Download Chapter 14 Brainstem III: Internal Structures and Vascular

Chapter 14 Brainstem III: Internal
Structures and Vascular Supply
Chenjie Xia
Wednesday, Oct. 20, 2010
Orientation First
Brainstem X-sections Review
Rostral Midbrain
Superior
colliculus
Cerebral
aqueduct
Oculomotor
nucleus (CNIII)
Reticular
formation
Red
nucleus
Basis
pedunculi
Substantia
nigra
Caudal Midbrain
Inferior
colliculus
Cerebral
aqueduct
Trochlear
nucleus
Superior cerebellar
peduncle and
decussation
Rostral to mid-pons
Fourth ventricle
Middle cerebellar
peduncle
Corticospinal,
corticobulbar,
corticopontine fibers
Rostral Medulla
Inferior
cerebellar
penduncle
Inferior olivary
nucleus
Medial
lemniscus
Pyramid
(corticospinal tract)
Cervicomedullary junction
Gracile nucleus
and fascicle
Pyramidal
decussation
Cuneate nucleus
and fascicle
Anterolateral
system
Brainstem Vasculature Review
Posterior Circulation Arteries
Arterial Territories
Penetrators & Circumferentials
Neuro-Jeopardy!!!
Brainstem
vascular supply
More brainstem
vascular supply
Brainstem
Internal
Structures
Miscellaneous
100
100
100
100
200
200
200
200
300
300
300
300
400
400
400
400
500
500
500
500
Brainstem Internal Structures 100
• Which of the following lesions can cause
coma?
– 1) Unilateral cortical lesion
– 2) Bilateral cortical lesions
– 3) Unilateral thalamic lesion
– 4) Bilateral thalamic lesions
– 5) Midbrain tegmentum
– 6) Ventral pons
Brainstem Internal Structures 100
• Which of the following lesions can cause
coma?
– 1) Unilateral cortical lesion
– 2) Bilateral cortical lesions
– 3) Unilateral thalamic lesion
– 4) Bilateral thalamic lesions
– 5) Midbrain tegmentum
– 6) Ventral pons
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Brainstem Internal Structures 200
• Which syndrome
would a lesion in
this area cause?
Brainstem Internal Structures 200
• “Locked-in syndrome”
– Lesion of ventral pons
– Disruption of bilateral corticospinal,
corticobulbar tracts, i.e. unable to move
– Sensory and RAS preserved, i.e. conscious
and able to feel
– Oculomotor nucleus (midbrain tegmentum)
preserved, i.e. able to do vertical eye
movements and eyelid elevation
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Brainstem Internal Structures 300
• Name the 2 main functions of the RF
Brainstem Internal Structures 300
• 1) Maintain alert,
conscious state
– Rostral RF
– Continuous with certain
diencephalic nuclei
• 2) Mediate motor, reflex
and autonomic functions
– Caudal RF
– Continuous with the
intermediate zone of the
spinal cord
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Brainstem Internal Structures 400
What respiratory
pattern results
from a lesion in
these areas?
Brainstem Internal Structures 400
1)
Cheyne-Stokes
breathing
2)
Apneustic
breathing
3)
Ataxic
breathing or
respiratory
arrest
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Brainstem Internal Structures 500
• Describe the components of the GuillainMollaret’s triangle
• Lesion in this triangle causes which
syndrome?
Brainstem Internal Structures 500
• Palatal myoclonus
Brainstem Internal Structures 500
• BONUS: How can you distinguish
symptomatic from essential palatal
myoclonus?
Brainstem Internal Structures 500
Essential Palatal Myoclonus
Symptomatic Palatal Myoclonus
25% of cases
Most cases
No lesions
Lesion in Mollaret triangle
Presence of ocular abnormalities, facial
asymmetry, hemiparesis, etc
Abnormality on neuroimaging (e.g. olivary
nucleus hypertrophy)
Audible click: tensor veli palatini inserts in
Eustachian tube
No audible click: levator veli palatinim
Myoclonus and click disappears in sleep
Myoclonus persist during sleep
Can be transiently aborted by patient,
certain neck postures, mouth opening
Cannot be aborted
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Miscellaneous 100
• Acetylcholine
• Locus ceruleus
• Dopamine
• Nucleus basalis of Meynert
• Histamine
• Raphe nucleus
• Norepineprhine
• Substantia nigra
• Serotonin
• Tuberomammillary nucleus
Miscellaneous 100
• Acetylcholine
• Locus ceruleus
• Dopamine
• Nucleus basalis of Meynert
• Histamine
• Raphe nucleus
• Noradrenaline
• Substantia nigra
• Serotonin
• Tuberomammillary nucleus
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Miscellaneous 200
• Which main NT is involved in Parkinson’s
disease?
• Can you name the 3 pathways involving
this NT? (which one is most prominently
involved in PD?)
