efferent
Vagal nuclei (3)
1. nucleus solitarius 2. nucleus ambiguus 3. dorsal motor nucleus
visceral sensory information (taste, baroreceptors, gut distention) VII, IX, X
motor innervation of pharynx, larynx and upper esophagus (swallowing, palate elevation) IX, X, XI
dorsal motor nucleus
sends autonomic (PNS) fibers to the heart, lungs and upper GI X
CN 1 pathway entrance
CN II - VI pathway entrance
middle cranial fossa through the sphenoid bone
Optic canal carries...
CN II ophthalmic artery central retinal vein
Superior orbital fissure carries...
CN III, IV, V1, and VI ophthalmic vein sympathetic fibers
Foramen Rotundum carries..
Foramen Ovale carries...
Foramen spinosum carries...
middle meningeal artery
CN VII- XII pathway entrance
posterior cranial fossa through teh temporal or occipital bone
Internal auditory meatus carries...
CN VII and VIII
Jugular foramen carries...
CN IX, X, XI and jugular vein
Hypoglossal canal carries...
Foramen magnum carries...
spinal roots of CN XI brain stem vertebral arteries
The cavernous sinus is a collection of...
venous sinuses on either side of the pituitary.
The cavernous sinus collects blood from the....
eye and superficial cortex and sends it to the internal jugular vein.
Structures that pass through the cavernous sinus include...
CN III, IV, V1, V2 and VI and postganglionic sympthetic fibers. Also the internal carotid artery.
Cavernous sinus syndrome is...
ophthalmoplegia and decreased corneal and maxillary sensation with normal visual acuity. CN VI is commonly affected.
Cavernous sinus syndrome is due to...
mass effect, fistula, thrombosis, etc.
CN V motor lesion causes...
the jaw to deviate toward the side of the lesion due to unopposed force from the opposite pterygoid muscle.
CN X lesion causes...
the uvula to deviate away from the side of the lesion. The weak side collapses and the uvula points away.
CN XI lesion casues...
weakness turning the head to the contralateral side of the lesion (SCM). Should droop on the side of the lesion (trapezius).
CN XII lesion
tongue deviates toward side of the lesions due to weakened muscles on the affected side
Outer ear is the...
visible portion of the ear (pinna) that includes the auditory canal and eardrum. Transfers sound waves via vibration of the ear drum.
Middle ear is...
an air-filled space with three bones called the ossicles (malleus, incus, stapes).
The ossicles act to...
conduct and amplify sound from the eardrum to the inner ear.
The inner ear is...
the fluid-filled cochlea. It contains the basilar membrane the vibrates secondary to sound waves.
In the inner ear, vibration is transduced via...
specialized hair cells sending an auditory nerve singal to the brainstem.
Each frequency leads to vibration at a specific location on the basilar membrane (tonotopy):
-low frequency is heard at the apex near the helicotrema (wide and flexible) -high frequency is heard best at the base of the cochlea (thin and rigid)
Conductive Hearing Loss test findings
Rinne - abnormal (bone > air) Weber - localizes to affected ear
Sensorineural Hearing loss test findings
Rinne - normal (air > bone) Weber - localizes to unaffected ear
Noise-induced hearing loss is due to...
stereocilliated cells in the organ of Corti; loss of high-frequency hearing first.
Sudden, extremely loud noises can produce hearing loss due to...
tympanic membrane rupture.
UMN facial lesion
contralateral paralysis of lower face; forehead spared due to bilateral UMN innervation
LMN facial lesion
ipsilateral paralysis of upper and lower face
Facial nerve palsy is due to...
complete destruction of the facial nucleus itself or its branchial efferent fibers.
Symptoms of facial nerve palsy
peripheral ipsilateral facial paralysis (drooping smile) with inability to close eye on involved side
Facial nerve palsy is associated with...
Lyme disease, HSV, herpes zoster, sarcoidosis, tumors and diabetes.
