Neuro Flashcards
markers in neural tube defects
- high alpha feto protein (AFP) - except in spina bifida occulta
- Ache as a confirmatory test
holoprosencephaly
- failure of left and right hemispheres to separate
- mutations in sonic hedgehog
- in trisomy 13 and fetal alcohol syndrome
- monoventricle and fusion of basal ganglia
** hint: prosencephaly is forebrain
Chiari malformation 1
- ectopia of cerebellar tonsils (one structure)
- presents in adulthood with headaches and cerebellar symptoms
Chiari malformation 2
- herniation of cerebellar vermis and tonsils (2 structures)
- aqueductal stenosis leads to hydrocephalus
- associated with lumbosacral meningomyelocele
Dandy-Walker syndrome
- agenesis of cerebellar vermis with enlarged 4th ventricle
- associated with noncommunicating hydrocephalus and spina bifida
syringomyelia
- cystic cavity within central canal of spinal cord
- anterior white commissure is damaged first
- bilateral loss of pain and temp in upper extremities
- associated with Chiari malformations
astrocytes
- provide physical support, repair, K+ buffer, removal of neurotransmitter, form BBB, glycogen fuel
- derived from neuroectoderm
marker of astrocyte
GFAP
microglia
- phagocytic scavenger or CNS
- mesodermal
- can form giant cells in HIV
Schwann cells are derived from….
neural crest
oligodendrocytes
- add myelin in CNS
- can myelinate many axons
- looks like “fried egg”
free nerve endings
- C = slow, unmyelinated
- Adelta = fast, myelinated
- for pain and temp
Meissner corpuscles
- large, myelinated fibers, adapt quickly
- fine/light touch, position sense in skin
Pacinian corpuscles
- large, myelinated fibers
- vibration and pressure in deep tissue
Markel discs
- large, myelinated fibers
- pressure, static touch, position sense in finger tips
Ruffini corpuscles
- dendritic endings
- pressure, joint angle changes in finger tips
chromatolysis
- reaction of neuronal cell body to axonal injury
- increased protein synthesis in effort to repair damage
- round cellular swelling
- displacement of nucleus
- Dispersion of Nissl substance
3 layers of BBB
- astrocyte foot processes
- capillary membrane
- basement membrane
areas not protected by BBB
inputs of hypothalamus
- area postrema (vomiting after chemo)
- OVLT - organum vasculosum lamina terminalis (osmotic sensing)
functions of hypothalamus
homeostasis by TAN HATS Thirst and water balance Adenohypophysis - anterior pituitary Neurohypophysis - posterior pituitary Hunger Autonomic nerves Temperature Sexaul urges
lateral area of hypothalamus
hunger
- destruction leads to anorexia and failure to thrive
- stimulated by ghrelin, inhibited by leptin
ventromedial area of hypothalamus
satiety
- destruction = get fat
anterior hypothalamus
cooling, parasympathetic (A/C)
posterior hypothalamus
heating, sympathetic
suprachiasmatic nucleus of hypothalamus
circadian rhythm (need sleep)
supraoptic and paraventricular nuclei of hypothalamus
ADH and oxytocin
order of sleep waves
at night BATS Drink Blood B - Beta when awake A - Alpha when awake with eyes closed T - Theta with light sleep N1 S - Sleep spindles and K complexes in N2 D - Delta waves in deep sleep N3 B - Beta waves in REM sleep
VPL (ventral posterolateral) of thalamus
- Vibration, Pain, Pressure, Proprioception, and Light touch, Temp (VPPPL)
- input from spinothalamic and dorsal columns/medial lemniscus
purpose of thalamus
relay for all ascending sensory information
VPM (ventral posteromedial) of thalamus
- face sensation and taste
- input from trigeminal and gustatory pathway
- hint: Makeup goes on the Face
lateral geniculate nucleus of thalamus
- input from CNII
- for vision to calcarine sulcus
- hint: lateral = light
medial geniculate nucleus of thalamus
- input from superior olive and inferior colliculus of tectum
- for hearing to auditory cortex of temporal lobe
- hint: medial = music
ventral lateral nucleus of thalamus
- from basal ganglia and cerebellum
- for movement
limbic system
- emotion, long term memory, olfaction, behavior modification, ANS functions
Papez circuit
