Author Question: Eyes and optic tectums grow at different rates. As they grow, the synaptic connections that were ... (Read 60 times)

anjilletteb · **on:** Jun 22, 2018

Eyes and optic tectums grow at different rates. As they grow, the synaptic connections that were originally formed on the tectum by axons of retinal ganglion cells shift so that the retina is always fully and faithfully mapped on the tectum.

This finding supports the
A) chemoaffinity hypothesis.
B) pioneer hypothesis.
C) topographic-gradient hypothesis.
D) all of the above
E) both A and C

Question 2

In support of the topographic-gradient hypothesis, it has been shown that

A) axons do not grow out from the retinas until the retinas are fully grown, which is why babies have disproportionately large eyes.
B) axons do not grow out from the retinas until their target structures (e.g., optic tectums) are fully grown.
C) retinas and optic tectums always grow in precise proportion to one another.
D) the synaptic connections originally formed by retinal ganglion cells on the optic tectums gradually shift as both the eyes and optic tectums grow at different rates during development.
E) both A and B