Neuroanatomy Flashcards

1
Q

What are the 6 layers of the cortex (superficial to deep)?

A

Molecular (plexiform) layer
External granular layer
External pyramidal layer
Internal granular layer
Internal pyramidal layer
Multiform (fusiform) layer

(MP EG EP IG IP MF)

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2
Q

What are the 3 FUNCTIONAL layers of the cortex?

A
  1. Supragranular layers (I-III)
  2. Internal granular layer (IV)
  3. Infragranular layers (V & VI)
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3
Q

Where do intracortical connections primarily originate and terminate (layer)?

A

Functional: supragranular layers (I-III which are molecular/plexiform, external granular, and external pyramidal)

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4
Q

What are the 2 main types of intracortical connections?

A

Associational (intrahemispheric)
&
Commissural (to contralateral hemisphere, usu thru corpus callosum)

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5
Q

What does the internal granular layer do, i.e. where do its connections come from?

A

Receives thalamocortical connections, esp from thalamic nuclei
Most prominent in primary sensory cortices

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6
Q

What do the infragranular layers mostly do?

A

Connect cortex & subcortical regions

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7
Q

Where are the infragranular layers most developed?

A

Motor cortex

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8
Q

Which part of the brain has extremely small or non-existent granular layers and is aka the “agranular” cortex?

A

Motor cortex

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9
Q

What layer gives rise to all of the principal cortical efferent projections to basal ganglia, brainstem, and spinal cord?

A

Layer V (internal pyramidal)

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10
Q

Where does layer VI go?

A

Mostly to the thalamus
aka the multiform or fusiform layer

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11
Q

What’s Nelson’s syndrome?

A

In the setting of Cushing’s disease (ACTH) s/p bilateral adrenalectomy, but the adenoma keeps growing and secreting ACTH

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12
Q

Does Nelson’s syndrome have Crooke’s cells?

A

Crooke’s cells are found in pituitaries of Cushing’s disease, but not in the pituitary surrounding the adenomas of Nelson’s syndrome (so no)

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13
Q

What structures make up the diencephalon?

A
  • Thalamus
  • Hypothalamus including the Neurohypophysis
  • Subthalamus
  • Epithalamus
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14
Q

What structures make up the epithalamus?

A

Ant & post paraventricular nuclei
Medial & lat Habenular nuclei
Stria medullaris thalami
Posterior commissure
Pineal Body

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15
Q

What are 3 changes you see in mammillary bodies in Wernicke’s?

A
  1. Soft granular parenchyma (& atrophy?)
  2. Abnormal capillaries with microhemorrhage (slides & grossly)
  3. Reactive astrocytes
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16
Q

What are the 3 hereditary motor & sensory neuropathies?

A
  1. Charcot-Marie-Tooth
  2. HMSN II
  3. Dejerine-Sottas neuropathy
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17
Q

What’s the disease with onion bulbs on EM and what are they?

A

Charcot-Marie-Tooth

Schwann cell hyperplasia i.t.s.o repetitive de- & remyelinations

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18
Q

What’s the protein you should telegraph for Charcot-Marie-Tooth?

A

PMP22
peripheral myelin protein 22

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19
Q

What’s the first test you do to eval for Charcot-Marie-Tooth? and why

A

Single-gene testing for PMP22 duplication/deletion
PMP22 duplication (a 1.5-Mb duplication at 17p11.2 that includes PMP22) accounts for as much as 50% of all CMT

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20
Q

what is the most common neoplasm family that happens in the pineal region?