Treatment of facial nerve palsy
3 muscles that close the jaw
1. Masseter 2. teMporalis 3. Medial pterygoid M's Munch
1 muscle that closes the jaw
The masseter, temporalis, medial pterygoid and lateral pterygoid are all innervated by...
the trigeminal nerve (V3).
Refractive errors are...
impaired vision that improves with glasses: 1. hyperopia 2. myopia 3. astigmatism 4. presbyopia
Hyperopia is when the eye is...
too short for the refractive power of the cornea and lens causing light to be focused behind the retina.
Myopia is when the eye is...
too long for the refractive power of the cornea and lens and light is then focused in front of the retina.
Astigmatism is an...
abnormal curvature of the cornea resulting in different refractive power at different axes.
a decrease in focusing ability during accomodation due to sclerosis and decreased elasticity.
inflammation of the anterior uvea and iris with hypopyon (sterile pus) accompanied by conjunctival redness.
Uveitis is often associated with...
systemic inflammatory disorders (sarcoid, RA, TB, etc.)
retinal edema and necrosis leading to a scar.
Retinitis is often...
viral (CMV, HSV, HZV) and associated with immunosuppression.
Central retinal artery occlusion is...
blockage of central or branch retinal vein due to compression from nearby arterial atherosclerosis. This causes retinal hemorrhage and edema in the affected area.
Non-proliferative diabetic retinopathy
damaged capillaries lead blood leading to lipids and fluid seeping into the retina leading to hemorrhages and macular edema
Treatment for Diabetic retinopathy
blood sugar control and macular laser
Proliferative diabetic retinopathy
chronic hypoxia results in new blood vessel formation with resultant traction on the retina
Treatment for proliferative diabetic retinopathy
peripheral retinal photocoagulation and anti-VEGF injections
optic disc atrophy with characteristic cupping, usually with increased intraocular pressure and progressive peripheral visual field loss
Open angle glaucoma is associated with...
increased age, AA race, family history. It is painless and more common in US.
Secondary open angle glaucoma is due to...
blocked trabecular meshwork from WBCs, RBCs and retinal elements
Primary closed angle glaucoma is due to...
enlargement of the lens against the centril iris leadings to obstruction of normal aqueous flow through the pupil leading to fluid building up behind the iris, pushing the peripheral iris against the cornea and impeding flow through the trabecular meshwork
Secondary closed angle glaucoma is due to..
hypoxia from retinal disease that induces vasoproliferation in the iris that contracts the angle
Chronic closure (glaucoma) is often...
asymptomatic with damage to the optic nerve and peripheral vision.
Acute closure (glaucoma) is a true...
ophthalmic emergency. Increased intraocular pressure pushes the iris forward leading to abrupt angle closure.
Acute closure glaucoma presents with...
extreme pain, sudden vision loss, halos around lights, rock-hard eye, and frontal HA.
Epinephrine should not be given for acute closure glaucoma due to...
it mydriatic effect.
A cataract is...
a painless, often bilateral, opacification of the lens leading to a decrease in vision.
Risk factors for Cataract
-increased age -smoking -alcohol -excessive sunlight -prolonged corticosteroid use -classic galactosemia -galactokinase deficiency -diabetes -trauma -infxn
optic disc swelling due to increased intracranial pressure
Findings of Papilledema
enlarged blind spot and elevated optic disc with blurred margins seen on fundoscopic exam
CN III damage
eye looks down and out; ptosis, pupillary dilation and loss of accomodation
CN IV damage
eye moves upward (especially w/ contralateral gaze and head tilt)
People with CN IV damage may have problems with...
going down the stairs and will present with a compensatory head tilt in the opposite direction.
CN VI damage
medially directed eye that cannot abduct
pupil constriction controlled parasympathetically.
Miosis nerve pathway
1st neuron: Edinger-Westphal nucleus to ciliary ganglion via CN III 2nd neuron: short ciliary nerves to pupillary sphincter muscles
pupil dilation controlled sympathetically.
