Zaidi: Neural Development

Question 1

Phase 1 neural development

Answer 1

Different cell types develop independently at separate locations

Question 2

Phase 2 neural development

Answer 2

Axons and dendrites grow out along specific routes setting up provisional but orderly network of connections

Question 3

Phase 3 neural development

Answer 3

Continues into adult life, connections are adjusted and refined through continued interactions

Question 4

Neurons are produced in association with

Answer 4

Glial cells

Question 5

CNS derived from

Answer 5

Neural tube

Question 6

PNS derived from

Answer 6

Neural crest

Question 7

What controls differentiation into neurons

Answer 7

Delta notch signaling (lateral inhibition and positive feedback)

Question 8

Signals released from ventral and dorsal side of neural tube act as

Answer 8

Morphogens, causing neurons at different dorso-ventral positions to express different gene regulatory proteins

Question 9

Neural crest cells originate at the _____ end of neural tube

Answer 9

Dorsal end

Question 10

Fate of neural crest cells depends on

Answer 10

Where they migrate to and settle

Question 11

What controls the movement of the growth cone on axons

Answer 11

Cytoskeletal machinery

GTPases Rho and Rac control the assembly/disassembly of actin filaments, which controls movement of growth cone

Question 12

Projections from growth cone

Answer 12

Filopodia and lamelopodia

Question 13

Major cues to help growth cones find their way

Answer 13

Extracellular matrix environment

Chemotactic factors- released by neighboring cells, can be attractive or repulsive

Question 14

Contact guidance refers to

Answer 14

The tendency for growth cones to follow a path taken by other cells

Question 15

Matrix molecules such as laminin favor

Answer 15

Axonal outgrowth

Question 16

Matrix molecules such as chondroitin sulfate proteoglycans favor

Answer 16

Axon growth inhibition

Question 17

Contact guidance is mediated by

Answer 17

Homophilic cell adhesion molecules:

• Immunoglobulin superfamily
• Cadherin family

Question 18

Dorsal neurons of spinal cord

Answer 18

Receive and relay sensory information from sensory neurons

Question 19

Ventral neurons of spinal cord

Answer 19

Develop as motor neurons and send out long axons to connect with muscles

Question 20

First stage in guidance of commissural neurons

Answer 20

Secretion of netrin by cells of floor plate

Question 21

Binding of netrin to its receptor causes

Answer 21

Opening of TRPC – allows entry of extracellular calcium

Question 22

Entry of extracellular calcium leads to

Answer 22

Activation of machinery for extension of filopodia and movement of growth cone
(Non commissural neurons do not have netrin receptors, so they do not migrate towards floor plate)

Question 23

Midline cells secrete _____ which does what, and what is the other similar molecule that is secreted

Answer 23

Slit
Commissural neurons have slit receptor (Roundabout)
Slit repels growth cones and blocks entry into midline
Semaphorin is another repulsive signa, but on the outside, which causes the growth cone to travel in a narrow track

Question 24

What regulates which growth cones synapse and where they synapse

Answer 24

Signals from target tissues

Question 25

Neurotrophic factors

Answer 25

Target cell produces limited amount of specific neurotrophic factors needed for survival, axons that do not get enough undergo apoptosis

Question 26

Nerve growth factor- receptor name and function

Answer 26

Tyrosine kinase

Promotes survival of specific sensory neurons and sympathetic neurons

Question 27

Short term effect of NGF

Answer 27

Effect on growth cone and neurite extension. Effect is local, direct, rapid and independent of communication with cell body

Question 28

Long term effect of NGF

Answer 28

Effect on cell survival. Mediated by its receptor, uptake into cells via endocytosis and stimulation of downstream signaling pathways

Question 29

Synaptic remodeling dependent upon which 2 rules that create spacial order

Answer 29

Axons from cells in different regions of retina compete for tectal neurons
Axons from neighboring sites which are excited at the same time cooperate/collaborate to retain and strengthen synapses with tectal neurons

Question 30

Posterior retinal neurons prefer _______

Anterior retinal neurons prefer____

Answer 30

Posterior retinal neurons prefer anterior tectal neurons

Anterior retinal neurons have no preference

Question 31

Entry of calcium through glutamate receptor triggers

Answer 31

Lasting change in synaptic strength

Question 32

Synapses are strengthened by external events that cause

Answer 32

2 or more neurons to be activated at the same time

“Neurons that fire together, wire together”