A

germ cell tumors!
(germinoma > teratoma > choriocarcinoma&raquo_space; yolk sac & embryonal)

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21
Q

describe the path of the gag reflex (lol WHAT)

A

Touch receptors in pharyngeal mucosa (CNIX)
Solitary nucleus
Nucleus ambiguus
CNX
Muscles of palate

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22
Q

Brown Sequard 3 main issues with ipsi or contralateral (NOT levels, NOT tracts)

A
  1. Ipsilateral flaccid paralysis/loss of cutaneous sensation
  2. Ipsilateral spastic paralysis & loss of vibration sense, proprioception, & fine touch
  3. Contralateral loss of pain & temp
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23
Q

Brown Sequard issue & why it happens bc of the tracts affected (NOT levels)

A
  1. Ipsilateral flaccid paralysis d/t LMN loss (anterior corticospinal tract)
  2. Ipsilateral spastic paralysis d/t loss of moderation by UMN of lateral corticospinal tract; loss of vibration sense, proprioception, & fine touch d/t posterior/dorsal columns (fasciculus Gracilis (leGs) &/or fasciculus cuneatus (arms))
  3. Contralateral loss of pain & temp d/t spinothalamic tract
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24
Q

Brown Sequard ipsi/contra consequences WITH LEVELS

A
  1. Ipsi flaccid + band of sensory loss AT level of lesion
  2. Ipsi spastic + contra loss of vibration/proprio/fine touch BELOW level of lesion
  3. Contra loss of pain & temp 1-2 levels below lesion
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25
What are the ELEVEN (ugh) structures served by the anterior choroidal artery?
1. Choroid plexus (LV & 3rd vent) 2. Optic chiasm & tract 3. Internal capsule 4. LGN 5. Globus pallidus 6. Tail of the caudate 7. Hippo 8. Amygdala 9. Substantia nigra 10. Red nucleus 11. Crus cerebri
26
Which structure served by the anterior choroidal artery also has partially redundant blood supply, and where does it come from?
Posterior limb of internal capsule Lenticulostriate arteries from MCA
27
What vessels can cause lateral medullary syndrome?
PICA (specifically lateral medullary segment) Vertebral artery
28
What's the eponym for lateral medullary syndrome?
Wallenberg
29
What are the 7 structures affected in lateral medullary syndrome?
1. Vestibular nuclei 2. Inferior cerebellar peduncle 3. Central tegmental tract 4. Lateral spinothalamic tract 5. Spinal trigeminal nucleus & tract 6. Nucleus ambiguus (incl vagus & glossopharyngeal nerves) 7. Descending sympathetic fibers
30
LMS: what happens when the vestibular nuclei are infarcted?
Vomiting Vertigo Nystagmus
31
LMS: what happens when the inferior cerebellar peduncle is infarcted?
Ipsilateral ataxia, dysmetria (past pointing), dysdiadochokinesia
32
LMS: what happens when the central tegmental tract is infarcted?
Palatal myoclonus
33
LMS: what happens when the lateral spinothalamic tract is infarcted?
Contralateral loss of pain & temp from BODY (limbs & torso)
34
LMS: what happens when the spinal trigeminal nucleus & tract are infarcted?
ipsilateral loss of pain & temp from FACE
35
LMS: what happens when the nucleus ambiguus is infarcted?
Ipsilateral laryngeal, pharyngeal, & palatal hemiparalysis (dysphagia, hoarseness, diminished gag d/t efferent limb of CNX)
36
LMS: what happens when the descending sympathetic fibers are infarcted?
Ipsilateral Horner's syndrome (ptosis, miosis, & anhidrosis)
37
What is Grinker's myelinopathy?
Anoxic leukoencephalopathy or delayed post-hypoxic leukoencephalopathy (white matter & BG)
38
Key finding in FCD Ia
Abnormal radial cortical lamination (a-b; r-t)
39
Key finding in FCD Ib
Abnormal tangential cortical lamination (a-b; r-t)
40
Key finding in FCD Ic
Abnormal radial AND tangential cortical lamination (i.e. Ia + Ib)