- hippocampus, mammillary bodes, anterior thalamic nuclei, cingulate gyrus, entorhinal cortex
- 5 Fs - feeding, fleeing, fighting, feeling and fucking
less activity of mesocortical pathway
more negative symptoms (anergia, apathy, lack of spontaneity)
more activity of mesolimbic pathway
more positive symptoms (delusions, hallucinations)
less activity of nigrostriatal pathway
extrapyramidal symptoms (dystonia, akathisia, parkinsonism, tardive dyskinesia)
less activity of tuberoinfundibular pathway
more prolactin, lower libido, sexual dysfunction, galactorrhea, gynecomastia
inputs of cerebellum
- contralateral cortex via middle cerebellar peduncle
- ipsilateral proprioceptive information vis inferior cerebellar peduncle from spinal cord
output of cerebellum
- Purk(in)je cells are always inhibitory = from deep nuclei of cerebellum to contralateral cortex via superior cerebellar peduncle
lateral cerebellar lesions
- affect the Limbs
- fall toward injured side
medial cerebellar lesions
- affects midline
- truncal ataxia and wide based gait
basal ganglia
important for voluntary movements and postural adjustments
- includes caudate, putamen and globus pallidus
excitatory pathway of basal ganglia
cortical inputs stimulate striatum, leading to GABA release, which inhibits GABA release from GPi, disinhibiting the thalamus
inhibitory pathway of basal ganglia
cortical inputs stimulate striatum, releasing GABA that diminishes subthalamic nucleus via GP externa inhibition, and STN inhibits the thalamus
D1 vs D2 receptors
D1 - direct pathway leading to stimulation of movement
D2 - indirect pathway leading to inhibition of movement
primary motor vs somatosensory in cortex
motor is in front of central sulcus (frontal), somatosensory is behind (parietal)
homunculus medial to lateral
medial = lower limbs lateral = upper limbs and face
cerebral perfusion is driven by…
CO2
what causes decreased cerebral perfusion
increased intracranial pressure or decreased mean arterial pressure
purpose of therapeutic hyperventilation
decrease in CO2 leads to vasoconstriction and decrease in intracranial pressure
anterior artery supplies….
anteromedial surface
middle cerebral artery supplies….
lateral surface
posterior cerebral artery supplies….
posterior and inferior surfaces
cranial nerves that are medial
3,4,6,12
superior vs inferior colliculi
- on dorsal side of brainstem
- superior = conjugate vertical gaze center
- inferior = auditory
- hint: eyes are above your ears
medial cranial nerves are…
motor (3,4,6, 12)
foramen rotundum
CN V2
foramen ovale
CN V3
foramen spinosum
middle meningeal artery
superior orbital fissure
CN 3,4,6, V1
internal auditory meatus
CN 7,8
jugular foramen
CN 9,10,11 and jugular vein
hypoglossal canal
CN 12
oculomotor nerve
CN 3
- eye movement, pupillary constriction (Edinger-Westphal nucleus, muscarinic receptors), accommodation, eyelid opening
trigeminal nerve
CN 5
- mastication, facial sensation, somatosensation from anterior 2/3 of tongue
facial nerve
CN 7
- facial movement, taste from anterior 2/3, lacrimation, salivation (submandibular and sublingual), auditory volume modulation (stapedius)
glossopharyngeal nerve
CN 9,
- taste and sensation from posterior 1/3 of tongue, swallowing, salivation from parotid, carotid body and sinus, elevation of pharynx/larynx
vagus
CN X
- taste from supraglottic region, swallowing, soft palate elevation, uvula, talking, cough, parasympathetics to viscera, aortic arch receptors
nucleus Solitarius
visceral Sensory (CN 7, 9, 10) - taste, pressure, distension)
nucleus aMbigious
motor innervation of pharynx larynx and esophagus (CN 9, 10, 11)
dorsal motor nucleus
autonomic parasympathetic fibers to visceral organs (CN X)
corneal nerve reflexes
afferent - V1
efferent - 7
lacrimation reflex
afferent - V1
efferent - 7
pupillary reflex
afferent - 2
efferent - 3
gag reflex
afferent - 9
efferent - 10
muscles of mastications
closing - masseter, temporalis, medial pterygoid
opening - lateral pterygoid
spinal nerve exiting
C1-C7 above, C8 above T1, all others below
end of spinal cord
L1-L2, lumbar puncture performed at L4
dorsal columns are organized…..
