Wiring

Question 1

These function to “sniff” out the environment as a neuron grows.

Answer 1

Growth cones

Question 2

These 2 structures are specialized sensors on the ends of developing neurons.

Answer 2

Lamellipodia and filipodia at the tips of growth cones

Question 3

True or False. Growth cones tunnel their way through the terrain at a constant rate and speed.

Answer 3

False. As they reach certain landmarks, they change their shape and speed.

Question 4

What happens once a growth cone reaches their final destination?

Answer 4

Differentiates and develops a presynaptic terminal

Question 5

What molecule forms the meshwork of lamellapodia and filipodia in growth cones?

Answer 5

F-actin

Question 6

These cells serve as landmarks at critical decision points in pathways.

Answer 6

Guidepost cells

Question 7

What are the 2 ways in which guidepost cells direct growing axons?

Answer 7

Diffusible molecules

Cell surface molecules

Question 8

Which cells interact with growth cones on growing axons?

Answer 8

Guidepost cells

Question 9

These cells are crucial in the layout of the developing cortex and hippocampus. What type are they? What cells do they help?

Answer 9

Cajal-Retzius cells
Guidepost cell
Pyramidal neurons

Question 10

How to Cajal-Retzius cells help pyramidal neurons reach their targets in cortex?

Answer 10

Secrete reelin

Question 11

These cells in the developing nervous system are the FIRST to set up pathways.

Answer 11

Pioneer neurons

Question 12

These are cells which latch onto a previously laid out trail and form fascicles.

Answer 12

Follower neurons

Question 13

Which type of neuron has more filipodia- pioneer neurons or follower neurons?

Answer 13

Pioneer neurons

Question 14

These are pioneer neurons that also transmit sensory information from periphery to the CNS during development.

Answer 14

Rohon-Beard neurons

Question 15

Which cells act as primary sensory cells in developing nervous system? Mature nervous system?

Answer 15

Rohon-Beard neurons

Dorsal root ganglia cells

Question 16

Cajal-Retzius cells are an example of which 2 types of neurons?

Answer 16

Guidepost cells

Pioneer neurons

Question 17

How do pyramidal neurons get into each layer of the cortex?

Answer 17

Pioneer Cajal-Retzius neurons pave pathways and end up in Layer 1 (marginal zone). As pyramidal neurons develop, their growth cones extend along previously paved paths and move along radial glia toward the CR guidepost cells in Layer 1.

Question 18

What is the fate of Cajal-Retzius cells?

Answer 18

Eventually they die

Question 19

Chemical molecules can guide developing axons. In what 2 ways?

Answer 19

Secreted molecules as local or long distance cues

Tethered or membrane-associated molecules as short-distance cues

Question 20

These 3 molecules are part of the ECM and interact with what receptor on developing axons?

Answer 20

Laminin
Collagen
Fibronectin
Integrins

Question 21

How do developing axons recognize “other” and retract, or “self/same” and grow?

Answer 21

CAMs and cadherins

Question 22

How do our brains replicate the maps we sense in the environment and maintain their integrity in the brain?

Answer 22

Series of overlaying gradients

Question 23

What cells see the environment and relay that information to the brain?

Answer 23

Retinal ganglion cells

Question 24

How to retinal ganglion cell axons identify the correct regional post-synaptic cells while retaining the visual map?

Answer 24

Multiple gradients of ephrin/Eph signaling

Question 25

What is the benefit to using gradients of soluble factors and their receptors to make maps within the brain?

Answer 25

Can use a limited number of gene products and still get vast uniqueness

Question 26

What 2 molecule/receptor pairs are crucial in mediating decussation pathways?

Answer 26

Robo/Slit

Netrin/DCC

Question 27

In mature neurons, axons end in what? In developing neurons, axons end in what?

Answer 27

Mature- presynaptic terminals

Developing- growth cone