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neuro and psych


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temporal lobe abscess
causes: staph, strep, bacteroides
cavities usually surrounded by fibroblasts and new vessels
pts usually have a predisposing condition
->endocarditis, bronchiectasis
tx of OCD
TCAs (clomipramine)
SSRIs (fluoxetine)
which nerve innervates posterior half of external auditory hiatus
auricular branch of the vagus nerve
-compression can cause symptoms like fainting, coughing, gagging
selective frontal and temporal atropy in a demented patient
suggests Pick disease
severe neuronal loss and astrocytosis
pick bodies: intracytoplasmic spherules w/paired helical filaments (SILVER STAIN best)
embolization from endocarditis usually affects what part of the brain?
multiple small parietal lobe abscesses
leads to defect in spatial recognition
often mistaken for small strokes
notable SEs for lithium
hypothyroidism, nephrogenic DI, and tremors
Negri bodies
pathognomonic for Rabies encephalitis
most often in hippocampus and cerebellar cortex
histo: elongated eosinophlilic intracytoplasmic inclusions
tumors of lateral ventricle can affect which structure by direct extension
caudate nucleus [comprises part of the wall of the lateral ventricle]
Arnold-Chiari type 2
abnormally small posterior fossa
->downward displacement of cerebellar vermis and medulla thru foramen magnum
->obstruction of CSF flow leads to hydrocephalus
Arnold-Chiari type 1
more common than type 2
downward displacement of cerebellar tonsils thru foramen magnum
-> usually asymptomatic, found on autopsy
Dandy-Walker malformation
abnormally large posterior fossa
cerebellar vermis is absent and replaced by a midline cyst [looks like an expanded 4th ventricle]
brainstem nuclei are also abnormal
Glioblastoma multiforme
most agressive astrocytic tumor (type IV)
necrosis or hemorrhage on cut section
pleiomorphic tumor cells that are frequently bizarre with markedly enlarged, abnormal nuclei
adults: cerebral cortex
children: brainstem
HSV encephalitis
necrotizing, hemorrhagic acute
lower portions of cerebral cortex: temporal and base of frontal lobes [maybe b/c spreads from oropharynx]
60% of brain abscesses are related to _____ infection
middle ear infection [OM] (especially cerebellar abscesses)
most common site of obstruction resulting in hydrocephalus
aqueduct of sylvius
(connects 3rd ventricle to 4th ventricle)
normal pressure hydrocephalus
classic triad
->memory loss
->urinary incontinance
->gait abnormalities
results from intermittent increases in CSF pressure, leads to progressive damage to cerebral white matter
and dilation of the ventricles
Tx: ventricular shunt
neurotransmitter that induces REM sleep
marker to determine proliferative activity of astrocytoma

(also check mitotic activity)
superior opthalmic vein communicates directly with
cavernous sinus
->also contains CN III, IV, VI, V2 and V1, and ICA
uncal herniation
medial aspect of temporal lobe (uncus) is forced under free edge of tentorium cerebelli
often compresses oculomotor nerve (CN III)
Kernig's sign
flex patient's hip but can't extend the knee without causing pain
sign of meningeal irritation
(check for bacterial meningitis)
two lateral ventricles communicates with the 3rd ventricle thru the ______
foramen of Monroe
the _____ connects the 3rd and 4th ventricles
cerebral aqueduct

blockage results in hydrocephalus
4th ventricle communicates with the subarachnoid space through ______
three outlet foramina:
2 lateral foramina of Luschka
medial foramen of Magendie
noncommunicating hydrocephalus
obstruction within the ventricles

[congenital aqueductal stenosis]
communicating hydrocephalus
blockage within the subarachnoid space

[adhesions after meningitis]
anterior cerebral artery
paracentral lobule
->leg-foot motor/sensory

ACoA: most common site of circle of Willis aneurysm
->causes bitemporal lower quandrantanopia

medial striate arteries:
->supply anterior putamen and caudate and internal capsule
middle cerebral artery
Broca's, Wernicke's, face and arm, frontal eye field

lateral striate arteries
->'stroke' arteries. supply internal capsule, caudate, putamen, globus pallidus
vertebral artery
branch of subclavian. gives rise to anterior spinal and PICA
->PICA supplies nucleus ambiguous (CN 9,10,11) and inferior cerebellum
basilar artery
formed by two vertebral arteries

supplies base of pons (pontine arteries) and CN VI fibers
AICA suppplies lateral tegmentum, CN VII, spinal trigeminal tract of CN V, inferior cerebellum
posterior cerebral artery
branch of basilar
connects to carotid via posterior communicating artery
**major blood supply to MIDBRAIN
also thalamus, lateral/medial geniculate bodies, occipital lobe

