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Flashcards in Steve Nash's Neuro Assists Deck (381):

Where does Herpes labialis go dormant

Trigeminal ganglia


Where does Herpes genitalis go dormant

sacral ganglia


Where does Herpes zoster go dormant

Dorsal root or trigeminal ganglia


Which elements of the neural cytoskeleton form neurofibrillary tangles in alzheimer's disease



Notochord induces what

Induces overlying ectoderm to differentiate into neuroectoderm and form the neural plate


Neural plate gives rise to the

neural tube and neural crest cells;


Notochord becomes what

Notochord becomes nucleus pulposus of the intervertebral disc in adults;


Alar plate

Dorsal spinal cord;
gives to sensory


Basal plate

Ventral spinal cord;
Gives rise to motor


Prosencephalon develops into

Telencephalon and diencephalon;


Mesencephalon develops into



Rhombencephalon develops into

Metencephalon and myelencephalon;


Telencephalon gives rise to

Cerebral hemispheres;
Lateral ventricles


Diencephalon gives rise to

Third ventricles


Mesencephalon gives rise to



Metencephalon gives rise to

Pons and cerebellum;
Upper part of fourth ventricle


Myelencehalon gives rise to

Lower part of fourth ventricle


In the brain, what does the neuroectoderm give rise to

CNS neurons;
ependymal cells (inner lining of ventricles, make CSF);


In the nervous system, what does the neural crest give rise to

PNS neurons;
Schwann cells


In the nervous system, what does the mesoderm give rise to

Microglia (like macrophages, originate from mesoderm)


Neural tube defects: when do they happen, what are the findings

neuropores fail to fuse (4th week);
Elevated alpha fetoprotein (AFP) in amniotic and maternal serum;
increased AChE in amniotic fluid confirms (fetal AChE in CSF transudates across defect into amniotic fluid)


Spina bifida occulta

Failure of bony spinal canal to close, but no structural herniation;
Dura is intact;
associated with tuft of hair or skin dimple at level of bony defect



Meninges (but not the spinal cord) herniate through spinal canal;
normal AFP



Meninges and spinal cord herniate through spinal canal defect


Spina bifida with myeloschisis

Spinal cord visibly seen;
increased AFP



Malformation of the anterior neural tube resulting in no forebrain, open calvarium (frog like appearance);
Findings: increased AFP, polyhydramnios (no swallowing);
associated with maternal diabetes type I;
maternal folate intake decreases chances



Failure of left and right hemispheres to separate;
Usually occurs during weeks 5 and 6;
complex multifactorial etiology that may be related to mutations in sonic hedgehog signaling pathway;
Moderate form has cleft lip/palate, most sever form results in cyclopia;
Associated with Patau



smooth brain with no gyri;
lack of hemisphere sulci;
severe neurologic impairment


Chiari II (arnold chiari malformation)

Significant herniation of cerebellar tonsils and vermis through foramen magnum with aquaductal stenosis and hydrocephalus;
Often presents with lumbrosacral myelomeningiocele and paralysis below the defect


Dandy Walker

Agenesis of cerebellar vermis and cystic enlargement of 4th ventricle (fills the enlarged posterior fossa);
Associated with hydrocephalus and spina bifida;


Chiari I malformation

Usually seen in adults;
less significant herniation of cerebellar tonsils into magnum foramen;
Valsalva makes worse;
Usually asymptomatic



Cystic cavity (syrinx) within the spinal cord (if central then it is called hydromyelia);
Crossing anterior spinal commissural fibers are typically damaged first leading to cape like bilateral loss of pain and temperature sensation in upper extremities;
Mostly at C8 T1 level;
Associated with Chiari 1 malformation;


Tongue development

1st and 2nd branchial arches form the anterior 2/3 (taste is CN 7 and sensation is CN V3);
3rd and 4th give rise to posterior 1/3 (taste and sensation is CN 9, very posterior taste is 10);
motor is CN12;
Muscles of the tongue are derived from occipital myotomes


Stain used for neurons

Nissl Substance (Stains RER, which is only present in dendrites and cell bodies, NOT axons)


If an axon is injured it undergoes what

Wallerian degeneration;
degeneration distal to injury and axonal retraction proximally;
allows for potential regeneration of axon if in PNS (CNS will never regenerate unless it is the olfactory nerve)



Physical support, repair, K metabolism, removal of excess neurotransmitter, foot process are component of the BBB, glycogen fuel reserve buffer;
Reactive gliosis in response to neural injury;
Astrocyte marker is GFAP;
Derived from neuroectoderm



CNS phagocytes;
derived from bone marrow bone monocytes (mesodermal origin);
not readily seen in Nissl stains;
Have small irregular nuclei and relatively little cytoplasm;
Scavenger cells of CNS;
respond to tissue damage by differentiating into large phagocytic cells;
Is an Antigen presenting cell;
Secretes free radicals;
HIV infected microglia fuse to form multi-nucleated giant cells



Myelinates neurons of the CNS;
1 oligodendroglia can myleniated around 30 to 50 nerves;
Derived from neuroectoderm;
fried egg appearance;
MS, progeressive multifocal leukoencephalopathy, and leukodystrophies attacks this cell type;


Glial cells

Supporting cells of the CNS;
capable of cell division


Schwann cells

myelinates PNS in a 1:1 ratio;
promotes axonal regeneration;
Derived from neural crest;
destroyed in Guillain-Barre;


Acoustic neuroma

type of schwannoma;
Typically located in internal acoustic meatus (CN 8);
If bilateral think NF2 (on gene 22, affecting 2 ears)


Sensory: Free nerve endings

C fibers: slow unmyelinated fibers;
A delta fibers: fast, myelinated fibers;
Located on all skin;
conveys pain and temperature


Sensory: Meissner corpuscles

Large, myelinated, and adapt quickly;
Found in glabrous (hairless) skin;
Senses dynamic, fine/light touch and position sense


Sensory: Pacinian corpuscles

Large, myelinated and adapt quickly;
Found in Deep skin layers, ligaments, and joints;
Senses vibration and pressure sensation


Sensory Merkel discs

Large, myelinated and adapt slowly;
Found in the basal epidermal layer and in hair follicles;
Sense pressure, deep static touch (e.g. shapes, edges), and position sense


What are the different layers/parts to a peripheral nerve and important info about them

Endoneurium- invests single nerve fiber layers (inflammatory infiltrate in guillain Barre syndrome);
Perineurium (permeability barrier)- surrounds a fascicle of nerve fibers, must be rejoined in microsurgery for limb reattachment;
Epineurium- dense connective tissue that surrounds entire nerve (fascicle and bleed vessels)


Ependymal cells

Line ventricles of brain;
some differentiate into choroid epithelial cells;
cilia assist in CSF circulation



Specialized type of ependymal cells;
basal cytoplasmic processes contact CNS blood;
thought to aid in blood-CSF transport


NE: where is it made, what disorders alter its levels

Made in Locus Ceruleus in pons;
increased in anxiety;
decreased in depression


Dopamine: where is it made, what disorders alter its levels

Made in ventral tegmentum and SNc (midbrain);
increased in Huntington;
decreased in Parkinson;
Decreased in Depression


5-HT: where is it made, what disorders alter its levels

Made in Raphe nucleus (pons, medulla, midbrain);
Increased in parkinson;
decreased in anxiety;
decreased in depression


ACh: where is it made, what disorders alter its levels

Made in basal nucleus of Meynert;
Increased in Parkinson;
decreased in Alzheimer;
Decreased in Huntingtons


GABA: where is it made, what disorders alter its levels

Decreased in Anxiety;
Decreased in Huntington;
Made in nucleus Accumbens


Locus ceruleus is activated by what emotion

stress and panic


Nucleus Accumbens and septal nucleus are know for being what

the reward center, pleasure, addiction, and fear


Blood-Brain Barrier: made from

Foot process of astrocytes, tight junctions in non fenestrated capillary endothelial cells, and a Basement membrane;


Blood-Brain Barrier: what crosses it

Glucose and amino acids cross slowly via carrier mediated transport;
Nonpolar/lipid soluble cross rapidly via diffusion;
Area postrema has no BBB (vomiting center, OVLT-osmotic sensing);


Function of Hypothalamus

Hypothalamus wears TAN HATS;
Thirst and water balance;
Adenohypophysis control (regulates anterior pituitary),
Neurohypophysis releases hormones produced in the hypothalamus;
Autonomic Regulation;
Temperature Control;
Sexual urges


what is the OVLT

Part of hypothalamus;
not covered by BBB;
Organum vasculosum of the lamina terminalis-senses change in osmolarity)


Area postrema responds to

responds to emetics


What nucleus makes ADH

Supraoptic nucleus


What nucleus makes oxytocin

Paraventricular nucleus


Lateral area of the hypothalamus

Destruction leads to anorexia and failure to thrive in kids;
Inhibited by leptin;
If you zap you lateral nucleus you shrink laterally


