brain development

Question 1

How does the brain maintain contralateral control?

Answer 1

Each hemisphere receives input from and sends output to the opposite side of the body (e.g., right hand → left hemisphere).

Question 2

How do growing axons find the correct direction?

Answer 2

They are guided by chemical signals in the environment based on their location and chemical affinities.

Question 3

How do axons find the correct target structure?

Answer 3

They respond to specific chemical signals emitted by their intended target structures.

Question 4

How do axons find the correct target cell?

Answer 4

Through maps in the sensory and motor cortices and dynamic, coordinated electrical activity between cells.

Question 5

What are Brodmann areas?

Answer 5

Cortical regions distinguished by different cytoarchitecture (cell structure and organization).

Question 6

What is the brain’s general strategy for wiring neurons?

Answer 6

Initial overabundance of synapses, followed by pruning based on activity.

Question 7

What determines whether a synapse is kept or pruned?

Answer 7

Correlated activity (pre- and postsynaptic neurons active together) strengthens synapses; uncorrelated activity weakens them.

Question 8

What is prenatal correlated activity based on?

Answer 8

Spontaneous waves of activity, such as from the retina, before birth.

Question 9

Why do newborns need to learn to see?

Answer 9

Coordinating input from both eyes requires actual visual experience, not just spontaneous prenatal activity.