Mydriasis nerve pathway
1st neuron: hypothalamus to ciliospinal center of Budge 2nd neuron: exit at T1 to superior cervical ganglion 3rd neuron: plexus along the internal carotid, through the cavernous sinus; enters orbit as long ciliary nerve to pupillary dilator muscles
The pupillary light reflex is when light in...
the retina sends a signal via CN II to pretectal nuclei in the midbrain that activates bilateral Edinger-Westphal nuclei.
Result of the pupillary light reflex
illumination of 1 eye results in bilateral pupillary constriction
Marcus Gunn pupil is an...
afferent pupillary defect due to optic nerve damage or severe retinal injury leading to decreased bilateral pupillary constriction to light is in the affected eye.
Marcus Gunn pupil can be tested with the...
"swinging flashlight test".
Motor output of CN III to the ocular muscles is affected primarily by..
vascular disease due to decreased diffusion of oxygen adn nutrients to the interior fibers from compromised vasculature that resides on the outside of a nerve
Signs of damage to the motor portion of CN III
ptosis; down and out gaze
Damage to the parasympathetic output of CN III is due to..
compression (ex. posterior communicting artery aneurysm or uncal herniation).
Signs of damage to the parasympathetic output of CN III
diminished or absent pupillary light reflex, "blown pupil" often with down and out gaze
Retinal detachment is...
separation of neurosensory layer of retina (photoreceptor layer w/ rods and cones) from the outermost pigmented epithelium leading to degerenration of photoreceptors and vision loss.
Retinal detachment may be secondary to...
retinal breaks, diabetic traction and inflammatory effusions.
Retinal breaks are more common in pts with...
high myopia and are often preceded by posterior vitreous detachment (flashes and floaters) and monocular loss of vision like a "curtain drawn down".
Age-related macular degeneration causes...
distortion (metamorphopsia) and eventual loss of central vision (scotomas).
Dry macular degeneration
deposition of yellowish extracellular material in and beneath the Bruch membrane and retinal pigment epithelium (drusen) with a gradual decrease in vision
Dry macular degeneration progress can be prevented with...
multivitamin and antioxidants.
Wet macular degeneration is...
rapid loss of vision due to bleeding secondary to choroidal neovascularization.
Wet macular degeneration can be treated with...
anti-VEGF or laser.
When an image hits the visual cortex, it is...
upside down and left-right reversed.
The Meyer loop carries signals from the...
inferior retina and loops around the inferior horn of the lateral ventricle.
The Dorsal optic raiation carries signals from the..
superior retina and takes the shortes path via the internal capsule.
The medial longitudinal fasciculus (MLF) is a...
pair of tracts that allows for crosstalk between CN VI and CN III nuclei.
The MLF coordinates...
both eyes to move in the same horizontal direction.
The MLF is highly...
myelinated so lesions are seen in pts with demyelination (MS).
A lesion in the MLF causes..
Internuclear ophthalmoplegia (INO).
Lesions in the MLF (aka INO) causes a lack of communication such that when the CN VI nucleus activates the ipsilateral lateral rectus, the...
contralateral CN III nucleus does not stimulate the meddial rectus. Thus, the abducting eye gets nystagmus (bc CN VI overfires to stimulate CN III).
Dementia is a...
decrease in the cognitive ability, memory or function w/ intact consciousness.
The most common cause of dementia in the eldely is...
The familial form (10%) of Alzheimer is associated with the following proteins:
-Early onset: APP, presenilin-1, presenilin-2 -Late onset: ApoE4
protective for Alzheimer.
Gross findings of Alzheimer
-cortical atrphy -narrowing of gyri -widening of sulci
Histologic findings of Alzheimer
-senile plaques -neurofibrillary tanlges (also decreased ACh)
Senile plaques have an...
extracellular beta-amyloid core. They may cause amyloid angiopathy leading to intracranial hemorrhage.
