Neuro Flashcards
What does the notochord induce formation of?
Notochord causes the overlying ectoderm to differentiate into neuroectoderma nd form the neural plate
What does the neural plate give rise to?
neural tube and neural crest cells
What does the notochord give rise to?
nucleus pulposus of the intervertebral disc in adults
What does the alar plate give rise to?
(dorsal), sensory info
what does the basal plate give rise to?
(ventral) motor
What are the 3 primary vesicles of the developing brain?
Forebrain (prosencephalon), Midbrain (mesencephalon), and hindbrain (rhombencephalon)
What secondary vesicles does the prosencephalon give rise to?
telencephalon and diencephalon
What does the mesencephalon give rise to?
Midbrain and Aqueduct
Which secondary vesicles does the rhombencephaol derive?
Metencephalon and myelencephaol
What structures come from the telencephalon?
cerebral hemisphere and lateral ventricles
What structures come from the diencephalon?
thalamus and 3rd ventricle
What structures come from the metencephalon?
pons, cerebellum, and upper part of 4th ventricle
What structures come from the myelencephalon?
medulla and lower part of the 4th ventricle
Neuroectoderm makes which brain strucutres?
CNS neurons, ependymal cells (inner lining of ventricles, makes CSF), oligodendroglia; astrocytes
Neural crest cells make what brain strucutres?
PNS neurons, Schwann cells
Mesoderm makes what brain structures?
Microglia
Spina bifida occulta?
failure of bony spinal canal to close, but no structural herniation. tuft of hair at lower veretbral level where the defect is located.

Meningocele?
meninges (but not the spinal cord), herniate through spinal canal defect. Normal AFP

Meningomyelocele?
meninges and spinal cord herniate through spinal canal defect

Anencephaly? What condition is it associated with?
anterior neural tube malformation, no forebrain, open calvarium “frog-like appearance”. inc AFP, polyhydramnio (cannot swallow amniotic fluid), maternal diabetes type I, supplement with folate to reduce the risk
Holoprosencephaly? What is the mutation?
Left and right hemisphere don’t separate during weeks 5-6. mutations of sonic hedgehog signaling pathway. Cyclopia or cleft lip/palate
Chiari II Arnold-Chiari malformation?
herniation of cerebellar tonsil and vermis through foramen magnum with aqueductal stenosis and hydrocephalus. Presents with lumbosaral myelomeningocele and paralysis below the defect.
Arnold sounds like a guy who would use a magnum
Dandy-Walker?
agenesis of cerebellar vermis with sycystic enlargememnt of 4th ventricles. Hydrocephalus and spina bifida (someone who walks dandy probably has a vermis issue)
Syringomyelia findings? What malformation is associated wtih it?
“cape-like” bilateral loss of pain and temperature sensation in upper extremities (fine touch sensation is preserved). Associated with chiari I malformation
Tongue innervations?