are you are, with your arms by your side
function of dorsal column
vibratory and position sense, pressure and fine touch
function of spinothalamic pathway
pain, temperature (lateral) crude touch, pressure (anterior)
function of corticospinal tract
voluntary movement of limbs
describe the track of dorsal column
- ascends ipsilateral
- synapses in nucleus gracilis, nucleus cuneatus in ipsilateral medulla
- decussates in medulla
- ascend contralaterally in medial lemniscus
- synapse in VPL
describe track of spinothalamic tract
- enters spinal cord
- synapse in ipsilateral gray matter
- decussates at anterior white commissure
- ascends contralaterally
- synapse in VPL
describe track of lateral corticospinal track
- starts at motor cortex
- descends ipsilaterally through internal capsule
- decussate at caudal medulla (pyramidal decussation
- descends contralaterally
- synapses in anterior horn
- LMN to muscle fiber
achilles reflex
S1, S2
patellar reflex
L3-L4
biceps and brachioradialis reflex
C5, C6
triceps reflex
C7, C8
cremasteric reflex
L1 L2
anal wink reflex
S3 S4
moro relfex
“hang on for life” extend arms, than draw together
rooting reflex
head toward stroking, nipple reflex
babinski reflex
dorsiflex of large toe and splaying of others
frontal lobe lesion
disinhibition in concentration, orientation, judgment, primitive reflexes
frontal eye fields lesion
eyes look toward lesion
paramedian pontine reticular formation (PPRF) lesions
eyes look away from side of lesions
medial longitudinal fasciculus (MLF) lesions
internuclear ophthalmoplegia (impaired adduction of ipsilateral eye, nystagmus of contralateral eye with abduction) - in MS
dominant parietal lesion
Gerstmann syndrome
- agraphia, acalculia, finger agnosia, left-right disorientation
non-dominant parietal lesion
hemispatial neglect syndrome
- agnosia of contralateral side of world
hippocampal bilateral lesion
anterograde amnesia, can’t make new memories
basal ganglia lesion
tremor at rest, chorea, athetosis
subthalamic nucleus lesion
contralateral hemiballismus
mammillary body lesion
Wernicke-Korsakoff
- ataxia, confusion, nystagmus, ophthalmoplegia, memory loss, confabulation
amygdala lesion
Kluver Bucy syndrome
- diminished behavior
- caused by HSV-1 encephalitis
superior colliculus lesion
Parinaud syndrome
- paralysis of conjugate vertical gaze
- in stroke, hydrocephalus, pinealoma
reticular activating system lesion
coma
cerebellar hemisphere lesion
intention tremor, limb ataxia, loss of balance, fall toward side of lesion
cerebellar vermis lesion
truncal ataxia, dysarthria
- seen in chronic alcohol use
brain most vulnerable to ischemia
hippocampus (vulnerable hippo)
alternative to granulation tissue in brain
reactive gliosis
most common site of infarction in brain
MCA
epidural hematoma
- rupture of middle meningeal artery
- biconcave on MRI
- does not cross suture lines
subdural hematoma
- rupture of bridging veins
- cause by atrophy or trauma
- crescent shaped causing midline shift
subarachnoid hemorrhage
- rupture of berry aneurysm
- xanthochromic spinal tap
- vasospasm 4-10 days later
- nimodipine reduces vasospasm
intraparenchymal hemorrhage
- systemic hypertension
- amyloid angiopathy, vasculitis, neoplasm
- in basal ganglia and internal capsule (Charcot-Bouchard microaneurysm)
middle cerebral stroke
- contralateral paralysis of and sensory loss of upper limb and face
- aphasia in dominant (Gerstmann’s), hemineglect in non dominant
- Wernicke aphasia with right superior quadrant visual defect due to temporal lobe
anterior cerebral stroke
