Prob Set 7 Q&A - Problem Set 7 Cellular...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Problem Set 7 Cellular Neurobiology Fall 2010 1. How does the presence of limbs affect the embryonic development of motor neuron populations? Describe an experiment that revealed this result. In developing nervous systems, the embryo produces around three times more neurons than necessary and eventually trims down the excess neurons based on the size of the target and the amount of neurotrophic factor it secretes. The neurotrophic hypothesis suggests that the target muscles only provide enough neurotrophic factor for a fraction of the total number of motor neurons. The survival of the motor neurons depends upon their synapsing with a muscle and receiving these growth factors so they can survive. In this way, the muscles can dictate the size of the neuronal population innervating them. The experiment discussed in class used chick embryos and showed that by adding or removing limbs during embryonic development, one could control the number of surviving motor neurons. More limb = more neurotrophin = more neurons and visa versa. 2. Describe the experiment Roger Sperry performed that allowed him to arrive at the Chemoaffinity Hypothesis. How did the results of this experiment support his theory? Frog retinal ganglion cell axons are able to regenerate when severed. Roger Sperry used this property to his advantage by cutting the optic nerves that connect the retina of a frog to the tectum, rotating the eye 180 degrees and observing how the axons regenerate. He
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern