Neuro Development

Question 1

What does the ectodermal layer become?

Answer 1

Neural tube forms the adult spinal cord and brain

Neural crest forms PNS

Question 2

What is the formation of the neural tube called?

Answer 2

Neurulation

Question 3

What are the two conditions of dysfunctional neural tube fusion

Answer 3

Anencephaly: head fails to develop

Spina bifida: lump at base of spine

Folic acid reduces instances of this by 90%

Question 4

What are the 3 sequential processes of cells finding the right place in the brain

Answer 4

1. Proliferation
2. Migration
3. Differentiation

Question 5

Describe cell movement in proliferation

Answer 5

Cell travels from ventricular surface to Pial surface (DNA replication) then back again

Question 6

2 cell fates of a cell in proliferation

Answer 6

1. Proliferation again
2. ## MigrationDetermined by transcription factors

Question 7

Describe the transcription factors in a proliferating cell

Answer 7

1. Notch-1 and Numb travel to opposite poles
2. Vertical cleavage will produce identical daughter cells and so will continue to proliferate
3. Horizontal cleavage produces a cell without Numb which prevents further cell division and triggers migration

Question 8

What provides the scaffold for migration

Answer 8

Radial glia that project between ventricular and marginal zone

Question 9

How would you describe the layering of developing cortical cells

Answer 9

Inside-out cortical development

Question 10

How is cortical layering controlled?

Answer 10

1. Genetically: transcription factors

2. Gde2 inhibits notch, in mice without Gde2 cells fail to migrate and so development is lopsided

Question 11

What occurs in dysfunctional reeler

Answer 11

1. Reelin is a glycoprotein that helps neurones trans locate after they’ve detached from radial glia
2. Without Reelin development becomes outside-in due to neurone traffic jam

Question 12

Describe the theory for contrived expiation in primates

Answer 12

1. Symmetric neurogenic expansion (intermediate progenitor hypothesis)
2. Additional amplification processes allow for greater number of neural columns per glial cell

Question 13

What are the 4 mechanisms of axon targeting

Answer 13

1. Trial and error: many axons project, only useful ones survive
2. Chemoattraction/ repulsion
3. Pathway labelling: specific points in pathway to direct
4. Axons simply growing together in pairs

Question 14

Name the 3 decision points in axon targeting

Answer 14

1. Pathway selection: left or right?
2. Target secretion: area A or area B
3. Address selection: neurone A or neurone B