- contralateral paralysis and sensory loss of lower limb
lenticulo striate stroke
- affects striatum and internal capsule
- contralateral paralysis and sensory loss of whole body
- no cortical signs
- due to hyaline arteriolar sclerosis from hypertension
anterior spinal artery stroke
- causes medial medullary syndrome
- affects lateral corticospinal tract (motor in limbs), medial lemniscus (ascending dorsal columns, CN 12
- leads to contralateral paralysis, contralateral proprioception and ipsilateral hypoglossal dysfunction
posterior inferior cerebellar artery stroke
- causes lateral medullary syndrome
- affects, nucleus ambiguus (CN 9,10,11), vestibular nuclei, lateral spinothalamic tract, spinal trigeminal nucleus
- leads to dysphagia, hoarseness, no gag, vomiting, vertigo, less p/t from contralateral body and ipsilateral face
- ipsilateral horner syndrome (sympathetic fibers) and ataxia (inferior cerebellar peduncle)
anterior inferior cerebellar artery
- causes lateral pontine syndrome
- affects, facial nucleus, vestibular nucleus, spinothalamic tract, trigeminal nucleus, sympathetic fibers, cerebellar peduncles
- leads to paralysis of face, less lacrimation, salivation, taste, vomiting, less pain and temp from ispilateral
- ipsilateral horner and ataxia
basilar artery stroke
causes locked in syndrome, spares the RAS
posterior cerebral artery stroke
causes contralateral hemianopia with macular sparing
central post stroke pain syndrome
neuropathic pain due to thalamic lesions
- initial paresthesias followed in weeks to months by allodynia (ordinary stimulus cause pain)
Broca aphasia
speech nonfluent, comprehension intact, repetition impaired
- in frontal lobe
Wernicke aphasia
speech fluent, comprehension impaired, repetition impaired
- in temporal lobe
conduction aphasia
speech fluent, comprehension intact, repetition impaired
- damage to arcuate fasciculus
global aphasia
speech nonfluent, comprehension impaired, repetition impaired
- damage to all areas
transcortical motor aphasia
nonfluent speech, intact comprehension, repetition intact
- frontal lobe around Brocas
transcortical sensory aphasia
fluent speech, comprehension impaired, repetition intact
- temporal lobe near Wernickes
associations with aneurysms
ADPKD and Ehlers Danlos
- also hypertension, smoking, black
simple partial seizure vs complex partial seizure
both focal, simple = still have consciousness, complex is without consciousness
cluster headache
- unilateral
- repetitive and brief, periorbital pain with lacrimation and rhinorrhea, may have Horner
- treat with sumatriptan, prevent with verapamil
tension headache
- bilateral
- steady pain, no aura
- treat with NSAIDS, amitriptyline for chronic pain
migraine headache
- unilateral
- pulsating pain with aura
- irritation of CN V, meninges or blood vessels
- release substance P, calcitonin peptide or vasoactive peptide
treatment for trigeminal neuralgia
repetitive shooting pain
- treat with carbamazepine
akathisia
restlessness and intense urge to move
- in neuroleptic or Parkinsons
asterixis
flapping of wrists
- in hepatic encephalopathy
- Wilsons disease
- other metabolic derangements
athetosis
- slow snake-like writhing movements especially in the fingers
- in basal ganglia
chorea
- sudden jerky movements, purposeless
- in basal ganglia
- sydenham chorea in rheumatic fever
dystonia
sustained contractions
- blepharospasm, torticollis
essential tremor
- high frequency tremor with sustained posture
- worse with movements or anxiety
- caused by self medication with alcohol
hemiballismus
- sudden flapping of arm and leg