Ventromedial area of the hypothalamus

Destruction (e.g. craniopharyngioma) leads to hyperphagia;
stimulated by leptin;
If you zap your ventromedial nucleus, you grow ventrally and medially


Anterior hypothalamus

Cooling and parasympathetics;
Anterior Nucleus=Cooling off (A/C=anterior cooling)


Posterior hypothalamus

Heating, sympathetics;
Posterior nucleus=get fired up (heating and parasympathetics)


Suprachiasmatic nucleus of the hypothalamus

Circadian rhythm;
SCN releases NE on the pineal gland leading to melatonin;
SCN responds to light (or lack there of)


Rapid Eye movement in REM sleep is caused by the

PPRF paramedian Pontine Reticular Formation


Drugs that decrease REM

Alcohol, Benzodiazepines, and barbiturates all decrease REM and delta wave sleep as well;
NE also decreases REM


How do you treat enuresis

bedwetting treated with oral desmopressin acetate (DDAVP), which mimics ADH;
Preferred over imipramine due to side effects


What can treat night terrors and sleep walking



Awake (eyes open) what is the EEG look like

Beta waves (highest frequency, lowest amplitude)


What is the EEG look like in Awake stage with eyes closed

Alpha waves


Stage N1 of sleep

light sleep, theta wave


Stage N2 of sleep

Deeper sleep;
when bruxism occurs;
Sleep spindles and K complexes


Stage N3 of sleep

Deepest sleep that is non-REM;
sleepwalking, night terrors, and bedwetting occur;
delta waves (lowest frequency, highest amplitude)


REM sleep

Loss of motor tone, increased Brain O2 usage, increase and variable pulse and blood pressure;
When dreaming and penile/clitoral tumescence occur;
may serve a memory processing function;
Beta waves (live awake with eyes open stage)


Posterior pituitary

Receives hypothalamic axonal projections from supraoptic (ADH) and paraventricular (oxytocin) nuclei;


input, information, destination of the VPL of the thalamus

Input is the spinothalamic and dorsal column/medial lemniscus;
Info is pain and temp, pressure, touch, vibration and proprioception;
destination is the primary somatosensory cortex


input, information, destination of the VPM

Trigeminal and gustatory pathway;
info is Face sensation and taste;
destination is the primary somatosensory cortex;
Makeup goes on the FACE (vpM)


input, information, destination of the LGN

Input is CNII;
Info is vision;
destination is the Calcarine sulcus;


input, information, destination of the MGN

input is the Superior olive and inferior colliculus of tectum;
info is hearing;
Destination is the auditory cortex of the temporal lobe;


input, information, destination of the VL

Input is the basal ganglia and cerebellum;
Info is motor;
Destination is the Motor Cortex


Limbic system

Involved in emotion, long-term memory, olfaction, behavior modification, and autonomic nervous system function;
Structures include hippocampus, amygdala, fornix, mammillary bodies, and cingulate gyrus;
5 F's-Feeding, Fleeing, Fighting, Feeling, Sex



Aids in coordination and balance;
Control ipsilateral side (outputs go to contralateral motor cortex, then that crosses when going down the corticospinal tract)


Inputs into the Cerebellum

Contralateral cortex via the middle cerebellar peduncle;
Ipsilateral proprioceptive information via inferior cerebellar peduncle from the spinal cord (inputs nerves=climbing and mossy fibers)


Outputs from the Cerebellum

Sends info to contralateral vortex to modulate movement;
Output is the purkinje cells to the deep nuclei of the cerebellum to the contralateral cortex via the superior cerebellar peduncle;


What are the deep nuclei of the Cerebellum

Lateral to medial they are the Dentate, Emboliform, Globose, Fastigial (don't eat greasy foods);


Lateral lesions in the Cerebellum

Voluntary movement of the extremities;
when injured, you tend to fall toward injured (ipsilateral) side


Medial lesions in the cerebellum

Lesions involve midline structures (vermal cortex, fastigial nuclei) and/or the flocculonodular lobe result in truncal ataxia, nystagmus, and head tilting;
These patients also may have a wide-based gait and deficits in truncal coordination;
Usually midline lesions result in bilateral motor deficits in axial and proximal limb muscles


What does dopamine do in the basal ganglia

Binds D1 in the excitatory pathway, and to D2 in the inhibitory pathway which leads to increased motion


Parkinson Disease

Degenerative disorder of CNS associated with Lewy Bodies (composed of alpha-synuclein- intracellular eosinophilic inclusion) and loss of dopaminergic neurons (i.e. depigmentation) of the substantia nigra pars compacta


Huntington Disease

Autosomal dominant trinucleotide repeat (CAG) disorder on chromosome 4;
symptoms manifest between 20 and 40;
Choreiform movements, aggression, depression, dementia;
Decreased levels of GABA and ACh in the brain;
Neuronal death via NMDA-R binding and glutamate toxicity;
Atrophy of the caudate nuclie can be seen on imaging;
CAG=Caudate loses Ach and Gaba



Sudden, wild flailing of 1 arm with or without leg;
Contralateral subthalamic nucleus injury (e.g. lacunar infarct);



Sudden, jerky, purposeless movements;
Lesion in the basal ganglia (think Huntington)



Slow, writhing movements, especially seen in fingers;
lesion to the basal ganglia (think Huntington)



Sudden, brief, uncontrolled muscle contraction;
Jerks, hiccups;
Common in metabolic abnormalities such as renal and liver failure



Sustained, involuntary muscle contractions;
Writer's cramp;
blepharospasm (sustained eyelid twitch)


Essential tremor

Action tremor; exacerbated by holding posture/limb position;
Genetic predisposition;
Patients often self-medicated with EtOH, which decreases tremor amplitude;
Treat using beta blockers, primidone


Resting tremor

Uncontrolled movement of distal appendages (most noticeable in hands);
tremor goes away with purposeful movement;
Think Parkinson disease;


Intention tremor

Slow, zigzag motion when pointing/extending arm towards target;
Cerebellar dysfunction


Internal Capsule: what are the 3 areas and what 3 tracts go through each

Anterior Limb that carries the Frontopontine and thalamicortico fibers;
Genu which carries the Corticobulbar fibers;
Posterior limb which carries the Corticospinal and some corticobulbar tracts


Lesion to the amygdala

Kluver-Bucy Syndrome (hyperorality, hypersexuality, disinhibited behavior);
Associated with HSV-1 infection


Lesion to the Frontal lobe

Disinhibition and deficits in concentration, orientation, and judgment;
May have reemergence of primitive reflexes


Lesion to the Right parietal-temporal cortex

Spatial neglect syndrome (agnosia of the contralateral side of the world);
This is the non-dominant side in most people


Lesion to the left parietal-temporal cortex

Agraphia, acalculia, finger agnosia, and left-right disorientation;
Called Gerstmann syndrome


Lesion to the Reticular activating system

found in the midbrain;
Reduced levels of arousal and wakefullness (e.g. coma)


Lesion to the Mammilary bodies

Wernicke-Korsakoff syndrome;
Confusion, opthalmoplegia, ataxia;
memory loss (anterograde and retrograde amnesia), confabulation, personality changes;
associated with thiamine B1 deficiency, EtOH abuse;
can be precipitated by giving glucose to a B1 deficient patient;
Wernicke likes a CAN of beer (Confusion, Ataxia, Nystagmus)


Lesion to the basal ganglia

May result in tremor at rest, chorea, or athetosis;
Think Parkinson


Lesion to the Cerebellar hemispheres

Intention tremor, limb ataxia, and loss of balance;
damage to the cerebellum leads to ipsilateral deficits;
Fall toward side of lesion;
Cerebellar hemispheres are lateral and affect lateral limbs


Lesion to the cerebellar vermis

Truncal ataxia;
Vermis is medial so it affects medial structures


Lesion to the Subthalamic nucleus

Get a contralateral hemiballismus


Lesion to the bilateral hippocampus

Anterograde amnesia-inability to make new memories


Lesion to the Paramedian Pontine Reticular Formation

Eyes look away from side of lesion


Lesion to the Frontal Eye Fields

Eyes look toward the side of lesion


Lesion to the temporo-occipital association cortex

Get visual agnosia (see an object, but you can't recognize it)


Central Pontine Myelinolysis

A variant of osmotic demyelination syndrome;
Acute paralysis, dysarthria, dysphagia, diplopia, and loss of consciousness;
Can cause locked in syndrome;
Massive axonal demyelination in pontine white matter tracts secondary to osmotic forces and edema;
Usually caused by overly rapid correction of hyponatremia;
From low to high you pons will die, from high to low your brain will blow (cerebellar edema/herniation)



Higher order inability to speak



motor inability to speak


Broca aphasia

non-fluent aphasia with intact comprehension;
broca area is in the inferior frontal gyrus of frontal lobe;
Broca Broken Boca (mouth in spanish)


Wernicke aphasia

Fluent aphasia with impaired comprehension and repetition;
Wernicke area is in the superior temporal gyrus of temporal lobe;
Wernicke is Wordy by makes no sense