occlusion = contralateral hemianopia with macular sparing
blood supply of internal capsule
lateral striate arteries (from MCA)

and anterior choroidal artery (arises from ICA. not part of the circle of willis)
superior sagittal sinus
receives bridging veins, and CSF via the arachnoid villi
cavernous sinus
contains CN II, IV, V1, V2, VI and post-ganglionic sympathetic fibers
also contains ICA
middle meningeal artery
branch of maxillary artery
enters thru foramen spinosum
supplies most of dura

laceration = epidural hematoma
forebrain [prosencephalon]
telecephalon -> cerebral hemispheres/lateral ventricles

diencephalon-> thalmaus/ third ventricle
midbrain [messencephalon]
mesencephalon-> midbrain/ aqueduct
hindbrain [rhombencephalon]
metencephlon-> pons, cerebellum, upper part of 4th ventricle

myelencephalon-> medulla, lower part of 4th ventricle
failure of the _____ to close results in spina bifida
posterior neuropore
failure of the _____ to close results in anencephaly
anterior neuropore
fast anterograde axonal transport
transports newly synethesized organelles and NT precursors

mediated by neurotubules and kinesin
fast retrograde transport
returns used materials from axon termina to cell body for degredation/recycling
->nerve growth factor, neurotropic viruses [HSV, rabies, polio, tetanus toxin]

mediated by neuortubules and dynein
common muscle stretch reflexes
ankle jerk: S1-> gastrocnemius
knee jerk: L2-L4-> quadriceps
biceps jerk: C5-C6-> biceps
forearm jerk: C5-C6-> brachioradialis
triceps jerk: C7-C8-> triceps
dorsal column/medial lemniscus pathway
tactile discrimination, vibration, form recognition, proprioception
1st order: dorsal root ganglia
->gracile fasciculus (lower)
->cuneate fasciculus (upper)
2nd order: dessucate at caudal medulla, form medial lemniscus-> terminates in VPL of thalamus
3rd order: VPL. project to primary somatosensory cortex (areas 3,1,2)
lateral spinothalamic tract
pain and temperature sensation
1st order: DRG at all levels
2nd: dorsal horn. decussate in ventral white commissure
3rd order: VPL. project to areas 3,1,2
lateral corticospinal tract
mediates voluntary skilled motor activity, primarily of upper limbs
*not fully myelinated til end of 2nd year (lose Babinski's sign)
arises in premotor (6) and primary motor cortex (4) and primary sensory cortex (3,1,2)
terminates contralaterally on ventral horn motor neurons

*runs in dorsal quadrant of lateral funiculus
UMN lesions
casued by transection of the corticospinal tract

result in spastic paresis with pyramidal signs [Babinski]
LMN lesions
damage to motor neurons

result in flaccid paralysis, areflexia, atrophy, fasciculations, fibrillations

ex: poliomyelitis
sensory pathway lesion
ex: tabes dorsalis [dorsal column]
loss of tactile discrimination and position and vibration sense
pain and paresthesias also
positive romberg sign: (fall over when close eyes w/feet together)
Brown-Sequard syndrome
=spinal cord hemisection

damage to:
->dorsal columns, lateral corticospinal tract, lateral spinothalamic, ventral horn
ventral spinal artery occlusion
causes infarction of anterior 2/3 of spinal cord but spares dorsal columns and horns
three branches of the trigeminal ganglion
opthalmic nerve (CN V1)
->wall of cavernous sinus, enters through superior orbital fissure
maxillary nerve (CN V2)
->wall of canverous sinus, exits thru foramen rotundum
mandibular nerve (CN V3)
-> exits thru foramen ovale
-> has sensory and motor components
ventral trigeminothalamic tract
pain and temperature sensation from face and oral cavity

3rd order neurons: VPM to brodmann's 3, 1, 2
dorsal trigeminothalamic tract
tactile discrimination and pressure sensation from face and oral cavity
input from Meissner's and Pacini's corpuscles
also project to VPM.
trigeminal reflexes
corneal reflex
jaw jerk reflex
tearing reflex
oculocardiac reflex [pressure on the globe = bradycardia]
Weber's test
unilateral conduction deafness = hears vibration more on affected side

partial nerve deafness = more on normal side
denervation of CN III muscles
ptosis (no levator palpebrae)

eye looks down and out
[unopposed action of lateral rectus and superior oblique]
the _____ is the most epileptogenic part of the cerebrum

sommer's sector is very sensitive to ischemia
bilateral destruction/removal of the cingulate gyri
causes loss of initiative and inhibition
also dulling of the emotions
memory is unaffected
often used to treat severe anxiety and depression
GABA-ergic cells
purkinje, stellate, basket, golgi cells of the cerebellar cortex

