Neurogenesis Flashcards

1
Q

How does the neural tube form?

A
  • Neural plate folds
  • neural folds fuse into a hollow neural tube
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2
Q

What does the anterior section of the neural tube form?

A

Major brain regions

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3
Q

What does the posterior section of the neural tube form?

A

Spinal cord

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4
Q

What is the ventricular zone?

A

The area of neural tube that is initially only 1 cell thick

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5
Q

Why does the ventricular zone contain rapidly dividing precursors?

A

TO INCREASE THICKNESS OF THE ZONE

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6
Q

What do the daughter cells of the VZ differentiate into?

A

Neurons & glia

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7
Q

What occurs during pre-neurogenesis in the VZ?

A
  • early cell division of NEUROEPITHELIAL cells is SYMMETRIC
  • produces 2 eqivalent daughter NECs
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8
Q

What occurs during early neurogenesis in the VZ?

A

-ASYMMETRIC cell divison gives rise to different daughters:

*neural progenitor RGCs (radial glial cells)

*neurons

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9
Q

What is asymmetrical division in neurogenesis?

A

(two daughter cells with different cellular fates)

A tilted mitotic spindle correlates with unequal division of centrosomes.

  • older stays with the RGC stem cell
  • newer goes with the neuron
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10
Q

What cell type creates a scaffold for migration?

A

Radial glial cells (RGCs)

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11
Q

How do RGCs create a scaffold for migration?

A

Span from the VZ to outer Pia layer of developing brain

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12
Q

What happens to EARLY neurons in the VZ?

A

leave the VZ & migrate to form the deepest layers FIRST

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13
Q

What happens to LATER neurons in the VZ?

A

travel progressively further to build outer layers (i.e. closer to pia)

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14
Q

Name a factor that controls the final position of neurons migrating from the VZ

A

Environmental cues

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15
Q

What is reelin?

What is its function?

A

A glycoprotien secreted from the pia layer in early cerebellum development.

Enables neuronal migration thru already existing layers!

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16
Q

What are mouse ‘reeler’ mutants?

A

Mice that have cerebellar dysfiunction.

BECAUSE neuron layers are INVERTED (inside-out)

17
Q

What are Homeobox transcription factors?

A

One of the regulators of RGC proliferation vs expression of pro-neural genes

(a.k.a CONTROLS WHICH TYPE OF CELL THE NEUROEPITH. CELLS WILL DIFFERN. INTO!)

18
Q

Explain how neurogenesis is possible in ADULT mammals

A

New CNS neurons can be generated

-ventricular (neuronal) stem cells have been found!-

19
Q

Explain neurogenesis in songbirds

A

Young birds learn call from adult tutor

Once call is CRYSTALLISED, control & memory remain intact

In subsequent years, their performance requires annual regeneration of the PREMOTOR & MOTOR regions of CNS [because they forgot the song]
(i.e. annual increase in neurogenesis) –> triggered by increased testosterone

20
Q

What are the main benefits of neuronal stem cells in adults?

A

release of TROPHIC (GROWTH) FACTORS!

  • support remaining neurons
  • DO NOT create new synaptically-connected neuron replacements.
21
Q

What are neuronal stem cells attracted to?

A

NSCs are highly migatory

Attracted by processes involved in brian pathologies

  • inflam
  • astrocyte activation
  • new blood vessel formation