Global aphasia

Non-fluent with impaired comprehension;
both broca and wernicke areas affected


Conduction aphasia

Poor repetition but fluent speech and intact comprehension;
Can be caused by damage to the superior temporal gyrus and/or left supramarginal gyrus;
Can't repeat phrases


Transcortical motor aphasia

Non-fluent aphasia with good comprehension and repetition


Transcortical sensory aphasia

Poor comprehension with fluent speech and repetition


Mixed transcortical aphasia

non-fluent speech, poor comprehension, good repetition


Middle Cerebral Artery lesions can affect what areas

Motor cortex (contralateral upper limb and face paralysis);
Sensory cortex (contralateral loss of sensation of upper and lower limbs and face);
Temporal lobe (Wernicke and Broca; See aphasia if dominant side (left), See hemineglect if lesion is nondominant (right) side)


Anterior Cerebral Artery lesion can affect what areas

Motor cortex (lower limb contralateral paralysis);
Sensory Cortex (Contralateral lower limb loss of sensation)


Lenticulo-Striate Artery lesion can affect what areas

Striatum and internal capsule (contralateral hemiparesis/hemiplegia)


Anterior spinal artery lesion can affect what areas

Lateral corticospinal tract (contralateral hemiparesis of upper and lower limbs;
Medial lemniscus (decreased contralateral proprioception);
Caudal medulla/hypoglossal nerve (ipsilateral hypoglossal dysfunction and tongue deviates ipsilaterally)


Medial Medullary Syndrome

Caused by infarct of paramedian branches of the ASA and vertebral arteries;


Posterior Inferior Cerebellar Artery lesion affects what areas

Lateral Medullary (Wallenberg) syndrome
Lateral medulla;
Vestibular nuclei (vomiting, vertigo, nystagmus);
Lateral spinothalamic and spinal trigeminal nucleus (decreased pain and temp from ipsilateral face and contralateral body);
Nucleus ambiguus (dysphagia, hoarsenss, decreased gag reflex);
Sympathetic fibers (ipsilateral horners syndrome);
Inferior cerebellar peduncle (ataxia, dysmetria)


Anterior inferior Cerebellar artery lesion affects what areas

Lateral pontine syndrome;
Facial nucleus are specific to AICA;
Lateral pons, cranial nerve nuclei, vestibular nuclei, facial nucleus, spinal trigeminal nucleus, cochlear nuclei, sympathetic fibers;
Symptoms are vomiting, vertigo, nystagmus, Paralysis of the face, decreased lacrimation and salvation, decreased taste from ant. 2/3 tongue, decreased corneal reflex, decreased facial pain and temp, ipsilateral decreased hearing, ipsilateral horners ,ataxia and dysmetria


Posterior Cerebral Artery lesion affects what

Occipital cortex and visual cortex;
contralateral hemianopia with macular sparing (visual acuity is fine, but decreased visual field)


Basilar artery lesion affects what areas

Pons, medulla, lower midbrain, corticospinal and corticobulbar tracts, ocular cranial nerve nuclei, PPRF;
Symptoms are preserved consciousness and blinking with quadraplegia, loss of voluntary facial, mouth, and tongue movements (locked in syndrome where you can do vertical eye movements and blink)


Anterior Communicating artery lesion

Most common lesion in aneurysm;
can lead to stroke;
Saccular (berry) aneurysm can impinge cranial nerves;
Symptoms are visual field defects;
Lesions are typically aneurysms not strokes!


Posterior Communicating artery lesions

Common site for saccular aneurysms;
CN III palsy where eye is down and out with ptosis and pupil dilation;
Lesions are typically aneurysms not strokes!


Berry Aneurysms

Occur at bifurcations in the circle of willis;
Mostly at the junction of the Acom and ACA;
Rupture leads to subarachnoid hemorrhage (worst headache ever) or hemorrhagic stroke;
can compress optic chiasm;
Associated with ADPKD, Ehlers-Danlos, Marfan;
Risk factors are old age, HTN, smoking, being black


Charcot-Bouchard microaneurysm

Associated with chronic HTN;
affects small vessels (mostly basal ganglia and thalamus)


Central post stroke pain syndrome

Neuropathic pain due to thalamic lesions;
Initial sensation of numbness and tingling followed by weeks to months of allodynia (normal stimuli cause pain) and dysaesthesia;
occurs in 10% of stroke patients


Epidural Hematoma

Rupture of the middle meningeal artery (branch of the maxillary artery), often secondary to fracture of the temporal bone;
Lucid Interval;
Rapid expansion of blood since it is arterial leading to transtentorial herniation and CN III palsy;
CT shows lens like lesions, hyperdense blood collection that does NOT cross suture lines (Can cross falx, tentorium)


Subdural Hematoma

Snaking Subdural;
Rupture of bridging veins;
slow venous bleeding so it takes longer;
seen in elderly individuals, alcoholics, blunt trauma, shaken baby;
Can cross suture lines but cannot cross falx or tentorium


Subarachnoid hemorrhage

Rupture of an aneurysm or an AVM;
rapid time course;
Patient complains of worst headache of my life;
bloody or yellow (xanthochromic) spinal tap;
2-3 days afterward, risk of vasospasm due to blood breakdown (not visible on CT, treat with nimodipine) and rebleeding (seen on CT)


Intraparenchymal hemorrhage

AKA Hypertensive hemorrhage;
Most commonly caused by systemic HTN;
Also seen with amyloid angiopathy, vasculitis, and neoplasm;
Typically occurs in the basal ganglia and internal capsule (charcot-bouchard aneurysm of lenticulostriate vessels), but can be lobar


What is the time table of histologic events after a ischemic stroke

12-48 hours you get Red neurons;
24-72 hours you get necrosis + neutrophils;
3-5 days you get macrophages;
1-2 weeks you get reactive gliosis + vascular proliferation;
>2 weeks you get glial scars


Ischemic stroke: what areas are susceptible to damage

irreversible damage starts at 5 minutes;
most vulnerable areas are the hippocampus, neocortex, cerebellum, watershed areas;


Hemorrhagic stroke

Intracerebral bleeding, often due to HTN, anticoagulation, and cancer (abnormal vessels can bleed);
may be secondary to ischemic stroke followed by reperfusion (increased vessel fragility);
Basal ganglia are most common site of intracerebral hemorrhage


Ischemic Stroke: what is it

Acute blockage of vessels leading to disruption of blood flow causing ischemia;
results in liquefactive necrosis;


How do you treat ischemic strokes

Treatment- tPA (if within 3 to 4.5 hr of onset and no hemorrhage/risk of hemorrhage). Reduced risk with medical therapy (e.g. aspirin, clopidogrel)


What are the types of ischemic strokes

1) Thrombotic-due to a clot forming directly at the site of infarct (commonly at MCA);
2)Embolic-an embolus from another part of the body obstructs a vessel, can affect multiple vascular territories, often cardioembolic;
3)Hypoxic-due to hypoperfusion or hypoxemia, common during cardiovascular surgery, tends to affect watershed areas;


Transient ischemic attacks

Brief, reversible episode of focal neurologic dysfunction


Ventricular system: the flow of CSF

Lateral ventricle dumps into the 3rd ventricle via right and left interventricular foramina of Monro;
3rd vent. dumps into 4th vent via cerebral aqueduct of Sylvius;
4th dumps in to subarachnoid space via 2 foramina of Luschka (Lateral) and 1 foramen of Magendie=Medial;


How is CSF made and reabsorbed

Made by the ependymal cells of the choroid plexus;
reabsorbed by arachnoid granulations in the superior sagittal sinus


Communicating Hydrocephalus

decreased CSF absorption by arachnoid granulations, which can lead to increased intracranial pressure, papilledema, and herniation (e.g. arachnoid scarring post meningitis)


Normal pressure hydrocephalus

Does not result in increased subarachnoid space volume;
Expansion of ventricles distorts the fibers of the corona radiata and leads to clinical triad of urinary incontinence, ataxia, and cognitive dysfunction (wet, wobbly, and wacky);
treat with ventricle shunt


Hydrocephalus ex vacuo

Appearance of increased CSF in atrophy (Alz, advanced HIV, Huntington, Pick disease);
Intracranial pressure is normal;
triad not seen;
Apparent increase in CSF observed in imaging is actually result of decreased neural tissue due to atrophy


Noncommunicating hydrocephalus

Caused by structural blockage of CSF circulating within the ventricular system (e.g. stenosis of the aqueduct of Sylvius) leading to increased intracranial pressure leading to bilateral papilladema, nausea/vomiting, nuchal rigidity, mental status change


How many spinal nerves do we have

31 spinal nerves;
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal;
C1-C7 exit at corresponding vertebra, all others go out one vertebra below


Vertebral disc herniation

Nucleus pulposus (soft central disc) herniates though the annulus fibrosus (outer ring);
usually occurs posterolaterally at L4-L5 or L5-S1


Dorsal column sense what

sends ascending pressure, vibration, fine touch, and proprioception;


