Brain development

Question 1

What are the 3 basic processes?

Answer 1

Produce neurons, place neurons where they belong, connect neurons

Question 2

What is known as the shock absorber of the NS?

Answer 2

Cortico-spinal-fluid filled chambers of the brain

Question 3

Describe step 1 - cell proliferation (4)

Answer 3

Undifferentiated stem cells grow extension. Cell nucleus moves up to down & duplicated DNA. Nucleus moves down, cell retracts extension + divides in two. Cells behave differently depending on whether divided horizontally or vertically.

Question 4

What happens if cells split vertically compared to horizontally

Answer 4

Vertically - both daughter cells repeat process. Horizontal - one repeats, one moves away and won’t divide again

Question 5

Describe step 2 (cell migration)

Answer 5

Pyramidal cells/astrocytes originate from dorsal areas and migrate vertically. Inhibitory neurons and oligodendroglia migrate laterally

Question 6

What is the pathway that radial glia cells take?

Answer 6

Extend thin processes towards surface in ordered pattern.

Question 7

Step 3 - connecting cells - what are the 3 problems to be solved?

Answer 7

Find right direction and target structure. Find right target cells inside target structure.

Question 8

Describe the pathway of undifferentiated neurons

Answer 8

Cells to migrate take up residence in subplate layer. Cells migrate to cortical plate. First to layer VI, then V, then IV e.t.c. Interneurons move in sideways.

Question 9

What are the 3 problems?

Answer 9

Each hemisphere receives signals from and sends commands to contralateral. Signals are only attracted to specific target structure chemicals. How can chemical cues differentiate between cells?

Question 10

Define pruning

Answer 10

Only useful synapses are maintained, useless ones disappear

Question 11

What is the difference between useful and useless synapses

Answer 11

Useful = will link 2 neurons which are both active or silent at the same time. Useless = will link 2 neurons which are rarely active/silent at the same time

Question 12

Why are useful synapses useful? (3)

Answer 12

Because creates orders structure, otherwise, energy is wasted on something that contributes nothing. Prenatally, correlated activity is established through spontaneous waves of retinal activity