L11, L12 Cell Survival and Death, Specificity and Synaptic Connections

Question 1

NGF is required for the survival of what?

Answer 1

sympathetic and DRG neurons in developing during the critical period - may be removed afterwards

Question 2

what are neurotrophins ?

Answer 2

they help the neurons make their connections in the CNS

NGD is a member of this family

Question 3

what are neurotrophins required for?

Answer 3

-Required for proliferation, differentiation and survival of neural crest cells.

Question 4

what are neurotrophins provided by?

Answer 4

• Provided by the neurons and the mesenchymal tissues initially.
  
  • Provided by their targets after maturation.

Question 5

what is the neurotrophins low affinity receptor?

Answer 5

p75

Question 6

what is the neurotrophins high affinity receptor?

Answer 6

Trk oncogene

Question 7

what does activation of neurotrophins receptors lead to?

Answer 7

activation of Phospholipase C, PIP3, and MPA kinase cascade

Question 8

neurotrophins may play a role in..?

Answer 8

curing Alzheimer’s

Question 9

define apoptosis?

Answer 9

programmed cell death

Question 10

what is the importance of apoptosis in neural development?

Answer 10

allows for sole innervations of motor units

Question 11

growing neurons are competing for vital substance released by what?

Answer 11

the target - only one neuron can win!

Question 12

how do axons sort themselves?

Answer 12

anterior-posterior manner - specificity based on repulsion

Question 13

what is responsible for repulsion of axons?

Answer 13

ephrin family of tyrosine kinases

Question 14

what is the role of ephrin?

Answer 14

ephrin ligands repel each ether
- if ephrin is expressed in posterior tectum, the termporal ganglion cells (retinal) which also produce ephrin will repel eachother and make their connection with the anterior tectum instead

Question 15

what does differential ephrin A2 and A5 expression allow?

Answer 15

for the gradients to provide proper pathways for retinal neuron growth.

Question 16

skeletal motor end plates may have many neurons attached during when?

Answer 16

later embryonic development

Question 17

synapses of skeletal motor neurons____ due to competition to leave the motoneuron with singular innervations

Answer 17

retract

Question 18

The visual projections from the Lateral Geniculate Nucleus to the Visual Cortex are formed ______upon the visual experience in early life.

Answer 18

dependent

Question 19

after development, the fibers of the visual projections bcome ____

Answer 19

myelinated - this is a period of plasticity in development

Question 20

In a normally-developed visual system, the area of dominance columns for both eyes is the _____,

Answer 20

same

Question 21

and each cortical cell responds to visual input according to its _____

Answer 21

column

Question 22

____ ______ during early life prevents this balance from developing, and the non-deprived eye assumes control of nearly all cortical cells.

Answer 22

Monocular deprivation

Question 23

what does it indicate if columns are even on left and right?

Answer 23

normal

Question 24

what does it indicate if larger column on one side ?

Answer 24

ocular dominance

Question 25

When born, all cells of the cortex layer 4 are driven by ______

Answer 25

both eyes.

Question 26

After 6 weeks, all cells of the cortex layer 4 are driven by ____

Answer 26

one eye

Question 27

The ______are alternations of cells driven by the left and right eye respectively.

Answer 27

“columns”

Question 28

how long is the critical period?

Answer 28

3 mo.

Question 29

During this critical period, if one eye is close or has cataracts the ocular columns of that eye will ___.

Answer 29

shrink

Question 30

Even if the cataract or closure is repaired after 3 months that eye will always fail to drive ____

Answer 30

cortical cells. (Cause depolarization)