41
Key finding in FCD IIa
Dysmorphic neurons
42
Key finding in FCD IIb
Dysmorphic neurons AND balloon cells (b for balloon, IIb is for the 2 Ls in ballon)
43
Key finding in FCD IIIa
Temporal lobe, a/w hippo sclerosis
44
Key finding in FCD IIIb
Adjacent to glial or glioneuronal tumor
45
Key finding in FCD IIIc
Adjacent to vascular malformation
46
Key finding in FCD IIId
Adjacent to any other lesion acquired during early life (trauma, ischemic injury, encephalitis, etc)
47
What's the Guillain-Mollaret triangle?
CONTRALATERAL dentate Ipsilateral red Ipsilateral inf olivary
48
What's hypertrophic olivary degeneration (why do you get it and why is it weird)
Primary lesion in dentato-rubro-olivary pathway > Transneuronal degen of inf olivary nucleus > HYPERTROPHY of inf olivary nucleus (not atrophy!)
49
Where do parallel fibers come from?
Granule cells in cerebellar cortex
50
What do parallel fibers form?
Excitatory synapses onto dendrites of Purkinje cells & dendrites of inhib interneurons basket cells & stellate cells (molec layer)
51
Grumose degeneration
Degeneration of dentate nucleus of cerebellum: accumulation of granular eo material which is actually swollen/degen Purkinje axons (it looks like axonal spheroids on neurofilament or synapto IHC, just in the cerebellum
52
Name 3 things that can show grumose degeneration
1. PSP 2. Dentatorubropallidoluysian atrophy 3. Spinocerebellar ataxia type 3
53
What are the 2 main (broad) categories of "disorders of forebrain induction"?
Holoprosencephaly & agenesis of the corpus callosum
54
Define holoprosencephaly.
Developmental defect of forebrain (prosencephalon which includes telencephalon and diencephalon) where you have incomplete separation of the cerebral hemispheres into R & L
55
What are the 3 types of holoprosencephaly?
1. Alobar/complete (worst) (no separation, one ventricle) 2. Semilobar/incomplete (some separation, usu posterior) 3. Lobar (focal fusion along midline, either at OFC or cingulate)
56
What are the issues with noses/smell that you can get with holoprosencephaly?
1. No olfactory bulbs 2. Anosmia 3. Congenital nasal pyriform aperture stenosis
57
What are 3 infections that have been a/w holoprosencephaly?
Toxoplasmosis Syphilis Rubella
58
What are 3 teratogens that have been a/w holoprosencephaly?
Ethanol Retinoic acid Cholesterol synthesis inhibitors
59
What is the frequency of genetic etiology of holoprosencephaly?
50% of cases have cytogenetic abnormalities
60
What is the most common genetic etiology of holoproscencephaly?
Trisomy 13 (75% of trisomy 13 cases have holoprosencephaly)
61
Gene for Smith-Lemli-Opitz syndrome
DHCR7 on chromosome 11 (functions in cholesterol synthesis)
62
What structure is usually missing in partial agenesis of the CC?
Splenium (posterior)
63
Name 3 syndromes a/w agenesis of the CC
1. Aicardi 2. Andermann 3. Meckel
64
What are 3 broad categories of "malformations of cortical development"?
1. Lissencephaly 2. Heterotopias 3. Cortical dysplasias with cytomegaly
65
Name 3 cortical malformations that occur due to abnormal neurogenesis.
1. Microcephaly 2. Hemimegalencephaly 3. Focal cortical dysplasia
66
Name 3 cortical malformations that occur due to abnormal neuronal migration.
1. Periventricular heterotopia 2. Subcortical band heterotopia 3. Lissencephaly
67
Name 1 cortical malformation that occurs due to abnormal arrest in neuronal migration
Cobblestone (type 2) lissencephaly
68
What gene is associated with autosomal recessive lissencephaly?
RELN (7q22)
69
What gene is a/w Miller-Dieker syndrome?
LIS1 & 14-3-3' YWHAE continuous deletion (17p13.3) targeted LoFxn alleles of Pafah1b1 & 14-3-3'
70
What gene is associated with autosomal dominant lissencephaly?