*GLYCINE is the inhibitor NT of the spinal cord. {renshaw cells}
major excitatory NT of the brain

neurons project to striatum, subthalamic nucleus, thalamus

*can be NEUROTOXIC (esp in huntington's disease)
inability to perform motor activites even with intact motor and sensory systems and normal comprehension
lesion usually in Wernicke's area
*gait apraxia is a frontal lobe sign seen with normal pressure hydrocephalus
problem with local anesthetics in inflammatory tissue
this tissue is very acidic, so anesthetic will be less effective
lidocaine becomes protonated and gives poor anesthesia
superior laryngeal nerve
internal branch provides sensory innervation to laryngeal mucosa above the vocal folds
most ischemic damage would be caused by blockage of which cerebral artery?
middle.. because it is not in the circle of willis (no available collaterals)
most frequent benign intracranial neoplasm
contains whorls of elongated cells and scattered psammoma bodies
is not invasive. main Sx are from mass effect (tends to push down)
organization of motor neurons in a spinal cord section
trunk and proximal muslces are located medially

distal muscles are lateral

extensors are anterior

flexors are posterior
type of hemorrhages that alzheimer patients are prone to
large lobar hemorrhages often in the parietal lobe

often destroy an entire cerebral hemisphere, resulting in death

**due to amyloid deposition in walls of cerebral blood vessels [amyloid angiopathy]
hemorrhage of ventral pons
is a 'locked in syndrome' (pt is aware of being trapped in own body, communicates w/eyelids)
descending corticospinal and corticobulbar fibers are interrupted
mechanism of pyridostigmine and neostigmine
carbamylate the acetylcholinesterase enzyme
[temporarily inhibits the enzyme]
internuclear opthalmoplegia
differs from lesion of oculomotor nerve b/c patient IS ABLE to converge their eyes

(is a lesion of the MLF)
occlusion of PICA
lateral medullary syndrome
->deficits in pain and temperature sensation over contralateral body [spinothalamic]
->ipsilateral dysphagia, hoarseness, diminished gag reflex [vagal, glossopharyng]
->ipsilateral horner's syn
->ipsilateral loss of pain and temp on face [spinal tract and trigeminal nucleus]
hemorrhage of internal capsule
receives blood supply from lenticulostriate arteries (which are prone to damage from uncontrolled HTN)
leads to contralateral dense hemiplegia (paralysis of arm and leg are of same intensity)

cranial nerves are also affected (facial in this case)
cell types derived from neural crest
Schwann cells, multipolar ganglion cells, pseudounipolar (spinal and CN ganglia), chromaffin cells of adrenal medulla, odontoblasts, melanocytes, cells that make pia and arachnoid
structure most affected by subfalcian herniation
cingulate gyrus (b/c subfalcian crosses the midline) which is just above the corpus callosum
location of Wernicke's area
superior temporal gyrus of the language dominant hemisphere
axons from the olfactory nerve go to _____
the pyriform cortex [the primary olfactory cortex]
the insula contains the primary _____ cortex
nucleus ambiguous
special visceral efferent fibers of X and IX
postcentral gyrus

precentral gyrus
primary sensory cortex

primary motor cortex
neurofibrillary tangles
composed of bundles of paired helical filaments twisted around each other
PHFs result from abnormal phosphorylation of tau [microtubule ass'd protein]
how does HIV gain access to the CNS?
through incoming macrophages
causes subacute inflammation of brain parenchyma ->HIV encephalitis
*presence of multinucleated giant cells is very typical
chorda tympani
branch of CN VII
controls salivation from submandibular and sublingual glands

parotid is innervated by CN IX
stage 2 sleep
more theta waves than stage 1
sleep spindles and K complexes on EEG
REM sleep
transient large amplitude potentials in occipital areas [PGO spikes = dreaming]
stage 1 sleep
= 'drowsiness'
characterized by attenuation of alpha spikes and the initial appearance of theta spikes
stage 3 and 4
high amplitude slow waves, especially delta
slow growing benign tumors, most common in the elderly
originate from dura or arachnoid mater
often cause osteoblastic rxn in overlying cranial bones
**whorls and psammoma bodies**
if present as mass lesions, may cause seizures
*superior parasagittal surface of frontal lobes is a common site of origin
->produces leg weakness
early onset/ Ts21 alzheimer's is due to
extra copy of APP (amyloid precursor protein) gene