- in contralateral subthalamic nucleus (lacunar stroke
- “half of body” ballistic, contralateral lesion
intention tremor
- slow zigzag motion when pointing
- cerebellar dysfunction
myoclonus
- sudden brief uncontrolled contraction
resting tremor
- tremor at rest, alleviated by movement
- Parkinsons disease
- pill rolling tremor
Parkinsons buzz words
- pill rolling tremor
- shuffling gait
- MPTP
- loss of dopaminergic neurons in subtaintia nigra
- Lewy bodies with alpha-synuclein
Huntingtons buzzwords
- trinucleotide repeat (CAG)
- chorea, athetosis
- Caudate loses ACh and GABA
- ex vacuo ventriculomegaly
- neuronal death via NMDA-R
Alzheimer buzzwords
- Down syndrome (APP)
- ApoE2 is less risk
- Apo E4 is more risk
- APP, presenilin 1/2 = earlier forms
- less ACh
- senile plaques of beta amyloid
- neurofibrillary tangles
- intracellular tau protein (cytoskeleton)
frontotemporal dementia buzzwords
- Picks disease
- associated movement disorders
- frontotemporal lobe degeneration
- hyperphosphorylated tau (pick bodies)
- ubiquitinated TDP-43
Lewy body dementia
dementia and visual hallucinations
- Lewy bodies in cortex
Creutzfelt-Jakob disease
- rapidly progressive
- myoclonus
- sharp waves on EEG
- spongiform cortex
- prions of beta sheets resistant to proteases
risk factors for idiopathic intracranial hypertension
female, obesity, vitamin A excess, tetracycline, danazol
communicating hydrocephalus
less CSF absorption by arachnoid granulations
triad in normal pressure hydrocephalus
wacky, wet, and wobbly
noncommunicating hydrocephalus
structural blockage in ventricles
ex vacuo ventriculomegaly
looks like high CSF on imaging
- actually due to decrease brain tissue, in Alzheimer, HIV, pick, Huntington
osmotic demyelination syndrome
- also central pontine myelinolysis
- massive axonal demyelination in pontine white matter
- secondary to osmotic changes, correction of hyponatremia
correction of serum sodium
from low to high your pons will die
from high to low your brain will blood (edema and herniation)
MS buzzwords
- optic neuritis
- worse in heat
- relapsing and remitting
- young women far from equator
- scanning speech
- intention tremor
- nystagmus
- high IgG and myelin basic protein in CSF
- periventricular plaques
Guillain-Barre
- autoimmune destruction of Schwann cells
- ascending muscle weakness
- high CSF protein with normal cells
- Campylobacter (molecular mimicry)
Charcot-Marie-Tooth disease
- hereditary motor and sensory neuropathy
- poor structure and function of nerves of myelin sheath
- foot deformities, lower extremity weakness and sensory deficits
Krabbe disease
lysosomal storage disease
- galactocerebrosidase
- destruction of myelin sheath
- peripheral neuropathy, developmental delay, optic atrophy, globoid cells
metachromatic leukodystrophy
- lysosomal storage disease
- arylsulfatase A
- buildup of sulfatides
- impaired production of myelin sheath
- demyelination with ataxia and dementia
progressive multifocal leukoencephalopathy
- demyelination of CNS
- destruction of oligodendrocytes
- AIDS infection, latent JC
- usually fatal
adrenoleukodystrophy
- Xlinked
- metabolism of long chained fatty acids
- build up in nervous, adrenal, testes
- long term coma and death
Sturge-Weber syndrome (encephalotrigeminal angiomatosis) buzzwords
- anomaly of neural crest derivatives
- GNAQ gene
- port wine stain on face
- tram track calcifications
- unilateral
- retardation
- glaucoma
- epilepsy
tuberous sclerosis
- TSC1/TSC2
- hamartomas
- angiofibromas
- mitral regurg
- ash-leaf spots
- rhabdomyoma
- mental retardation
- renal angiomyolipoma