LIS1 & 14-3-3' YWHAE continuous deletion (17p13.3) targeted LoFxn alleles of Pafah1b1 & 14-3-3'
71
What is the mode of inheritance of Miller-Dieker syndrome?
Autosomal dominant (haploinsufficiency)
72
What is the mode of inheritance of isolated lissencephaly sequence?
Autosomal dominant
73
What gene is a/w isolated lissencephaly sequence?
LIS1 deletion alone (17p13.3) targeted LoFxn alleles of Pafah1b1
74
What genes are a/w X-linked lissencephaly?
DCX (Xq22.3-q23) (DOMINANT) ARX (Xp22.13)
75
What is the main difference in cortical morphology btwn LIS1 mutation and DCX mutation?
Both are 4 layer cortex, but LIS1 is posterior DCX is anterior
76
What is the main difference in morphology between LIS1, DCX, and ARX mutations?
ARX = 3 layer LIS1 & DCX = 4 layer
77
Is ARX lissencephaly 3 layer or 4 layer?
Threeeeeeeeeeeeeeee
78
What does LIS1 encode?
non-catalytic subunit of plt activating factor acetyl hydrolase (dynein > neuronal migration)
79
What are the facial features a/w Miller-Dieker? and are they d/t LIS1 or 14-3-3 mut?
microcephaly (lissencephaly) bitemporal narrowing micrognathia vertical ridging in forehead D/t 14-3-3 (or just not LIS1) bc LIS1 causes the lissencephaly
80
Mode of inheritance of DCX lissencephaly
X-linked dominant (males)
81
Mode of inheritance of ARX lissencephaly & the name of the syndrome
X-linked recessive XLAG (X-linked lissencephaly with ambiguous genitalia)
82
mode of inheritance of cobblestone/type 2 lissencephaly
autosomal recessive
83
What does the cortex look like microscopically in cobblestone/type 2 lissencephaly?
Unlayered and totally disorganized
84
What are the 2 other organ systems that can be abnormal in cobblestone/type 2 lissencephaly?
Muscular Ocular
85
why is it called cobblestone lissencephaly
the neurons? go to the MENINGES??? and they pooch the brain out and make the meninges super thick, so it looks cobblestoned
86
gene for Fukuyama congenital muscular dystrophy
FCMD (9q31)
87
Gene for muscle-eye-brain disease types A, 5 B, 5 C, 5
FKRP (19q13.3)
88
Gene for Walker Warburg syndrome
POMT1 (9q31-33) POMT2 (14q24.3)
89
2 genes a/w muscle-eye-brain disease (not the A, B, C)
POMGnT1 (1p34-33) LARGE (22q12)
90
what is the underlying theme of all the types of cobblestone lissencephaly genes?
All result in hypoglycosylation (issues with glycosyl transferases) (alpha dystroglycans)
91
What does Walker Warburg have clinically?
HARD + E Hydrocephalus Agyria (lissencephaly (cobblestone)) Retinal Dysplasia Encephalocele (occipital) also muscular dystrophy and also vermal agenesis/cerebellar dysplasia
92
Define grey matter heterotopia
Neurons and glia that form a region of grey matter in an abnormal location
93
What are the 2 main classes of grey matter heterotopia?
Nodular Band/Laminar
94
Gene and inheritance pattern of familial subependymal heterotopia?
Gene: FLNA on Xq28 (Filamin 1) X-linked dominance (happens in females, lethal in males)
95
Gene in periventricular nodular heterotopia with microcephaly (and inheritance i guess)
ARFGEF2 Auto recessive
96
What gene is a/w band heterotopia?
DCX (double cortin) (also a/w lissencephaly)
97
Which layer of the cortex has the largest neurons?
Layer V
98
what genetic abnormalities are FCD IIb a/w?
somatic mutations in mTOR pathway
99
Genes a/w tuberous sclerosis
TSC1 chrom 9: hamartin TSC2 chrom 16: tuberin (tumor suppressors; when mutated, mTOR path is upregulated)
100
where does the recurrent artery of Heubner come from?
anterior cerebral artery
101
what does the recurrent artery of Heubner supply?
think Heubner’s HAMBUrgers H: head of caudate + ant hypothalamus A: anterior internal capsule + nucleus accumbens M: Meynert + medial GP B: diagonal band of Broca U: parts of uncinate fasciculus
102