Dorsal column first order neurons

1st order neurons: sensory nerve endings to the cell bodies in the dorsal root ganglia, enters the spinal cord, ascends ipsilaterally in dorsal column;
1st synapse: ipsilateral cuneatus (upper body, arms) or gracilis (lower body, legs) in medulla


Dorsal column second and third order neurons

from ipsilateral cuneatus (upper body, arms) or gracilis (lower body, legs) it decussates in medulla then ascends contralaterally in medial lemniscus;
second synapse is in the VPL of the thalamus;
3rd order neuron goes to sensory cortex


Spinothalamic tract: senses what

Sends ascending-lateral: pain, tempurature and medial: crude touch and pressure;


Spinothalamic tract: 1st order neurons

1st order neurons are sensory nerve endings (Adelta and C fibers) to the cell body in dorsal root ganglia where it enters the spinal cord;
1 synapse is in the ipsilateral gray matter of the spinal cord (dorsal horn)


Spinothalamic tract: 2nd order neurons

from the synapse in the ipsilateral dorsal horn the 2nd order neuron decussates at the anterior white commissure and ascends contralaterally to the VPL thalamus where it synapses and a 3rd order neuron goes to the sensory cortex


Lateral corticospinal tract: sends what

Sends descending voluntary movement of contralateral limbs


Lateral corticospinal tract: first order neurons

UMN: cell body in primary motor cortex where it descends ipsilaterally (through internal capsule), most fibers decussate at caudal medulla (pyramidal decussation) where it descends contralaterally;
First synapse is in the cell body of the anterior horn in the spinal cord


Lateral corticospinal tract: second order neurons

from the anterior horn the LMN (2nd order) leaves the spinal cord and goes to the NMJ


Romberg test looks at what

unconscious proprioception;
tests the spinocerebellar and dorsal column pathways


Multiple sclerosis is destruction of what in the spinal cord

Due to demyelination;
mostly white matter of cervical region;
random and asymmetric lesions, due to demyelination;
scanning speech, intention tremor, nystagmus


Amyotrophic lateral sclerosis: is damage to what

Combined UMN and LMN deficits with NO sensory, cognitive, or oculomotor deficits;
Can be caused by defect in superoxide dismutase 1;
Commonly presents as fasciculations with eventual atrophy and weakness of hands;
RiLUzole (Lou Gerhrig) is given to decrease presynaptic glutamate release;


Complete occlusion of the anterior spinal artery damages what parts of the spinal cord

Spares the dorsal columns and lissauer tract;
Every other tract is lesioned at and below the area of the occlusion;
The upper thoracic ASA territory is a watershed area, as artery of Adamkiewicz supplies ASA below T8


Tabes dorsalis affects what

Caused by tertiary syphilis;
Results from degeneration (demyelination) of dorsal columns and roots leading to impaired sensation and proprioception and progressive sensory ataxia leading to poor coordination;
associated with Charcot joints, shooting pain, Argyll Robertson pupils;
See absent DTRs and + romberg



Syrinx expands and damages anterior white commissure of spinothalamic tract (2nd order neurons) leading to bilateral loss of pain and temp sensation (usually C8 to T1);
Seen with Chiari 1 malformations;
can expand and affect other tracts


Vitamin B12 or Vitamin E deficiency leads to problems with what parts of the spinal cord

Get subacute combined degeneration which is demyelination of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts;
see ataxic gate, paresthesia, impaired position and vibration sense



Cause by polio virus (Fecal-oral);
replicates in the oropharynx and small intestine before spreading via blood to the CNS;
Infection causes destruction of cells in the anterior horn of the spinal cord (death of LMNs);
Symptoms are LMN signs and general infection signs;
Findings: CSF with increased WBCs and slight increase of protein (no glucose change);
Virus can be found in stool or throat;


Werdnig Hoffmann Disease

AKA spinal muscular atrophy;
Congenital degeneration of the anterior horns of the spinal cord leading to LMN lesions;
Floppy baby with marked hypotonia and tongue fasciculations, starts eating then gets tired;
infantile type has median age of death of 7 months (corticobulbar tract damage leads to respiratory failure);
Autosomal recessive


Friedreich Ataxia

Autosomal recessive trinucleotide repeat disorder (GAA) on chromosome 9 in gene that encodes frataxin (iron binding protein);
leads to impairment in mitochondrial function;
degeneration of multiple spinal tracts leads to muscle weakness and loss of DTRs, vibratory sense, proprioception;
Friedreich is Fratastic (frataxin): he is your favorite FRAT brother, always STUMBLING, STAGGERING, and FALLING, but has a big heart (hypertrophic cardiomyopathy cause of death);
Present in child with kyphoscoliosis


Brown Sequard syndrome

Hemisection of spinal cord;
Ipsilateral UMN signs below level of the lesion (corticospinal damage);
Ipsilateral loss of tactile, vibration, proprioception sense 1-2 levels below lesion (dorsal column damage);
Contralateral pain and temp loss below level of lesion (spinothalamic damage);
Ipsilateral loss of all sensation at level of lesion;
Ipsilateral LMN at level of lesion;
If at level T1 will get Horners due to damage of the oculosympathetic pathway


Horner Syndrome

Sympathectomy of face;
Ptosis (slightly drooping eyelid; superior tarsal muscle);
Anhidrosis (absent sweating) and flushing of affected side;
Miosis (pupil constriction);
Associated with lesion at T1;
PAM is horny


Track the oculosympathetic pathway

starts in hypothalamus descends with 1st neuron to the lateral horn in T1 where it synapses on 2nd order;
2nd order leaves spinal cord and goes to sympathetic chain where it rises to C2 (at bifercation of common carotid) and synapses on 3rd order;
Exits at C2 and innervation of sweat tracts with the external carotid and innervation of eye tracts the internal carotid


Notable Dermatomes

C2 is back of head (skull cap) but not face;
C3 is the turtleneck;
C4 is the low collar shirt;
T4 is nipples;
T7 is the xiphoid process;
T10 is the umbilicus;
L1 is inguinal ligament;
L4 wraps lateral thigh and covers knee cap;
S2, 3, 4; erection and sensation of penile and anal zones


Clinical Reflexes

Cremaster reflex=L1, L2;
Anal wink=S3, S4


Moro reflex

Hang on for life reflex;
abduct/extend limbs when startled, and then draw together


Rooting reflex

Movement of head toward one side if cheek or mouth is stroked;
nipple seeking


Sucking reflex

sucking response when roof of mouth is touched


Palmar reflex

Curling of fingers if palm is stroked


Galant reflex

Stroking along one side of the spine while newborn is face down;
causes lateral flexion of lower body toward stimulated side


Pineal gland function

Melatonin release;
Circadian rhythms


Superior colliculi

Conjugate vertical gaze center;
Remember that your eyes are SUPERIOR to your ears


Inferior Colliculi

Remember that your eyes are SUPERIOR to your ears


Parinaud syndrome

Paralysis of conjugate vertical gaze due to lesion in superior colliculi (e.g. pinealoma)


CN III does what

Oculomotor nerve;
Eye movement;
pupillary constriction (sphincter pupillae: Edinger-Westphal nucleus, muscarinic receptors);
Eyelid opening (levator palpebrae)


Cranial nerve reflexes: Corneal reflex

Afferent: V1 ophthalmic (nasociliary branch);
Efferent: VII (temporal branch: orbicularis oculi)


Cranial nerve reflexes: Lacrimation

Afferent is the V1 (loss of reflex does not preclude emotional tears);
Efferent: VII


Cranial nerve reflexes: Jaw Jerk

Afferent is V3 (sensory- muscle spindle from masseter);
Efferent is V3 (motor-masseter)


Cranial nerve reflexes: Pupillary

Afferent is II;
Efferent is III


Cranial nerve reflexes: Gag

Afferent is IX (ipsilateral);
Efferent is X (bilateral)


CN VII innervates what muscles

Facial movement;
Orbicularis oculi (eye closing);
Stapedius of ear


What muscles doe CN IX innervate

Swallowing, Stylopharyngeus (elevates pharynx, larynx)


Nucleus Solitaris

Visceral Sensory information which is taste, baroreceptors and gut distention;
CN VII, IX, and X


Nucleus Ambiguus

Motor innervation of pharynx, larynx, and upper esophagus (e.g. swallowing, palate elevation);
CN IX, X, XI (cranial portion);


Dorsal motor nucleus

Sends autonomic (parasympathetic) fibers to heart, lungs, and upper GI;


How does this structure exit the Skull: CN I

cribiform plate


How does this structure exit the Skull: CN II

Through sphenoid bone (optic canal)


How does this structure exit the Skull: ophthalmic artery

Through sphenoid bone (optic canal)


How does this structure exit the Skull: Central retinal vein

Through sphenoid bone (optic canal)