- seizures
- Shagreen patches
neurofibromatosis type 1
- mutation in NF1
- neurofibromin is negative regulator of RAS
- cafe au lait spots
- optic gliomas
- pheochromocytomas
- Lisch nodules
neurofibromatosis type 2
- mutation in NF2 (2 sides)
- bilateral acoustic schwannomas, cataracts, meningiomas, ependymomas
von Hippel-Lindau
VHL gene
- hemangioblastomas
- angiomatosis
- bilateral renal cell carcinoma
- pheochromocytoma
glioblastoma mutiforme
- butterfly glioma
- malignant
- astrocyte origin
- GFAP
- pseudopalisading border central area of necrosis
oligodendroglioma
- chicken wire capillary
- oligodendrocyte origin
- fried cell
- calcified
meningioma
- benign
- external to brain parenchyma
- arachnoid cell origin
- whorled pattern
- psammoma bodies
hemangioblastoma
- von Hippel Lindau
- blood vessel origin
- produce EPO
- thin walled capillaries
pituitary adenoma
- hyperplasia of one cells
- most common is prolactin
- bilateral hemianopia
schwannoma
- Schwann cell origin
- cerebellopontine angle
- CN 8 involvement
- bilateral in NF-2
pilocytic astrocytoma
- in kids
- posterior fossa
- benign, good prognosis
- GFAP
- Rosenthal fibers (eosinophilic corkscrews)
medulloblastoma
- in kids, malignant
- involves cerebellum and 4th ventricle
- drop metastases to spinal cord
- neuroectodermal PNET
- Homer-Wright rosettes, small blue cells
ependymoma
- in kids in 4th ventricle
- perivascular rosettes
- rod shaped blepharoplasts (basal ciliary bodies) near nucleus
crainiopharyngioma
- in kids but supratentorial
- from remnants of Rathke pouch
- calcium crystals in motor oil fluid in tumor
pinealoma
- in kids
- Parinaud syndrome (tectum compression leads to vertical gaze palsy
- precocious puberty in males
- like germ cell tumors (seminoma)
cingulate herniation
cingulate under falx cerebri, compresses anterior cerebral artery
transtentorial herniation
caudal herniation
- rupture of paramedian basilar artery
- fatal
uncal herniation
- median temporal lobe
- compresses CN III, ipsilateral PCA, contralateral crus cerebri
cerebellar tonsillar herniation
- results in coma and death
poliomyelitis and Werdnig Hoffman disease (spinal cord lesion)
- anterior horn cells
- floppy baby with fasciculations
- poliomyelitis = asymmetric
- Werdnig Hoffman = symmetric
ALS (spinal cord lesion)
- loss of cortical and spinal motor neurons
- UMN/LMN
- superoxide dismutase
- asymmetric weakness
occlusion of anterior spinal artery (spinal cord lesion)
- spares dorsal column
- UMN lesion above defect (corticospinal)
- LMN lesion at level (anterior horn)
- loss of pain and temp below (spinothalamic)
tabes dorsalis (spinal cord lesion)
- syphilis
- demyelination of dorsal columns
- Charcot joints, Argyll Roberson pupils
- Romberg sign
syringomyelia (spinal cord lesion)
- loss of anterior white commissure
- loss of crossing fibers of ST track
- loss of pain and temp in cape distribution
- seen with Chiari I
B12 deficiency (spinal cord lesion)
degeneration of…
- spinocerebellar
- lateral corticospinal tracts
- dorsal column
cauda equina (spinal cord lesion)
- radicular pain
- bladder and anal sphincter loss
- compression of nerve roots below L2
brown sequard syndrome (spinal cord lesion)
hemisection of spinal cord
- ipsilateral loss of sensation at level
- ipsilateral LMN at level
- ipsilateral UPN signs below
- ipsilateral loss of vibration and position below
- contralateral loss of pain and temp below
Friedreich ataxia
- trinucleotide repeat GAA
- impairment of mitochondria
- ataxia, falling, nystagmus, diabetes, hypertrophic cardiomyopathy
- kyphoscoliosis