Miscellaneous 200
Miscellaneous 200
• Parkinson’s disease:
– Deficiency of DA in SN pars compacta
– Affecting the nigrostriatal pathway, i.e.
projection of DA neurons from the SN 
striatum
• 2 other pathways
– Mesolimbic pathway: positive Sx of
schizophrenia
– Mesocortical pathway: cognitive deficits,
negative Sx of schizophrenia
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Miscellaneous 300
Miscellaneous 300
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Miscellaneous 400
• A decrease in hypocretins / orexins cause
which clinical syndrome?
• Name the 4 classic findings of this
syndrome.
Miscellaneous 400
• Classic findings in narcolepsy:
– 1) Excessive daytime sleepiness
– 2) Cataplexy
– 3) Sleep paralysis
– 4) Hyponagogic or hypnopompic
hallucinations
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Miscellaneous 500
• Which main neurotransmitter is
supposedly involved in Alzheimer’s
disease?
• And where do these neurotransmitters
originate from?
Miscellaneous 500
• Cholinergic neurons in the basal forebrain
– Nucleus basalis of Meynert  cortex
– Medial septal nuclei + nucleus of diagonal band 
hippocampus
– Role in memory and learning
Miscellaneous 500
• Cholinergic neurons in
the pontomesencephalic
region
– 1) PTN + LTN  thalamus
 Cortex
– 2) PTN + LTN  BG,
tectum, cerebellum, pons,
medulla, sc
– Role in arousal and motor
systems
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Brainstem Vascular Supply 100
• Can you name 2 signs on exam which
highly suggest brainstem ischemia?
Brainstem Vascular Supply 100
• Crossed signs (sensory or motor)
• Wrong-way eyes (eyes looking away from
weakness)
• Eye movement abnormalities
• Pupillary abnormalities
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More Brainstem Vascular Supply
100
• Who lived here
from 1904 –
1914?
More Brainstem Vascular Supply
100
• Picasso lived at
Le Bateau Lavoir
from 1904
to1914.
• He painted Les
Demoiselles
d’Avignon during
this period.
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Brainstem Vascular Supply 200
• Can you name 3 lacunar syndromes
caused by ischemic lesions in the pons?
Brainstem Vascular Supply 200
•
•
•
Dysarthria hemiparesis, pure motor hemiparesis
Ataxic hemiparesis
Dysarthria-clumsy hand (paramedian basis pontis)
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More Brainstem Vascular Supply
200
• Can you list the symptoms and signs of
the lateral medullary syndrome?
• BONUS: Can you name the corresponding
brainstem region affected for each of the
above S/Sx?
More Brainstem Vascular Supply
200
Back to Jeopardy
Brainstem Vascular Supply 300
• Can you associate the appropriate brain
structure to each of the following S/Sx seen in
top-of-the-basilar syndrome?
– Visual disturbances
– Memory disturbances
– Eye mvt abnormalities
– Somnolence, delirium, vivid visual hallucinations
– Ataxia
Brainstem Vascular Supply 300
• Can you associate the appropriate brain
structure to each of the following S/Sx seen
in top-of-the-basilar syndrome?
– Visual disturbances  occipital lobe
– Memory disturbances  medial temporal lobes
– Eye mvt abnormalities  CNIII nuclei & fascicles
– Somnolence, delirium, vivid visual hallucinations
 midbrain reticular formation
– Ataxia  cerebellum
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More Brainstem Vascular Supply
300
• Occlusion of the paramedian branches of
the anterior spinal or vertebral arteries
would cause infarction in which area?
• BONUS: can you name 3 deficits caused
by this infarct?
More Brainstem Vascular Supply
300
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Brainstem Vascular Supply 400
• Which artist
painted this?
Brainstem Vascular Supply 400
• The Lacemaker,
by Vermeer
(1669-1671)
Brainstem Vascular Supply 400
• BONUS: Which painting by the same artist
hangs in our ex-chief’s living room?
Brainstem Vascular Supply 400
• The Milkmaid, by
Vermeer (16571658)
• …a reproduction,
not the original.
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More Brainstem Vascular Supply
400
• Can you differentiate between Weber,
Claude and Benedikt syndromes?
More Brainstem Vascular Supply
400
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Brainstem Vascular Supply 500
• What kind of infarct is caused by occlusion
of the artery of Percheron before it
bifurcates?
Brainstem Vascular Supply 500
• Bilateral medial midbrain or bilateral
thalamic infarcts
– Paramedian branches arise from top of the
basilar and enter the interpeduncular fossa to
supply the medial midbrain and thalamus
– Sometimes these arteries bifurcate AFTER
their origin  arteries of Percheron, thus
causing BILATERAL infarcts
Brainstem Vascular Supply 500
Back to Jeopardy
More Brainstem Vascular Supply
500
• How much does this
structure weigh?
• How much pressure
does it exert on its
foundations?
More Brainstem Vascular Supply
500
• La Tour Eiffel:
– Weight: 10 000 tons
– Pressure on
foundations: 4,5 kg /
cm2 (equivalent of a
man sitting on a
chair…)
Back to Jeopardy