How does this structure exit the Skull: CN III

Superior Orbital fissure of the sphenoid bone


How does this structure exit the Skull: CN IV

Superior Orbital fissure of the sphenoid bone


How does this structure exit the Skull: V1

Superior Orbital fissure of the sphenoid bone


How does this structure exit the Skull: VI

Superior Orbital fissure of the sphenoid bone


How does this structure exit the Skull: ophthalamic vein

Superior Orbital fissure of the sphenoid bone


How does this structure exit the Skull: parasympathetic fibers

Superior Orbital fissure of the sphenoid bone


How does this structure exit the Skull: CN V2

Foramen Rotundum in the sphenoid bone


How does this structure exit the Skull: CN V3

Foramen Ovale in the sphenoid bone


How does this structure exit the Skull: Middle Meningeal Artery

Foramen spinosum in the sphenoid bone


How does this structure exit the Skull: CN VII

Internal acoustic meatus


How does this structure exit the Skull: CN VIII

Internal acoustic meatus


How does this structure exit the Skull: CN IX

Jugular Foramen


How does this structure exit the Skull: CN X

Jugular Foramen


How does this structure exit the Skull: CN XI

Jugular Foramen


How does this structure exit the Skull: Jugular Vein

Jugular Foramen


How does this structure exit the Skull: CN XII

Hypoglossal Canal


How does this structure exit the Skull: Spinal roots of XI

Foramen magnum


How does this structure exit the Skull: Vertebral Arteries

Foramen Magnum


What Passes through this structure: Optic Canal

CN II, ophthalamic artery, central retinal vein


What Passes through this structure: Superior Orbital Fissure

CN III, CN IV, V1, VI, ophthalmic vein, sympathetic fibers


What Passes through this structure: Foramen Rotundum



What Passes through this structure: Foramen Ovale



What Passes through this structure: Foramen spinosum

Middle Meningeal artery


What Passes through this structure: Internal Auditory Meatus



What Passes through this structure: Jugular Foramen

CN IX, X, XI, Jugular Vein


What Passes through this structure: Hypoglossal Canal



What Passes through this structure: Foramen Magnum

Spinal roots of CN XI, Brain stem, vertebral arteries


Cavernous Sinus

A collection of venous sinuses on either side of the pituitary;
blood from eye and superficial cortex drains to the cavernous sinus and then into the internal jugular vein


Cavernous Sinus: what is it in

CN III, IV, V1, V2 and VI and postganglionic sympathetic fibers en route to the orbit all pass through the cavernous sinus;
Cavernous portion of internal carotid artery is also here;
Think of it as the nerves of eye movement plus V1 and V2


Cavernous sinus syndrome

Due to mass effect, fistula, thrombosis;
ophthalmoplegia and decreased corneal and maxillary sensation with normal visual acuity;
CN VI commonly affected


CN V motor lesion

Jaw deviates toward side of lesion due to unopposed force from the opposite pterygoid muscle


CN X lesion

Uvula deviates away from side of lesion;
weak side collapses and uvula points away


CN IX lesion

Weakness turning head to contralateral side of lesion (SCM);
Shoulder droop on side of lesion (trapezius);
The left SCM contracts to help turn the head to the right


CN XII lesion (LMN)

Tongue deviates toward side of lesion ("lick your wounds") due to weakened tongue muscles on the affected side


Bones of middle ear

Malleus, incus, and stapes


Inner ear

Snail shaped, fluid filled cochlea;
contains basilar membrane that vibrates secondary to sound waves;
Vibration transduced via specialized hair cells to the auditory nerve signaling to the brainstem;
low frequency is heard at apex near helicotrema (wide, flexible);
High frequency heard best at base of cochlea (thin, rigid)


Rinne and Weber test for Conductive hearing loss

Rinne test is abnormal (bone > air);
Weber Test localized to the affected side


Rinne and Weber test for Sensorineural hearing loss

Normal Rinne test (Air > Bone);
Weber test localizes to unaffected ear


Noise-induced hearing loss

Damage to sterocilliated cells in organ of Corti;
Loss of high frequency hearing 1st;
Sudden extremely loud noises can produce hearing loss die to tympanic membrane rupture


Facial Lesions: UMN lesion

Lesion of motor cortex or connection between cortex and facial nucleus;
Contralateral paralysis of lower face;
Forehead spared due to bilateral UMN innervation


Facial Lesions: LMN lesion

Ipsilateral paralysis of upper and lower face


Facial Lesions: Facial nerve palsy

Complete destruction of the facial nucleus itself or its branchial efferent fibers (facial nerve proper);
Peripheral ipsilateral facial paralysis (drooping smile) with inability to close eye on affected side;
Can occur idiopathically, or with lyme disease, herpes simplex, herpes zoster, sarcoidosis, tumors and diabetes;
Treatment includes corticosteroids


Mastication muscles

3 muscles Masseter, teMporals, Medial pterygoid;
1 opens the mouth-Lateral Pterygoid;
All innervated by V3;
M's Munch and Lateral Lowers



Eye too short for refractive power of cornea;
Light focused behind the retina;



Eye too long for refractive power of cornea and lens leading to the light focusing in front of retina;



Abnormal curvature of cornea resulting in different refractive power at different axes;



Decrease in focusing ability during accommodation due to sclerosis and decreased elasticity



Inflammation of anterior uvea and iris, with hypopyon (sterile pus), accompanied by conjuctival redness;
Often associated with systemic inflammatory disorders (sarcoid, RA, Juvenile idiopathic arthritis, TB, HLA-B27 PAIR disorders)



Retinal edema and necrosis leading to scar;
often viral (CMV, HSC, HZV);
associated with immunosuppression


Central retinal artery occlusion

Acute, painless, monocular vision loss;
Retina cloudy with attenuated vessels and cherry-red spot at fovea


Retinal vein occlusion

Blockage of central or branch retinal vein due to compression from nearby arterial atherosclerosis;
Retinal hemorrhage and edema in affected area


Diabetic retinopathy: pathophysiology

Non-proliferative: damaged capillaries leak blood so lipids and fluid seep into retina and you see hemorrhages and macular edema (treat with macular laser and better glucose control);
Proliferative is chronic hypoxia results in new blood vessel formation with resultant traction on retina (treat with anti-VEGF injections)



Optic disc atrophy with characteristic cupping, usually with increased intraocular pressure and progressive peripheral visual field loss


Open angle glaucoma

Associated with increased age, African American race, family history;
Painless, more common in U.S.;
Primary- Cause unclear;
Secondary- Blocked trabecular meshwork from WBC (e.g. uveitis), RBCs (vitreous hemorrhage), retinal elements (e.g. retinal detachment


Closed/Narrow angle glaucoma

Primary- enlargement or forward movement of lens against central iris (pupil margin) leads to obstruction of normal aqueous flow through pupil so fluid builds up behind iris, pushing peripheral iris against cornea and impeding flow through trabecular meshwork;
Secondary- hypoxia from retinal disease (e.g., diabetes, vein occlusion) induces vasoproliferation in iris that contracts angle;


Chronic closure of glaucoma

often asypmtomatic with damage to optic nerve and peripheral vision


Acute angle closure of glaucoma

true ophthalmic emergency;
increased IOP pushes iris forward causing angle to close abruptly;
very painful, sudden vision loss, halos around lights, rock hard eye, frontal headache;
do not give epinephrine because of its mydriatic effect



Painless, often bilateral, opacification of lens leading to decreased vision;
Risk factors are increased age, smoking, EtOH, excessive sunlight, prolonged corticosteroid use, classic galactosemia, galactokinase deficiency, diabetes (sorbital), trauma, and infections



optic disc swelling (usually bilateral) due to increased ICP;
enlarged blind spot and elevated optic disc with blurred margins seen on fundoscopic exam


CN IV damage

motor to superior oblique;
patient's eye moves upward, particularly with contralateral gaze and head tilt toward the side of the lesion (problems going down stairs, may present with compensatory head tilt in the opposite direction)



constriction, parasympathetic;
1st neuron: Edinger Westphal nucleus to ciliary ganglion via CN III;
2nd Neuron: short ciliary nerves to pupillary sphincter muscles;



Dilation, sympathetic;
1st neuron: hypothalamus to ciliospinal center of Budge (C8-T2);
2nd neuron: exit at T1 to superior cervical ganglion (travels along cervical sympathetic chain near lung apex, subclavian vessels;
3rd neuron: plexus along internal carotid, through cavernous sinus: enters orbit as long ciliary nerve to pupillary dilator muscles


Pupillary light reflex

Light in either retina travels via CN II to pretectal nucleus in midbrain that activates bilaterally the Edinger-Westphal nuclei;
Pupils contract bilaterally;
So light in one eye causes both eyes to constrict


Marcus Gunn Pupil

Afferent pupillary defect due to optic nerve damage or severe retinal injury;
decreased bilateral pupillary constriction when light is shone in affected eye relative to unaffected eye;
Tested via swinging light reflex


Damage to CN III: what areas are affected first

outer layer of CN III is parasympathetic;
Inner layer is Motor;
so vascular disease that cuts off oxygen affects motor, and compression first hurts parasympathetic (think aneurysm, uncal herniation)


