L3 - neurodevelopment

Question 1

instructions for brain on assembling cells

Answer 1

genomic control

Question 2

how are the different component of the brain organised and differentiated

Answer 2

transcription factors and morphogenes

Question 3

how are components of the brain connected

Answer 3

neural circuitry

Question 4

is the genome a conserved structure

Answer 4

yes

Question 5

give an example of genetic divergence between species

Answer 5

dolphin and camel have very wrinkly cerebral cortex

squirrel and frog do not

Question 6

gyrification

Answer 6

how wrinkly the cerebral cortex is

Question 7

which organims is used to study neural development

and why is it useful

Answer 7

C. Elegans (worm)
small and simple - 302 neurons
allows complete tracking of cell developent

Question 8

what technique is used to model neural tube formation

Answer 8

SEM

Scanning electron microscopy

Question 9

process of neural tube formation

Answer 9

neural plate forma furrow at medial hinge point
neural groove forms as two sides converge
epidermis forms top layer
neural crest forms middle layer (peripheral NS)
neural tube bottom layer

Question 10

what direction does neural tube formation occur in

Answer 10

from top to bottom

like a zip

Question 11

what do dorso and ventral refer to in dorsoventral axis

Answer 11

dorso - sensory neurons

ventral - motor neurons

Question 12

brainstem is divided into…

Answer 12

rhomberes

Question 13

rhombere organisation

Answer 13

determined by Homeobox (Hox) gene expression

Question 14

what is a rhombere

Answer 14

segment of developing neural tube

Question 15

Timing and localization to the neural tube closure can lead to?

Answer 15

neural tube defects

e.g. anencephaly, spina bifida

Question 16

where are cranial nerves restricted to?

Answer 16

specific rhomberes

Question 17

Shh gradient

Answer 17

high Shh in ventral

low Shh in dorsal

Question 18

increase in Shh concentration means….

Answer 18

increase in motor neurons

Question 19

Shh is important for determining…

Answer 19

neural identity

Question 20

what is produced by low Shh concentration

Answer 20

dorsal interneurons

Question 21

ventral motorneurons require high Shh conc for

Answer 21

induction

Question 22

progenitor domains

Answer 22

cell populations defined by combinations of transcription factors

Question 23

transcription factors specify neuronal subtypes

Answer 23

within progenitor subtypes

Question 24

what is a growth cone

Answer 24

specialist structure that guides neurones

Question 25

axons grow towards

Answer 25

positive, attractive signals

Question 26

axons grow by

Answer 26

polymerisation of cytoskeleton

Question 27

what signals growth cones to targets

Answer 27

chemotactic or haptotactic stimulus

Question 28

haptotactic stimulus

Answer 28

e.g. more adhesion sites

Question 29

-ve cues

Answer 29

repel, cause downstream collapse of cytoskeleton

Question 30

why is midline crossing important

Answer 30

relied upon by locomotion and sensory coordination | allows both sides of the NS to communicate

Question 31

diagram for midline crossing

Answer 31

ladder diagram longitudinal or crossed directions neuromeres are the sections

Question 32

Robo

Answer 32

transmembrane receptor mutants cause growth in circles continuous crossing of midline

Question 33

Slit

Answer 33

chemorepellant ligand mutants cause collapse of axon tracts down the midline growth only down middle

Question 34

neurophilin receptor and semaphorin ligand

Answer 34

essential for patterning peripheral nerves

Question 35

factors that regulate complex development of cns

Answer 35

nerve growth factors | neurotrophic factors

Question 36

how is neural plate formed

Answer 36

interaction of neural ectoderm with notochord

Question 37

where does neural plate form furrow

Answer 37

medial hinge point

Question 38

importance of HOX transcription factors

Answer 38

determine organisation between rostral and caudal axis | determine rhombomere organisation

Question 39

what determines dorsoventral axis

Answer 39

shh

Question 40

arguement against Shh dorsoventral hypothesis

Answer 40

studies on mice mutants for Shh lack ventral spinal cord characteristics

Question 41

what relies of communication of both sides of the CNS

Answer 41

locomotion sensory coordination higher cognitive functioning

Question 42

what is required for proper midline crossing

Answer 42

proper interaction between robo receptor and slit ligand

Question 43

what is netrin

Answer 43

chemotropic signal secreted by floor plate

Question 44

netrin deficient mice

Answer 44

do not form hippocampal commissure or corpus callosum

Question 45

netrin-3

Answer 45

PNS | limited in CNS