Abeta (amyloid-beta) is synthesized by..
cleaving amyloid precursor protein (APP).
Neurofibrillary tangles are...
intracellular, hyperphosphorylated tau protein = insoluble cytoskeletal elements. The number of tangles correlates with the degree of dementia.
Pick disease (frontotemporal dementia) presents with...
dementia, aphasia, parkinsonian aspects, and change in perosnality. Frontotemporal atrophy.
Pick disease spares the...
parietal lobe and posterior 2/3 of the temporal gyrus.
Pick bodies are...
spherical tau protein aggregates.
Lewy body dementia presents with...
initial dementia and visual hallucinations followed by parkinsonian features.
Lewy body dementia is due to a defect in...
Cretuzfeldt-Jakob disease is...
rapidly progressive dementia with myoclonus.
Findings of Creutzfeldt-Jakob
-spongiform cortex -prions (PrPsc sheet = beta-pleated sheet resistant to proteases)
Other causes of dementia (7)
-multi infarct -syphilis -HIV -vitamins -B1, B3, B12 deficiency -Wilson disease -NPH
Multiple sclerosis is...
autoimmune inflammation and demyelination of the CNS.
MS pts present with...
-optic neuritis (sudden loss of vision resulting in Marcus Gunn pupils) -internuclear ophthalmoplegia (INO) -hemiparesis -hemisensory symptoms -bladder/bowel incontinence
MS most often affects...
whites, women in 20s or 30s.
MS findings (4)
-increased protein (IgG) in the CSF -oligoclonal bands (diagnostic) -periventricular plaques -multiple white matter lesions separated in time and space
Periventricular plaques are...
areas of oligodendrocyte loss and reactive gliosis.
Gold standard for diagnosis MS is...
Treatment for MS
-beta-interferon -immunosuppression -Natalizumab
Symptomatic treatment for MS
-bladder: cath, muscarinic antagonists -spasticity: baclofen, GABA receptor agonist -pain: opioids
Acute inflammatory demyelinating polyradiculopathy is an..
autoimmune condition that destroys schwann cells leading to inflammation and demyelination of peripheral nerves and motor fibers.
Acute inflammatory demyelinating polyradiculopathy results in...
symmetric ascending muscle weakness/paralysis beginning in the lower extremities. Facial paralysis in 50%. Autonomic function affected (cardiac irregularities, bp change).
Acute inflammatory demyelinating polyradiculopathy is the most common variant of...
Findings of acute inflammatory demyelinating polyradiculopathy
-increased CSF protein w/ normal cell count -papilledema
Acute inflammatory demyelinating polyradiculopathy is associated with...
infections (Campylobacter jejuni and CMV) leading to an autoimmune attack of peripheral myelin due to molecular mimicry. Also, inoculations and stress.
Treatment for acute inflammatory demyelinating polyradiculopathy
-respiratory support -plasmapheresis -IVIG
Progressive multifocal leukoencephalopathy (PML) is...
demyelination of the CNS due to destruction of oligodendrocytes.
PML is associated with...
JC virus and seen in 3% of AIDS pts.
PML is rapidly...
progressive and usually fatal. Increased risk with Natalizumab.
Acute disseminated encephalomyelitis is...
multifocal perivenular inflammation and demyelination after infxn (measles/VZV) or certain vaccinations (rabies/smallpox).
Metachromatic leukodystrophy is an...
autosomal recessive lysosomal storage disease due to arylsulfatase A deficiency.
In metachromatic leukodystrophy, deficiency of arylsulfatase A leads to a...
buildup of sulfatides causing impaired production of myelin.
Findings of metachromatic leukodystrophy
central and peripheral demyelination with ataxia, dementia
Charcot-Marie-Tooth disease is a group of...
progressive, hereditary nerve disorders related to the defective production of proteins involved in the structure and fxn of peripheral nerve or the myelin sheath.
