Fate Mapping Studies of Neural Crest Cell Migration Have Been

question 29

Multiple Choice

Fate mapping studies of neural crest cell migration have been carried out in chicks,quails,and mice.These studies have shown that the neural crest cells that populate the second pharyngeal arch arise from which level(s) of the brain?

• A) Midbrain only
• B) Midbrain and rhombomere 1
• C) Rhombomeres 1 and 2
• D) Rhombomere 4
• E) Rhombomeres 5 and 6

---

Definitions:

Conditioned Stimulus

A previously neutral stimulus that, after being paired with an unconditioned stimulus, elicits a conditioned response.

Operant Conditioning

A process of behavioral adjustment where the level of an action is modified through the application of rewards or punishments.

Extinction

In psychology, the gradual weakening and disappearance of a conditioned response tendency.

Reinforcement

A concept in behavioral psychology where a behavior is strengthened or increased by following it with a positive or rewarding stimulus.