Exam 5: Axonal Pathfinding

Axonal growth cones from amphibian retinal ganglion cells are directed to their tectal targets by

If a section of the embryonic amphibian brainstem is removed and rotated early in development, what will happen to the axonal projections of the Mauthner cells, which normally project to the spinal cord?

What provides force to push the tip of a growth cone out and pull it back again?

Corpus callosum axons grow toward the midline because they are

Growing longitudinal neurons express _______ and do so _______.

If a Drosophila is found to have axons that cross back and forth over the body's midline several times, it is most likely

In later development, after axons have innervated their targets, neurons grow to accommodate the overall growth of the body by adding microtubules

How is it that agenesis of the corpus callosum at birth can go undetected, but if the corpus callosum is severed in adults, they experience "disconnection syndrome"?

Why do neurons that cross the midline not cross back over more than once? Describe how the changes in expression of membrane receptors in the crossing neuron influence the neuron's movement in response to the diffusible proteins secreted by the midline.

Which family of guidance proteins contains both diffusible and contact guidance molecules?

How did the results of Sperry's rotated frog eye experiment relate to the nature versus nurture debate?

Axons push growth cones forward when microtubules are added

Conditions resulting in the total or partial absence of a corpus callosum in childhood

Which of the following is a receptor for netrin?

Why do motor neuron axons only grow though the rostral half of a somite?

When a growth cone reaches a repulsive cue,

Neurons that send axons across the midline are known as _______ neurons.

In growth cone guidance, what is the difference between contact guidance and chemotropism?

What provides a structural core to an extending growth cone?

In the experiment that led to Sperry's chemoaffinity hypothesis optic nerve of a frog was severed and then put back in place after being rotated. When the nerve regenerated, the frog's vision was mirror-reversed (as demonstrated by the frog's behavioral responses to stimuli in the eye). What did these results suggest about where the retina reinnervated the tectum, and what directed this reinnervation? What is the chemoaffinity hypothesis that was derived from this result?