where does the anterior choroidal artery come from?
internal carotid (not quite MCA)
103
what does the anterior choroidal artery supply?
the Choroid is DEEP in the EYE (deep structures, optic pathways) 1. optic radiations/posterior internal capsule 2. optic tract 3. LGN/lateral thalamus LGN leads to everything near it: hippo + amygdala + tail of caudate + GPi + cerebral peduncle (lat) + choroid plexus in LV
104
what is anterior choroidal artery syndrome?
Hemiplegia Hemianesthesia Contralateral hemianopia
105
primary (only) efferent pathway from hippocampus
fornix
106
what cell type does Wernicke's NOT affect?
Neurons
107
which is medial & which is lateral: fasciculus cuneatus and gracilis
medial: gracilis (when you say grace you put your hands together in the middle) lateral: cuneatus
108
Somatotopy of dorsal columns. Go! + aff or eff?
cuneate: cervical and thoracic (lat to med) (CuneaTe has C & T) gracilis: lumbar (lat) and sacral (med - bc it's sacrament, cause you're saying grace) both are Afferent (Ascending)
109
somatotopy of lateral corticospinal tract + aff or eff?
medial to lateral: C > T > L > S Efferent/dEscending
110
somatotopy of anterolateral system
medial to lateral: C > T > L > S Afferent (Ascending)
111
how can you orient spinal cord based on BVs?
Posterior spinal arteries are Paired Anterior is Alone
112
what other thing are Arnold Chiari type 2 malformations a/w?
lumbosacral myelomeningocele & hydrocephalus
113
what is a type 1 arnold-chiari
herniation of cerebellar tonsil thru foramen magnum
114
what is a type 2 arnold-chiari
herniation of cerebellar vermis & downward displacement of brainstem (+/- buckling)
115
what is a type 3 arnold-chiari
cerebello-encephalocele herniation thru occipitocervical or high cervical bony defect (like a big neck cyst with cerebellar herniation into it) (this feels like a spina bifida but it's like, maybe sometimes above the spine)
116
what is syringobulbia and what does it usually occur with?
a slit-like cavity in the brainstem usu a/w syringomyelia
117
what is diastematomyelia?
a split in the spinal cord at midline by a spur of tissue (bony, cartilaginous, or fibrous) (type of spina bifida)
118
what is the main function of the BG
tonically inhibit movement
119
what's the direct pathway?
cortex > striatum > GPi > thalamus (you inhibit the thalamus & brainstem, and when they are inhibited, THEIR inhibition decreases, which lets you move? i think? so double-inhibition) has one synapse = direct synapse is stratum > GPi
120
what's the indirect pathway
indirect = multisynaptic cortex > striatum > GPe > subthalamic nucleus > GPi + SN pars reticulata allows for fine-tuned BG output = more controlled movement (same result, movement, just has more synapses bc subthal is involved)
121
which cranial nerve nuclei are in the midbrain?
III (has 2: Edinger-Westphal + Oculomotor) IV (trochlear) V (1 part: mesencephalic trigeminal)
122
which cranial nerve nuclei are in the pons?
V (2 parts: trigeminal motor & principal sensory trigeminal) VI (abducens) VII (facial motor) VIII (1: vestibular)
123
what cranial nerves are in the salivatory nucleus (medulla)
superior: VII inferior: IX & X
124
what cranial nerves are in the nucleus ambiguus?
IX & X
125
what cranial nerves are in the solitary nucleus?
VII IX X
126
what are the NUCLEI (not cranial nerves necessarily) in the medulla?
Cochlear (VIII) Solitary (VII, IX, X) Salivatory (sup VII & inf IX & X) Nucleus ambiguus (IX & X) Hypoglossal (XII) Dorsal motor nucleus of vagus (X)
127
which cranial nerve nuclei are in the spinal cord?
accessory (XI) spinal trigeminal (V, VII, IX, X)
128
Dural innervation (ugh???)
Supratentorial: small meningeal branches of trigeminal (V1, V2, and V3) Infratentorial: upper cervical nerves
129