Medial medullary syndrome?
infarct of paramedian branches of ASA and vertebral arteries
Lateral medullary (Wallenberg) syndrome?
Stroke of the PICA. Nucleus ambiguus effects are specific to PICA lesions “Dont pick a (PICA) horse (hoarseness) that can’t eat (dysphagia)”
Lateral pontine syndrome?
AICA stroke. Facial nucleus effects are specific to AICA lesions. “Facial droop means AICA’s pooped”
Paralysis of face
What diseases commonly present with berry aneurysms?
ADPKD, Ehlers’Danlos, and Marfan (also AVM)
Where are charcot-bouchard microaneurysms?
In the small vessels of the basal ganglia and thalamus. Due to chronic hypertension
Central post-stroke pain syndrome?
neuropathic pain due to thalamic lesions. Allodynia (ordinarily painless stimuli cause pain) and dysaesthesia (unpleasant sense of touch)
What is ruptured in an epidural hematoma?
middle meningeal artery (branch of the maxillary artery which comes from the 1st aortic arch derivative)
Presenting symtoms of epidural hematoma?
Have a lucid interval, then coma. transtentorial herniation and CN III palsy
CT shows biconvex (lentiform) hyperdense blood collection not crossing suture lines, but can cross falx, tentorium?
epidural hematoma
What ruptures in a subdural hematoma?
bridging veins
Which populations tends to get subdural hematomas?
Elderly (alzheimers/brain atrophy), alcoholics, people who have trauma, and babies (shaken baby syndrome)
WHat type of intracranial hemorrhage presens as a crescent-shaped hemorrhage that crosses the suture lines resulting in a midline shift?
Subdural hematoma. Cannot cross falx, tentorium
What is ruptured in a subarachnoid hemorrhage?
aneurysm such as a berry/saccular anuerysm.
What are the symptoms of sybarachnoid hemorrhage?
“worst headache of my life”. Rapid time course with a bloody or yellow spinal tap.
What is the major risk following a subarachnoid hemorrhage?
risk of vasospasm 2-3 days afterward, due to blood breakdown. WIll have altered mental status and focal neurologic deficits. Tx with nimodipine (CCB)
What causes intraparenchymal (hypertensive) hemorrhage?
systemic hypertension. Also seen with amyloid angiopathy, vasculitis, and neoplasm.
Where does an intraparenchyma hemorrhage occur?
basal ganglia and internal capsule. Charcot-Bouchard aneurysm of lenticulostriate vessels, but can be lobar.
Which regions of the brain are most vulnerable to hypoxia?
hippocampus, neocortex, cerebellum, watershed areas.
hypoxia–hypocampus is most vulnerable
How do you exclude hemorrhagic stroke?
Absense of bright areas on noncontract CT exclude hemorrhagic stroke (so don’t use tPA!)
What are the histological features seen in stroke?
12-48 hours–red neurons
24-72 hours–Necrosis + neutrophils
3-5 days–Macrophages
1-2 weeks– Reactive gliosis + vascular proliferation
>2 weeks – glial scar
What is the most common site of hemorrhagic stroke?
basal ganglia
What is communicating hydrocephalus?
decreased CSF absorption by arachnoid granulations, leads to increased ICP, papilledema, and herniation (due to arachnoid scaring post-meningitis)
What is hydrocephalus ex vacuo?
Apparent inc in CSF on imaging due to dec neural tissue due to neuronal atrophy. ICP is normal. Seen in alzheimer disease, advanced HIV, Pick disease
Noncommunicating hydrocephalus?
Structural blockage of CSF circulation within the ventricular system (stenosis of aqueduct of sylvius)
What herniates in a vertebral disc herniation?
nucleus pulposus (soft central disc) herniates through the annulus fibrosus (outer ring). Usually occurs posterolaterally at L4-L5 or L5-S1
Where is a lumbar puncture performed?
TO keep the cord alive, keep the spinal needle between L3-L5. (spinal cord ends at L1-L2 and subarachnoid space extend to S2)
Does poliomyelitis present with UMN or LMN symptoms?
LMN
Spinal muscular atrophy (Werdnig-Hoffmann disease)?
Congenital degeneration of anterior horns of spinal cord, LMN lesion. “Floppy baby” with hypotonia and tongus fasciculations. AR and death by 7 months
Friedreich Ataxia mnemonic ?
Friedreich is Fratastic (frataxin): he’s you’re favorite frat brother, always stumbling, staggering, and falling, but has a big heart.
Degeneration of dorsal column and spinocerebellar tracts. Presents with loss of reflexes, impaired vibratory and proprioception, staggering gait, failling, nystagmus, dysarthria, pes cavus, hammer toes and hypertrophic cardiomyopathy
Horner syndrome mnemonic?
PAM is horny
ptosis, anhidrosis, and miosis
loss of sympathetics to the face
What are the common causes of horner syndrome?
pancoast tumor, Brown-Sequard syndrome, late-stage syringomyelia. Anything assoaited with lesion of spinal cord above T1.
Mnemonic for the clinical reflexes?
S1, 2–“buckle my shoe” achilles reflex
L3,4– “kick the door” patellar reflex
C5, 6– “pick up sticks” biceps reflex
C7, 8 – “lay them straight” triceps reflex
L1, 2– “testicles move” cremaster reflex
S3, 4 “winks galore” anal wink reflex
What structure is the conjugate vertical gaze center?
superior colliculi
What structure is the auditory center?>
Inferior colliculi
What cranial nerve nuclei develop in the midbrain?
CN III, IV
What cranial nerve nuclei develop in the pons?
CNV, VI, VII, VIII
What cranial nerve nuclei are in the medulla?
CN IX, X, XII
What cranial nerve nuclei are in the spinal cord?
CN XI
What is the corneal reflex?
Afferent: V1 nasociliary
Efferent: VII
What is the lacrimation reflex?
Afferent: V1
Efferent: VII
What is the jaw jerk reflex?
V3 afferent and efferent
What is the pupillary reflex?
Afferent: CNII
Efferent: CNIII (parasympathetics)
What is the gag reflex?
Afferent: CN IX
Efferent: CN X
Cavernous sinus syndrome?
Due to mass effect, fistula, thrombosis. Causes ophthalmoplegia and dec corneal and maxillary sensation with normal visual acuity. CN VI commonly affected.
What is subacute combined degeneration?
Due to B12 deficiency and results in degeneration of dorsal columns, descending lateral corticospinal tracts (UMN signs), and spinocerebellar tracts.
What presents with both UMN and LMN lesions?
Amytrophic lateral sclerosis
What type of hydrocephalus is common in Alzheimers?
Hydrocephalus ex vacuo (apparent increase in CSF due to atrophy of cortex. Normal pressure)
What is pseudotumor cerebri?
inc ICP with normal CSF and normal neuro imaging. Manifests as headache and papilledema, common in young obese women.
What is the first sign of an uncal lesion?
fixed, dilated pupil on the same side of the lesion
Is there a loss of consiousness in a myoclonic seizure?
No, just jerking repetitive meovements. No post-ictal state
How do you treat generalized seizures (myoclonic, tonic-clonic, tonic, atonic)?
Broad spectrum anti-convulsants (lamotrigine, levetiracetam, topiramate, valproic acid)
Treatment of focal seizures?
Narrow spectrum anticonvulsants (carbamazepine, gabapentin, phenobarbital or phenytoin)
What fibers does CN7 (facial nerve) carry?
- Motor output to facial muscles
- Parasympathetic innervation to lacrimal, submandibular, and sublingual salivary glands
- Special afferent fibers for taste (chorda timpani) to anterior 2/3 of tongue
- Somatic afferents from pinna and external auditory canal
What is entacapone?
Prevents dopamine breakdown. COMT inhibitors that prevent L-dopa breakdown, inc dopamine availability
What nerve is messed up in Bell Palsy?
CN7- idiopathic lesion. Peripheral ipsilateral facial paralysis, with inability to close eye on affected side. May also have dec tearing, hyperacusis and loss of taste sensation over anterior 2/3 of tongue