Steve Nash's Neuro Assists Flashcards
Where does Herpes labialis go dormant
Trigeminal ganglia
HSV-1
Where does Herpes genitalis go dormant
sacral ganglia
HSV-2
Where does Herpes zoster go dormant
Dorsal root or trigeminal ganglia
Which elements of the neural cytoskeleton form neurofibrillary tangles in alzheimer’s disease
Microtubules
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
Mesencephalon;
Rhombencephalon develops into
Metencephalon and myelencephalon;
Telencephalon gives rise to
Cerebral hemispheres;
Lateral ventricles
Diencephalon gives rise to
Thalamus;
Third ventricles
Mesencephalon gives rise to
Midbrain;
Aqueduct
Metencephalon gives rise to
Pons and cerebellum;
Upper part of fourth ventricle
Myelencehalon gives rise to
Medulla;
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);
oligodendroglia;
astrocytes
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
Meningocele
Meninges (but not the spinal cord) herniate through spinal canal;
normal AFP
Meningomyelocele
Meninges and spinal cord herniate through spinal canal defect
Spina bifida with myeloschisis
Spinal cord visibly seen;
increased AFP
Anencephaly
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
Holoprosencephaly
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
Lissencephaly
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
Syringomyelia
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)
Astrocyte
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
Microglia
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
Oligodendroglia
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
Tanycytes
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; Hunger; 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
Hunger;
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
Satiety;
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
Benzodiazepines
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;
Lateral=Light
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;
Medial=music
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
Cerebellum
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
Hemiballismus
Sudden, wild flailing of 1 arm with or without leg;
Contralateral subthalamic nucleus injury (e.g. lacunar infarct);
Chorea
Sudden, jerky, purposeless movements;
Lesion in the basal ganglia (think Huntington)
Athetosis
Slow, writhing movements, especially seen in fingers;
lesion to the basal ganglia (think Huntington)
Myoclonus
Sudden, brief, uncontrolled muscle contraction;
Jerks, hiccups;
Common in metabolic abnormalities such as renal and liver failure
Dystonia
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;
Dysarthria;
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)
Aphasia
Higher order inability to speak
Dysarthria
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;