Charcot-Marie-Tooth disease is associated with...
scoliosis and foot deformities. AD inheritance.
Krabbe disease is a...
autosomal recessive lysosomal storage disease due to deficiency of galactocerebrosidase leading to buildup of galactocerebroside and psychosine which destroys the myelin sheath.
Findings of Krabbe disease
-peripheral neuropathy -developmental delay -optic atrophy -globoid cells
Adrenoleukodystrophy is an...
X-linked disorder affecting males that disrupts the metabolism of very-long-chain fatty acids leading to excessive buildup in the nervous system, adrenal gland and testes.
Partial seizures affect...
1 area of the brain. Most commonly originate in the medial temporal lobe.
Partial seizure are often preceded by...
Types of partial seizure
1. simple partial 2. complex partial
Simple partial seizures
consciousness intact; affect motor, sensory, autonomic and psychic factors
Complex partial seizures have..
Generalized seizures are...
diffuse. Types: 1. Absence 2. Myoclonic 3. Tonic-Clonic 4. Tonic 5. Atonic
Absence seizure features
-3 hz -no postictal confusion -blank stare
Myoclonic seizure features
-quick, repetitive jerks
-alternating stiffening and movement
"drop" seizures (falls to floor)
Epilepsy is a disorder of...
continuous seziure for > 30 min or recurrent seizures w/o gaining consciousness for > 30 min
Causes of seizure in children
genetic infection trauma congenital metabolic
Causes of seizure in adults
tumors trauma stoke infection
Causes of seizure in the elderly
stroke tumor trauma metabolic infection
Localization and duration of cluster headaches
unilateral 15 min-3 hr; repetitive
Description of cluster HAs
repetitive brief HAs; excruciating periobrital pain w/ lacrimation adn rhinorrhea; may induce Horner; more common in males
Treatment of Cluster HAs
inhaled oxygen sumatriptan
Localization and duration of tension headaches
bilateral >30 min (usually 4-6 hrs)
Description of tension HAs
-steady pain -no photophobia or phonophobia -no aura
Treatment of tension HAs
-analgesics, NSAIDs, acetaminophen -amitriptyline (for chronic pain)
Migraine localization and duration
-unilateral -4-72 hrs
Description of Migraine
-pulsating pain w/ nausea, photophobia or phonophobia -may have "aura"
Migraine is due to...
irritation of CN V, meninges, or blood vessels (release of substance P, CGRP, vasoactive peptides).
-abortive (triptans, NSAIDs) -prophylactic (propranolol, topiramate, calcium channel blcokers, amitriptyline)
Cluster HAs can be differentiated from trigeminal neuralgia based on...
duration. trigeminal neuralgia produces repetitive shooting pain that lasts for less than one minute.
a sensation of spinning while actually stationary.
Peripheral vertigo etiology is...
inner ear (semicircular canal debris, vestibular nerve infxn, meniere)
Positional testing of peripherla vertigo shows...
delayed horizontal nystagmus
Central vertigo etiology is...
brainstem or cerebellar lesion (stroke, etc).
Findings of central vertigo
directional change of nystagmus skew deviation diploplia dysmetria
Positional testing of central vertigo shows...
immediate nystagmus in aany direction; (focal neurologial findings are also present)
congential, non-inherited, developmental anomaly of neural crest derivatives (mesoderm/ectoderm) due to an activating mutation of GNAQ gene
small blood vessels causing port-wine stain on face, ipsilateral leptomeningeal angioma (causing seizures/epilepsy); intellectual disability; and episcleral hemangioma (leading to increased IOP and early onset glaucoma).
HAMARTOMAS -Hamartomas -Angiofibromas -Mitral regurgitation -Ash-leaf spots -cardiac Rhabdomyoma -Tuberous sclerosis -autosomal dOminant -Mental retardation -renal Angiomyolipoma -Seizures, Shagreen patches
Tuberous sclerosis pts have an increased incidence of...
subependymal astrocytomas and ungual fibromas.