Retinal detachment

separation of neurosensory layer of retina (photoreceptors layer with rods and cones) from outermost pigmented epithelium (normally shields excess light, supports retina) leading to degeneration of photoreceptors leading to vision loss;
May be secondary to retinal breaks, diabetic traction, inflammatory effusions;
Often Preceded by posterior vitreous detachment (flashes and floaters) and eventual monocular loss of vision


Age related macular degeneration

Degeneration of macula (central area of retina);
causes distortion (metamorphopsia) and eventual loss of central vision;
Dry (nonexudative, 80%)- deposition of yellowish extracellular material in and beneath Bruch membrane and retinal pigment epithelium (drusen) with gradual decrease in vision, give antioxidants and multivitamin;
Wet (exudative, 15%)- rapid loss of central vision due to bleeding secondary to choroidal neovascularization, Treat with anti-VEGF or laser


internuclear ophthalmoplegia (INO)

MLF is pair of tracts that allow for crosstalk between CN VI and CN III nuclei;
coordinates both eyes to move in same horizontal direction;
Highly myelinated;
Lesions seen in demyelination;
Lesions cause medial rectus on ipsilateral side to not tract, but eyes can converge (medial rectus is working)


Alzheimer disease: genetics

old folks and increased risk in down syndrome;
Genetics: early onset in APP (Chr 21), Presenilin-1 (Chr 14), presenilin-2 (Chr 1), late onset ApoE4 (Chr 19);
ApoE2 (Chr 19) is protective;


Histology of Alzheimer disease

Decreased ACh;
Extracellular beta amyloid core;
Amyloid beta synthesized by cleaving amyloid precursor protein (APP on Chr 21);
Neurofibrillary tangles are intracellular hyperphosphorylated tau protein = insoluble cytoskeletal elements, and amount correlates to degree of dementia (worst in hippocampus)'
May see amyloid angiopathy which leads to intracranial hemorrhages (parietal lobe is most common)


Frontotemporal dementia

Picks disease;
dementia, aphasia, parkinsonian aspects;
change in personality;
Spares parietal lobe and posterior 2/3 of superior temporal gyrus;
Pick bodies are spherical tau protein aggregates;
Frontotemporal atrophy leading to disinhibition, impaired judgement and personality changes


Lewy body dementia

Initially dementia and visual hallucinatinos followed by parkinsonian features;
Alpha-Synuclein defect;
increased ubiquitin is also present


Creutzfeldt-Jakob Disease

Rapidly progressive (weeks to months) dementia with myoclonus ("startle myoclonus");
Spongiform cortex;
Prions (PrPc transform into PrPsc sheet (beta pleated sheets that are resistant to proteases) AKA 14-3-3 protein;
EEG shows recurrent bursts of biphasic and triphasic periodic sharp wave complexes


Multiple Sclerosis

Autoimmune inflammation and demyelination of CNS (brain and spinal cord);
Patients can present with optic neuritis (sudden loss of vision resulting in Marcus Gunn pupils) internuclear ophthalmoplegia, hemiparesis, hemisensory symptoms, or bladder/bowel incontinence;
Relapsing and remitting course;
mostly women in their 20s and 30s, most white;


Classic triad of MS

Charcot classic triad of MS;
1) Scanning speech;
2) Intention tremor;
3) Nystagmus


Multiple Sclerosis: Findings

Increased protein (IgG) in CSF;
oligoclonal bands are diagnostic;
MRI is gold standard;
Periventricular plaques (areas of oligodendrocyte loss and reactive gliosis) with destruction of axons;
Multiple white matter lesions separated in space and time


Multiple Sclerosis: Treatment

beta-interferon, immunosuppresion, natalizumab;
Symptomatic treatment for neurogenic bladder (catheterization, muscarinic antagonists), spasticity (baclofen, GABA receptor agonist), pain (opioids)


Acute inflammatory demyelinating polyradiculopathy

most common variant of Guillain-Barre syndrome;
autoimmune condition that destroys Schwann cells leading to inflammation and demyelination of peripheral nerves and motor fibers;
Results in symmetric ascending muscle weakness/paralysis beginning in lower extremities;
Facial paralysis in 50% of cases;
Autonomic function may be severely affected (e.g. cardiac irregularities, HTN, or hypotension);
Almost all patients survive;
the majority recover completely after weeks to months;


Acute inflammatory demyelinating polyradiculopathy Findings:

increased CSF protein with normal cell count (albuminocytologic dissociation);
increased protein leads to papilledema


Acute inflammatory demyelinating polyradiculopathy: associated with what

Associated with infections (campylobacter jejuni and CMV) leads to autoimmune attack of peripheral myelin due to molecular mimicry, inoculations, and stress, but no definitive link to pathogens;


Acute inflammatory demyelinating polyradiculopathy: treatment

Treatments are respiratory support, plasmapheresis, IV immune globulins


Progressive multifocal leukoencephalopathy

demyelination of CNS due due to destruction of oligodendrocytes;
associated with HC virus;
seen in 2-4% of AIDS patients (reactivation of latent viral infection);
Rapidly progressive, usually fatal;
increased risk associated with natalizumab


Acute disseminated (postinfectious) encephalomyelitis

Multifocal perivenular inflammation and demyelination after infection (commonly measles or VZV) or certain vaccinations (e.g. rabies, smallpox);
MRI shows inflamed white matter of CNS;
treat with high dose IV corticosteroids


Metachromatic leukodystrophy

autosomal recessive lysosomal storage disease, most common due to arylsulfatase A deficiency;
buildup of sulfatides leads to impaired production of myelin sheath;
findings are central and peripheral demyelinatino with ataxia, dementia;
no treatment


Charcot-Marie-Tooth disease

also known as hereditary motor and sensory neuropathy (HMSN);
group of progressive hereditary nerve disorders related to the defective production of proteins involved in the structure and function of peripheral nerves or the myelin sheath;
typically autosomal dominant inheritance pattern and associated with scoliosis and foot deformities (high or flat arches)


Krabbe disease

autosomal recessive lysosomal storage disease due to deficiency of galactocerebrosidase;
Buildup of galactocerebroside and psychosine destroys myelin sheath;
findings are peripheral neuropathy, developmental delay, optic atrophy, globoid cells



X-linked genetic disorder typically affecting males;
Disrupts metabolism of very-long fatty acids leading to excessive buildup in nervous system, adrenal gland, and testes;
progressive disease that can lead to long-term coma/death and adrenal gland crisis


Partial (focal) seizures

Affect 1 area of the brain;
most commonly originate in medial temporal lobe;
often preceded by seizure aura;
can secondarily generalize;
Types: 1) simple partial (consciousness intact)-motor, sensory, autonomic, psychic 2) complex partial (impaired consciousness)


Generalized seizures

Absence (petit mal)- 3Hz, no postictal confusion, blank stare, no muscle tone loss;
Myoclonic-quick, repetitive jerks;
Tonic-clonic (grand mal)-alternating stiffening and movement;
Atonic-"drop" seizures (falls to floor) and mistaken fainting


Cluster headaches

last 15 minutes to 3 hrs;
Repetitive brief headaches, excruciating periorbital pain with lacrimation and rhinorrhea, may induce Horner syndrome, more common in males;
Treat with inhaled O2 and sumatriptan


Tension headache

bilateral and constant;
>30 min (4-6 hour);
Steady pain, no photophobia, or phonophobia, no aura;
treat with analgesics, NSAIDs, acetaminophen, amitriptyline for chronic pain



lasts 4-72 hrs;
Pulsating pain with nausea, photophobia, or phonophobia, may have aura, due to irritation of CN V, meninges, or blood vessels (release of substance P, CGRP, vasoactive peptides);
Treat active migraine with triptans, NSAIDs, and prophylactic with propranolol, topiramate, Ca channel blockers, amitriptyline


Peripheral Vertigo

more common;
inner ear etiology (e.g. semicircular canal debris, vestibular nerve infection, Meniere disease);
positional testing leads to delayed horizontal nystagmus


Central vertigo

Brain stem or cerebellar lesion (e.g. stroke affecting vestibular nuclei or posterior fossa tumor);
Findings with directional change of nystagmus, skew deviation, diplopia, dysmetria;
Positional testing leading to immediate nystagmus in any direction; may change directions;
focal neurological findings


Sturge-Weber Syndrome

Congenital, non-inherited (somatic), developmental anomaly of neural crest derivatives (mesoderm/ectoderm) due to activating mutation of GNAQ gene;
Affects small (capillary-sized) blood vessels leading to port-wine stain of the face (non-neoplastic "birthmark" in CN V1/V2 distribution);
ipsilateral leptomeningeal angioma leads to seizures/epilepsy;
intellectual disability;
and episcleral hemangioma leading to increased IOP leading to early onset glaucoma;


Tuberous Sclerosis:

HAMARTOMAS: Hamartomas in CNS and skin;
Mitral regurgitation;
Ash-leaf spots;
cardiac Rhabdomyoma;
Tuberous sclerosis;
autosomal dOminant;
Mental retardation;
renal Angiomyolipoma;
Seizures and Shagreen patches;
increased incidence of subependymal astrocytomas and ungual fibromas


Neurofibromatosis type 1 (von Recklinghausen disease)

Cafe-au-lait spots, Lisch nodules (pigmented iris hamartomas), neurofibromas in skin, optic gliomas, pheochromocytomas;
mutated NF1 tumor suppressor gene (neurofibromas, a negative regulator of Ras) on chromosome 17;
skin tumors of NF-1 are derived from neural crest cells


von-hippel-Lindau disease

VHL= chromosome 3;
Cavernous hemangiomas in skin, mucosa, organs;
bilateral renall cell carcinomas;
hemangioblastoma (high vascularity with hyperchromatic nuclei) in retina, brain stem, cerbellum, and pheochromocytomas;
autosomal dominant;
mutated VHL tumor suppressor gene on chromosome 3, which results in constitutive expression of HIF (transcription factor) and activation of angiogenic growth factors


Astrocytoma or gliobastoma multiforme

Adult tumor;
Common in adult, highly malignant primary brain tumor ~1 year median survival;
found in cerebral hemispheres;
can cross corpus callosum (butterfly glioma);
stain astrocytes for GFAP;
Pseudopalisading pleomorphic tumor cells-border central areas of necrosis and hemorrhage



Adult tumor;
Most common benign, second most common brain tumor;
most often occurs in convexities of hemispheres (near surface of brain) and parasagittal region;
arises from arachnoid cells, is extra-axial (external to brain parenchyma), and may have a dural attachment (tail);
often asymptomatic;
may present with seizures or focal neurological signs;
resection and/or radiosurgery;
spindle cells concentrically arranged in a whorled pattern;
psammoma bodies (laminated calcifications);
has estrogen receptors and can grow during pregnancy;



adult tumor;
most often cerebellar;
associated with von hippel-lindau syndrome when found with retinal angiomas;
can produce erythropoietin leading to secondary polycythemia;
Closely arranged, thin-walled capillaries with minimal interleaving parenchyma



Adult tumor;
usually found at cerebellopontine angle;
schwann cell origin;
s-100 positive;
often localized to CN VIII leading to acoustic schwannoma (aka acoustic neuroma);
resectable or treated with stereotactic radiosurgery;
bilateral acoustic schwannomas found in NF-2;



Adult, relatively rare, slow growing;
most often in frontal lobes;
chicken-wire capillary pattern;
oligodendrocytes=fried egg cells (round nuclei with clear cytoplasm);
often calcified in oligodendroglioma;
surgically remove but may return


Pituitary adenoma

Adult cancer
most commonly prolactinoma;
bitemporal hemianopia due to pressure on optic chiasm;
hyper or hypo pituitarism are sequelae;


Pilocytic astrocytoma

usually well circumscribed;
Children, most often found in posterior fossa (e.g. cerebellum);
Cystic and solid on gross exam;
may be supratentorial;
Rosenthal fibers-eosinophilic, corkscrew fibers;
benign, good prognosis



highly malignant childhood cerbellar tumor;
a form of primitive neuroectodermal tumor;
can compress 4th ventricle, causing hydrocephalus;
can send "drop metastases" to spinal cord;
Homer-Wright rosettes;
solid on gross exam;
small blue cells on histology



Childhood Ependymal cell tumors most commonly found in 4th ventricle;
can cause hydrocephalus;
poor prognosis;
characteristic perivascular rosettes;
rod-shaped blepharoplasts (basal ciliary bodies) found near nucleus



Benign childhood tumor, may be confused with pituitary adenoma (both can cause bitemporal hemianopia);
most common childhood supratentorial tumor;
derived from remnants of Rathke pouch;
Calcification is common (tooth enamel like)


Effect on glaucoma: epinephrine

alpha agonist;
decrease aqueous humor synthesis via vasoconstriction;
Side effects are mydriasis, do not use in closed angle glaucoma


Effect on glaucoma: Brimonidine

Alpha 2 agonist;
decrease aqueous humor synthesis;
side effects are blurry vision, ocular hyperemia, foreign body sensation, ocular allergic reactions, ocular pruritus


Effect on glaucoma: timolog, betaxolol, carteolol

beta blockers;
decrease aqueous humor synthesis;
side effects are no pupillary or vision changes


Effect on glaucoma: acetazolamide

Decrease aqueous humor synthesis via inhibition of carbonic anhydrase;
Side effects are no pupillary or vision changes


Effect on glaucoma: direct and indirect cholinomimetics

direct-pilocarpine, carbachol;
indirect-physostigmine and echothiophate;
increase outflow of aqueous humor via contraction of ciliary muscle and opening of trabecular meshwork;
Use pilocarpine in emergencies-very effective at opening meshwork into canal of Schlemm;
Side effects are miosis and cyclospasm (contraction of ciliary muscles)


Effect on glaucoma: Latanoprost (PGF2alpha)

Increased outflow of aqueous humor;
Side effect of darkening color of iris (browning)


Opioid analgesics: drug names

morphine, fentanyl, codeine, loperamide, methadone, meperidine, dextromethorphan, diphenoxylate;


Opioid analgesics: mechanism

act as agonists at opioid receptors (mu= morphine, delta= enkephalin, kappa= dynorphin) to modulate synaptic transmission- open K+ channels, close Ca2+ channels leading to decrease synaptic transmission;
Inhibit release of ACh, NE, 5-HT, glutamate, substance P


Opioid analgesics: Clinical use

Pain, cough suppression (dextromethorphan), diarrhea (loperamide and diphenoxylate), acute pulmonary edema, maintenance programs for heroin addicts (methadone)


Opioid analgesics: Toxicity

Addiction, respiratory depression, constipation, miosis (pinpoint pupils), additive CNS depression with other drugs;
Tolerance does not develop to miosis and constipation;
toxicity treated with naloxone or naltrexone (opioid receptor antagonist)



Mechanism: Mu-opioid receptor partial agonist and kappa-opioid receptor agonist, produces analgesia;
Clinical use: severe pain (migraine, labor, etc.), causes less respiratory depression than full opioid agonists;
Toxicity: can cause opioid withdrawal symptoms if patient is also taking full opioid agonist (competition for opioid receptors), overdose not easily reversed with naloxone



Mechanism: very weak opioid agonist, also inhibits serotonin and NE reuptake (works on multiple neurotransmitters- "tram-it all" in with tramadol);
Used in chronic pain;
Toxicity: similar to opioids, decreases seizure threshold, serotonin syndrome



Used for generalized absence seizures;
mechanism- blocks thalamic T type Ca2+ channels;
side effects of GI, fatigue, headache, urticaria, steven-johnson, EFGHIJ (ethosuximide causes Fatigue, Gi distress, Headache, Itching, and steven Johnson);
SUX to have Silent Seizures



Names: diazepam, lorazepam;
used for status epilepticus;
mechanism: increased GABA-a action (increases frequency of Cl- channel opening);
Side effects: sedation, tolerance, dependence, respiratory depression;
also used for eclampsia seizure after MgSO4



Used for simple, complex, tonic-clonic, status epilepticus;
increased Na+ channel inactivation;
zero-order kinetics;
Side effects of nystagmus, diplopia, ataxia, sedation, gingival hyperplasia, hirsutism, peripheral neuropathy, megaloblastic anemia, teratogenesis (fetal hydantoin syndrome) SLE-like syndrome, induction of cyp P-450, lymphadenopathy, Steven Johnson, osteopenia



Used for simple, complex, and tonic-clonic;
increased Na+ channel inactivation;
Side effects-Diplopia, ataxia, blood dyscrasias (agranulocytosis, aplastic anemia), liver toxicity, teratogenesis, induction of cyp P450, SIADH, steven johnson;
1st line for trigeminal neuralgia


Valproic acid

Used for simple, complex, tonic-clonic, and absence seizures;
Increased Na+ channel inactivation, increased GABA concentration by inhibiting GABA transaminase;
Side effects are GI, distress, rare but fatal, hepatotoxicity (measure LFTs), neural tube defects in fetus (spina bifida), tremor, weight gain, contraindicated in pregnancy;
Also used for myoclonic seizures, bipolar disorder



Simple, Complex, tonic-clonic seizures;
Primarily inhibits high voltage-activated Ca2+ channels, designed as GABA analog;
side effects sedation and ataxia;
Also used for peripheral neuropathy, postherpetic neuralgia, migraine prophylaxis, bipolar disorder



used for simple, complex, tonic-clonic seizures;
increased GABAa action (increases the duration of opening Cl channel)



For simple, complex and tonic clonic;
blocks Na+ channels, increased Gaba action;
Side effects are Sedation, mental dulling, kidney stones, weight loss;
Also used for migraine prevention



For simple, complex, tonic-clonic, absence;
blocks voltage-gated Na channels;
Side effects are steven johnson (titrate slowly)



