Neurology and Special Senses

Question 1

Neural development Day 18

Answer 1

Notochord - induces overlying ectoderm to differentiate into neuroectoderm and form neural plate

Question 2

What does neural plate give rise to?

Answer 2

Neural tube and neural crest cells

Question 3

What does notochord become?

Answer 3

Nucleus pulpous of intervertebral disc in adults

Question 4

Dorsal vs Ventral plate in neural development

Answer 4

Dorsal: alar plate, sensory, regulated by TGF-B (including bone morphogenetic protein BMP)
Ventral: basal, motor, regulated by sonic hedgehog gene (SHH)

Question 5

Forebrain AKA

Answer 5

Prosencephalon

Question 6

Midbrain AKA

Answer 6

Mesencephalon

Question 7

Hindbrain AKA

Answer 7

Rhombencephalon

Question 8

Prosencephalon becomes

Answer 8

Telencephalon

Diencephalon

Question 9

Rhombencephalon becomes

Answer 9

Metencephalon

Myelencephalon

Question 10

What does telencephalon become?

Answer 10

Cerebral hemisphere, basal ganglia, lateral ventricles

Question 11

What does diencephalon become?

Answer 11

Thalamus, hypothalamus, retina, third ventricle

Question 12

What does mesencephalon become?

Answer 12

Mid brain and cerebral aqueduct

Question 13

What does metencephalon become?

Answer 13

Pons (and upper part of fourth ventricle)

Cerebellum

Question 14

What does myelencephalon become?

Answer 14

Medulla and lower part of fourth ventricle

Question 15

What does microglia originate from?

Answer 15

Mesoderm

Question 16

What does neural crest form?

Answer 16

PNS neurons, Schwann cells, glia, melanocytes, adrenal medulla

Question 17

What does the neuroepithelial of neural tube produce?

Answer 17

CNS neurons, ependymal cells, oligodendrocytes, astrocytes

Question 18

What is a neural tube defect?

Answer 18

Neuropores fail to fuse (4th week)= persistent connection between amniotic cavity and spinal canal

Question 19

What is neural tube defects associated with?

Answer 19

Diabetes and folate deficiency

Question 20

Neural tube defect confirmatory tests

Answer 20

Increased AFP in amniotic fluid and increased AChE

Question 21

What neural tube defect doesn’t have an increased AFP?

Answer 21

Spinal bifida occult

Question 22

What is spina bifida occult?

Answer 22

Failure of caudal neuropore to close but no herniation
Seen in lower vertebral levels
Dura is intact
Tuft of hair or skin dimple at level of bony defect

Question 23

What is a meningocele?

Answer 23

Meninges (but no neural tissue) herniate through bony defect

Question 24

What is myelomeningocecle?

Answer 24

Meninges and neural tissue herniate through bony defect

Question 25

What is myeloschisis?

Answer 25

AKA rachischisis | Exposed unfused neural tissue without skin/meningeal covering

Question 26

What is anencephaly?

Answer 26

Failure of rostral neuropore to close = no forebrain, open calvarium Polyhydramnois

Question 27

What is holoprosencephaly?

Answer 27

Failure of embryonic forebrain to separate into 2 cerebral hemispheres usually during weeks 5-6

Question 28

What causes holoprosencephaly?

Answer 28

Possible mutation in SHH

Question 29

What is holoprosencephaly additionally associated with?

Answer 29

Midline defects = cleft palate, and cyclopean, increased risk for pituitary dysfunction (diabetes insipidus)

Question 30

What syndrome can present with holoprosencephaly?

Answer 30

Patau | Trisomy 13

Question 31

MRI of holoprosencephaly

Answer 31

Monoventricle and fusion of basal ganglia

Question 32

What is lishencephaly

Answer 32

Failure of neuronal migration resulting in "smooth" brain that lacks sulci and gyri

Question 33

What is a chairi I malformation ?

Answer 33

Ectopia of cerebellar tonsils inferior to foramen magnum | Congenital, asymptomatic in childhood, headaches and cerebellar syndromes in adulthood

Question 34

What causes chiari I malformation?

Answer 34

Syringomyelia

Question 35

What is a Chiari II malformation?

Answer 35

Herniation of cerebellar vermin and tonsils through foramen magnum with aqueduct stenosis

Question 36

Aqueductal stenosis causes what kind of hydrocephalus?

Answer 36

Noncommunicating

Question 37

What is Chiari II malformations associated with?

Answer 37

Meylomeningocele (may present with paralysis/sensory loss at and below the level of the lesion)

Question 38

What Chiari malformation appears in childhood?

Answer 38

II

Question 39

What is Dandy-Walker malformation?

Answer 39

Agenesis of cerebellar vermis -> cystic enlargement of 4th ventricle that fills the enlarged posterior fossa

Question 40

What is DW malformation associated with?

Answer 40

Noncommunicating hydrocephalus, spina bifida

Question 41

What is a syringomyelia?

Answer 41

Cystic cavity within central canal of spinal cord

Question 42

What is damaged first in syringomyelia?

Answer 42

Anterior white commissure (spinothalamic tract) | = Cape like bilateral loss of pain and temperature sensation in upper extremities

Question 43

Most common for syringomyelia? C?T?L?

Answer 43

C>T>L