Neurofibromatosis type I findings
-cafe-au-lait spots -Lisch nodules (pigmented iris hamartomas) -neurofibromas in skin, optic gliomas, pheochromocytomas
Neurofibromatosis type I is due to...
a mutated NF1 tumor suppressor gene (neurofibromin, negative regulator of Ras).
Skin tumors of NF1 are derived from..
neural crest cells.
von Hippel-Lindau disease findings
-cavernous hemangiomas in the skin, mucosa, organs -bilateral RCC -hemangioblastoma in retina, brain stem and cerebellum -pheochromocytoma
von Hippel-Lindau inheritance and pathology
-autosomal dominant -mutated VHL tumor suppressor which results inconstitutive activity of HIF and activation of angiogenic growth factors
Glioblastoma multiforme is a common...
highly malignant primary brain tumor with about one year survival. It is a grade IV astrocytoma.
Glioblastoma multiforme is found in the...
cerebral hemisphers anc can cross the corpus callosum ("butterfly glioma").
Glioblastoma multiforme stains with...
GFAP (for astrocytes).
Histology of glioblastoma multiforme
pseudopalisading pleomorphic tumor cells that border a central area of necrosis and hemorrhage
Meningioma is a common...
benign, primary brain tumor.
Meningioma most commonly occurs in the...
convexities of the hemispheres.
Menigiomas arise from...
arachnoid cells, is extra-axial and may have a dural attachment.
Meningioma is often asymptomatic but may present with..
seizures or focal neurological signs. Can treat with resection or radiosurgery.
Histology of meningioma
spindle cell concentricall arranged in a whorled pattern; psammoma bodies
Hemangioblastoma is most often...
cerebellar. It can produce erythropoietin leading to secondary polycythemia.
Hemangioblastoma is associated with...
von Hippel-Lindau syndrome when found with retinal angiomas
closely-arranged, thin-walled capillaries with minimal interleaving parenchyma
Schwannoma is ususally found at...
the cerebellopontine angle and has schwann cell origin.
Schwannoma is positive for..
Schwannoma is often localized to...
CN VIII causing acoustic schwannoma.
Oligodendroglioma is relatively...
rare and slow growing. It is most often in the frontal lobes.
-chicken-wire capillary pattern -often calcified
-fried egg cells (round nuclei w/ clear cytoplasm)
Pituitary adenoma is most commonly a...
Pituitary adenomas cause...
bitemproal hemianopia (due to pressure on optic chiasm). and hyper/hypo pituitarism.
Childhood primary brain tumors (4)
1. pilocytic astrocytoma 2. medulloblastoma 3. ependymoma 4. craniopharyngioma
Pilocytic astrocytoma features
-well-circumscribed -found in posterior fossa -GFAP + -benign
Pilocytic astrocytoma histology
-rosenthal fibers (eosinophilic, corkscrew fibers)
Medulloblastoma is a highly...
malignant cerebellar tumor (form of primitive neuroectomderm)
compress the 4th ventricle causing hydrocephalus and can send "drop metastases" to the spinal cord.
Homer-Wright rosettes small blue cells
Ependymoma is most commonly found in..
the 4th ventricle and can cause hydrocephalus. Poor prognosis.
Histology of ependymoma
-perivascular rosettes -rod-shaped blepharoplasts found near nucleus
Craniopharyngioma is a...
benign tumor. Most common childhood supratentorial tumor. Calcification is common. Can cause bitemporal hemianopia.
Craniopharyngioma is derived from...
remnants of Rathke pouch.
Cingulate herniation is under the...
falx cerebri and can compress the anterior cerebral artery.
Uncal herniation compresses...
the ipsilateral CN III, ipsilateral PCA, and the contralateral crus cerebri (ipsilateral paralysis; false localization sign).
Cerebellar tonsiallar herniation is into the...
foramen magnum. Coma and death result when these herniations compress the brain stem (and inhibit respiration).