amyloid Beta accumulates within the core of senile plaques
drug of choice in pts with status epilepticus
diazepam [valium]
->a BDZ

phenytoin is then administered for long term prevention and seizure control
LENS opacifications
retinopathy of prematurity
inappropriate proliferation of vessels in inner layer of retina
retinal damage due to glaucoma
ganglion cell and optic nerve degeneration
empty sella syndrome
pituitary radiologically appears to be absent
sella is filled w/CSF
caused by herniation of arachnoid through the diaphragm sella
causes pressure atrophy of the pituitary gland
also caused by Sheehan's
location of visual defect lesions
central scotomata: macula
ipsilateral blindness: optic n.
bitemporal hemianopia: chiasm
homonymous hemianopia: tract
upper homonymous quadrant: temporal lobe
lower " " : parietal lobe
macular sparing: occipital lobe
pilocytic astrocytoma
usually affects children
cerebellum, hypothalamus
**Rosenthal fibers
grade 1 astrocytoma
appears as cyst w/a mural nodule**
mutation of Rb on chrom 13
neuroepithelial cells that form Flexner-Wintersteiner rosettes

if familial: bilateral
rare side effect of sumatriptan
hypertensive crisis
1/2 of cases of intraparenchymal hemorrhages occur here
basal ganglia and internal capsule

[due to hypertension usually]
geniohyoid is innervated by
C1 [ansa cervicalis]

moves hyoid anteriorly to open the pharynx

C1 also innervates thyrohyoid and intra hyoids
drooping of the eyelid + mydriasis of the pupil
lesion of oculomotor nerve

(controls levator palpebrae and parasympathetic fibers of ciliary ganglion)
Wernicke-Korsakoff syndrome
thiamine deficiency, usually secondary to chronic alcohol abuse
confusion, ataxia, vestibular dysfunction, sluggish pupillary light reflexes, oculomotor dysfxn
anterograde amnesia and confabulation can occur if untreated
Parinaud's syndrome
pineal tumor that compresses superior colliculi and pretectal area of dorsal midbrain
compression of the superior colliculous causes fixed upward gaze
also can cause papilledema by compression of cerebral aqueduct
primary CNS lymphoma
Sx: seizures, headache and CN deficits
often see multicentric lesions, may involve leptomeninges
*usually a late manifestation of AIDS
medium to high grade B cell lymphoma, typically related to EBV
sequence of events for MS demyelinating plaques
acute: lymphoblastic infiltration and active digestion of myelin
2: hyperplasia of astrocytes transform plaque into gliotic area [axons preserved, but oligodendrocytes diminished]
carbonic anhydrase inhibitor
leads to reduced production of aqueous humour
*for acute treatment of narrow angle glaucoma
dorzolamide is for chronic treatment of open-angle glaucoma
danger of overdose of TCAs
fatal arrhythmias
can produce hypotension, shock, death
associate acoustic neuromas with____
neurofibromatosis type II
associate meningiomas with____
breast cancer, possibly high estrogen states
associate neurofibromas with_____
neurofibromatosis type I
rate of nerve regeneration when two cut ends have been reconnected
1 mm/day
internal capsule
thick band of myelinated fibers that project from cortex to brainstem and spinal cord
OR project from thalamus to cortex
lesions cause motor or sensory defects depending on which pathway they affect
signs/symptoms = CONTRALATERAL
three actions of TCAs
1: inhibit biogenic amine [NE and 5HT] reuptake at presynaptic neurons
2: induce sedation
3: produce central and peripheral anticholinergic effects
Binswanger disease (subcortical leukoencephalopathy)
neurological symptom ass'd with HTN
diffuse irregular loss of axons and myelin accompanied by widespread gliosis
pathology = damage via severe atherosclerosis
gag reflex
CN IX for sensory limb [unilateral]

CN X for motor limb [bilateral]

if both are lesioned, then the uvula deviates to the unaffected side when the unaffected side is tapped, and when affected side is tapped, there is no gag at all
characterized by BOTH neuronal and glial differentiation

forms grey-white masses in cerebellum of kids, and cerebral hemispheres of adults

histo: sheets of densely packed, small poorly diff'd cells
CN that lies in the tonsillar fossa
glossopharyngeal (IX)
->posterior 1/3 of toungue sensory and taste
->stylopharyngeus muscle (proximal to this point)
->general sensory info to mucosa of the pharynx

**gag reflex! [loss of this can lead to death secondary to aspiration pneumonia]
drug of choice for myoclonic seizures
valproic acid

->is very effective an non-sedating
carotid body tumor (paraganglioma)
histologically similar to pheochromocytomas

catecholamines are the primary secretions from these tumors

Deck Info