For simple, complex, and tonic clonic;
Mechanism is unknown, may modulate GABA and glutamate release



for simple, complex seizures;
increases GABA by inhibiting re-uptake



Simple and complex seizures;
Increase GABA by irreversibly inhibiting GABA transaminase



Names: phenobarbital, pentobarbital, thiopental, secobarbital;
Mechanism: facilitate GABAa action by increasing duration of Cl- channel opening, thus decrease neuron firing;
Contraindicated in porphyria;
Used for: sedative for anxiety, seizures, insomnia, induction of anesthesia (thiopental);
Toxicity: respiratory and cardiovascular depression (Can be fatal); CNS depression (can be exacerbated by EtOH use), dependence, drug interactions (induces cyp P-450), overdose treatment is supportive (assist respiration and maintain BP)


Benzodiazepines: names

Diazepam, lorazepam, triazolam, temazepam, oxazepam, midazolam, chlordiazepoxide, alprazolam


Benzodiazepines: mechanism

Facilitate GABAa action by increased frequency of Cl- channel opening;
decrease REM sleep;
most have long half-lives and active metabolites (exceptions: triazolam, oxazepam, and midazolam are short acting leading to higher addictive potential)


Benzodiazepines: Uses

Anxiety, spasticity, status epilepticus (lorazepam and diazepam), detoxification (especially alcohol withdrawal-DTs), night terrors, sleepwalking, general anesthetic (amnesia, muscle relaxation), hypnotic (insomnia)


Benzodiazepines: toxicity

Dependence, additive CNS depression effects with alcohol;
less risk of respiratory depression and coma than with barbiturates;
treat overdose with flumazenil (competitive antagonist at GABA benzodiazepine receptor)


Benzo, barbs, and EtOH all bind what

bind the GABAa receptor, which is a ligand-gated Cl- channel


Nonbenzodiazepine hypnotics: names

Zolpidem (ambien), Zaleplon, esZopiclone (ZZZs put you to sleep);


Nonbenzodiazepine hypnotics: mechanism

act via the BZ1 subtype of the GABA receptor


Nonbenzodiazepine hypnotics: Clinical use



Nonbenzodiazepine hypnotics: Toxicity

ataxia, headaches, confusion;
short duration because of rapid metabolism by liver enzymes;
unlike older sedative-hypnotics, cause only modest day after psychomotor depression and few amnestic effecs;
decreased dependence risk compared to benzodiazepines


Nonbenzodiazepine hypnotics: treat toxicity with

Effects reversed by flumazenil


Anesthetics-general principles

CNS drugs must be lipid soluble (cross BBB) or be actively transported;
Drugs with decreased solubility in blood=rapid induction and recovery times;
drugs with increase solubility= increased potency= 1/MAC;


what is the minimal alveolar concentration

(of inhaled anesthetic) required to prevent 50% of subjects from moving in response to noxious stimulus (e.g. skin incision)


inhaled anesthetics: names

halothane, enflurance, isoflurane, sevoflurane, methoxyflurane, nitrous oxide


inhaled anesthetics: effects

Myocardial depression, respiratory depression, nausea/emesis, increased cerebral blood flow (decrease cerebral metabolic demand)


inhaled anesthetics: toxicity

Hepatotoxicity (halothane), nephrotoxicity (methoxyflurane), proconvulsant (enflurane), expansion of trapped gas in a body cavity (nitrous oxide);
can cause malignant hyperthermia


Malignant hyperthermia

rare, life-threatening hereditary condition in which inhaled anesthetics (except nitrous oxide) and succinylcholine induce fever and severe muscle contractions;
treat with dantrolene


Barbiturates: intravenous anesthetics

Thiopental-high potency, high lipid solubility, rapid entry into brain;
used for induction of anesthesia and short surgical procedures;
effect terminated by rapid redistribution into tissue (i.e. skeletal muscle) and fat;
decreased cerebral blood flow


Benzodiazepines: intravenous anesthetics

Midazolam most common drug used for endoscopy;
used adjunctively with gaseous anesthetics and narcotics;
may cause severe postoperative respiratory depression, decreased BP, and anterograde amnesia;
treat overdose with flumazenil


Arylcyclohexylamines (ketamine)

PCP analogs that act as dissociative anesthetics;
block NMDA receptors;
cardiovascular stimulants;
cause disorietnation, hallucinations, and bad dreams;
increase cerebral blood flow;


Opioids: intravenous anesthetics

Morphine, fentanyl used with other CNS depressants during general anesthesia


Propofol: intravenous anesthetics

Used for sedation in ICU, rapid anesthesia induction, and short procedures;
less postoperative nausea than thiopental;
potentiates GABAa


Local anesthetics: names

Esters (procaine, cocaine, tetracaine);
Amides (Lidocaine, mepivacaine, bupivacaine, (amides have 2 I's))


Local anesthetics: mechanism

Block Na channels by binding to specific receptors on inner portion of channel;
preferentially bind to activated Na channels, so most effective in rapidly firing neuorns;
Tertiary amine local anesthetics penetrate membrane in uncharged form, then bind to ion channels as charged form


Local anesthetics: order of nerves they block

small diameter blocked before big;
myelinated fibers blocked before unmyelinated fibers;
overall, size matters more than myelination;
Lose 1)pain then 2) temperature then 3) touch 4) pressure


Local anesthetics: Toxicity

CNS excitation, severe cardiovascular toxicity (bupivacaine), HTN, hypotension, and arrhythmias (cocaine)


Neuromuscular blocking drugs: depolarizing

Succinylcholine- strong ACh receptor agonist;
produces sustained depolarization and prevents muscle contraction;
reversal of blockade: Phase 1- (prolonged depolarization)-no antidote. Block potentiated by cholinesterase inhibitors;
Phase 2- (repolarized but blocked, ACh receptors are available, but desensitized)-antidote consists of cholinesterase inhibitors;
Complication include hypercalcemia, hyperkalemia, and malignant hyperthermia


Neuromuscular blocking drugs: Nondepolarizing

Tubocurarine, atracurium, mivacurium, pancuronium, vecuronium, rocuronium- competitive antagonists-compete with ACh for receptors;
Reversal of blockade-neostigmine (must be given with atropine to prevent muscarinic effects such as bradycardia), edrophonium, and other cholinesterase inhibitors



Prevents the release of Calcium from the sarcoplasmic reticulum of skeletal muscle;
Uses: used to treat malignant hyperthermia and neuroleptic malignant syndrome (a toxicity of antipsychotic drugs)


Parkinson disease drugs: dopamine agonists

Bromocriptine (ergot), pramipexole, ropinirole (non-ergot);
non-ergots are preferred;


Parkinson disease drugs: increased dopamine

Amantadine (may increase dopamine release);
also used as an antiviral against influenza A and rubella;
L-dopa/Carbidopa (converted to dopamine in CNS)


Parkinson disease drugs: Prevent dopamine breakdown

Selegiline (selective MAO type B inhibitor);
entacapone, tolcapone (COMT inhibitors- prevent L-dopa degradation leading to increased dopamine availability)


Parkinson disease drugs: curb excess cholinergic activity

Benztropine (antimuscarinic; improves tremor and rigidity but has little effect on bradykinesia);
Park your Benz


L-dopa(levodopa)/carbidopa: Mechanism

increased level of dopamine in brain;
unlike dopamine, L-dopa can cross BBB and is converted by dope decarboxylase in the CNS to dopamine;
carbidopa, an peripheral decarboxylase inhibitor, is given with L-dopa to increased the bioavailability of L-dopa in the brain and to limit peripheral side effects;


L-dopa(levodopa)/carbidopa: Clinical use

Parkinson disease


L-dopa(levodopa)/carbidopa: toxicity

Arrhythmias form increased peripheral formation of catecholamines;
long-term use can lead to dyskinesia following administration ("on/off" phenomenon), akinesia between doses



Mechanism: selectively inhibits MAO-B, which preferentially metabolized dopamine over NE and 5-HT, thereby increased the availability of dopamine;
Clinic use: adjunctive agent to L-Dopa in treatment of Parkinson disease;
Toxicity: may enhance adverse effects of L-dopa



Alzheimer drug;
Mechanism: NMDA receptor antagonists, helps prevents excitotoxicity (mediated by Ca2+);
Toxicity: dizziness, confusion, hallucinations


Donepexil, galantamine, rivastigmine

Alzheimer drugs;
Mechanism: AChE inhibitors;
Toxicity: nausea, dizziness, insomnia


Neurotransmitter changes in Huntington disease

decreased GABA, Decreased ACh, increased dopamine


Medications for Huntington disease

Tetrabenazine and reserpine- inhibit vesicular monoamine transporter (VMAT), limit dopamine vesicle packaging and release;
Haloperidol- dopamine receptor antagonist



Mechanism: 5-HT(1B/1D) agonist;
inhibits trigeminal nerve activation, prevents vasoactive peptide release, induces vasoconstriction;
half life